Merge with 08d121184a38a7bee1dd9de3cb171c6758d59310
authorrougeronj
Wed, 09 Sep 2015 15:18:53 +0200
changeset 513 d55176dc72cc
parent 512 480c1d2d6915 (current diff)
parent 498 08d121184a38 (diff)
child 514 d45e95229c47
Merge with 08d121184a38a7bee1dd9de3cb171c6758d59310
--- a/client/bower.json	Wed Sep 09 15:05:30 2015 +0200
+++ b/client/bower.json	Wed Sep 09 15:18:53 2015 +0200
@@ -24,22 +24,17 @@
     "tests"
   ],
   "dependencies": {
-    "backbone": "~1.1.2",
-    "jquery": "~2.1.3",
-    "jquery-mousewheel": "~3.1.12",
-    "paper": "~0.9.22",
+    "backbone": "~1.2.3",
+    "jquery": "~2.1.4",
+    "jquery-mousewheel": "~3.1.13",
+    "paper": "~0.9.24",
     "FileSaver": "*",
-    "backbone-relational": "~0.9.0",
+    "backbone-relational": "a7634e7d9deac64e3da455a3fde13b96ae253612",
     "requirejs": null,
-    "lodash": "~2.4.1",
+    "lodash": "~3.10.1",
     "ckeditor": "~4.4.7"
   },
   "devDependencies": {
     "jquery-ui": "~1.11.4"
-  },
-  "exportsOverride": {
-    "lodash": {
-      "": "dist/*.js"
-    }
   }
 }
--- a/server/php/basic/public_html/static/lib/backbone-relational/backbone-relational.js	Wed Sep 09 15:05:30 2015 +0200
+++ b/server/php/basic/public_html/static/lib/backbone-relational/backbone-relational.js	Wed Sep 09 15:18:53 2015 +0200
@@ -1,6 +1,6 @@
 /* vim: set tabstop=4 softtabstop=4 shiftwidth=4 noexpandtab: */
 /**
- * Backbone-relational.js 0.9.0
+ * Backbone-relational.js 0.10.0
  * (c) 2011-2014 Paul Uithol and contributors (https://github.com/PaulUithol/Backbone-relational/graphs/contributors)
  *
  * Backbone-relational may be freely distributed under the MIT license; see the accompanying LICENSE.txt.
@@ -1022,9 +1022,8 @@
 					}
 					else {
 						// If `merge` is true, update models here, instead of during update.
-						model = this.relatedModel.findOrCreate( attributes,
-							_.extend( { merge: true }, options, { create: this.options.createModels } )
-						);
+						model = ( _.isObject( attributes ) && options.parse && this.relatedModel.prototype.parse ) ?
+							this.relatedModel.prototype.parse( _.clone( attributes ), options ) : attributes;
 					}
 
 					model && toAdd.push( model );
@@ -1037,9 +1036,9 @@
 					related = this._prepareCollection();
 				}
 
-				// By now, both `merge` and `parse` will already have been executed for models if they were specified.
-				// Disable them to prevent additional calls.
-				related.set( toAdd, _.defaults( { merge: false, parse: false }, options ) );
+				// By now, `parse` will already have been executed just above for models if specified.
+				// Disable to prevent additional calls.
+				related.set( toAdd, _.defaults( { parse: false }, options ) );
 			}
 
 			// Remove entries from `keyIds` that were already part of the relation (and are thus 'unchanged')
@@ -1238,7 +1237,7 @@
 				var dit = this,
 					args = arguments;
 
-				if ( !Backbone.Relational.eventQueue.isLocked() ) {
+				if ( !Backbone.Relational.eventQueue.isBlocked() ) {
 					// If we're not in a more complicated nested scenario, fire the change event right away
 					Backbone.Model.prototype.trigger.apply( dit, args );
 				}
@@ -1494,12 +1493,16 @@
 				}
 			}
 
-			return $.when.apply( null, requests ).then(
+			return this.deferArray(requests).then(
 				function() {
 					return Backbone.Model.prototype.get.call( dit, attr );
 				}
 			);
 		},
+		
+		deferArray: function(deferArray) {
+			return Backbone.$.when.apply(null, deferArray);
+		},
 
 		set: function( key, value, options ) {
 			Backbone.Relational.eventQueue.block();
@@ -1827,7 +1830,7 @@
 		findOrCreate: function( attributes, options ) {
 			options || ( options = {} );
 			var parsedAttributes = ( _.isObject( attributes ) && options.parse && this.prototype.parse ) ?
-				this.prototype.parse( _.clone( attributes ) ) : attributes;
+				this.prototype.parse( _.clone( attributes ), options ) : attributes;
 
 			// If specified, use a custom `find` function to match up existing models to the given attributes.
 			// Otherwise, try to find an instance of 'this' model type in the store
@@ -1974,20 +1977,16 @@
 	};
 
 	/**
-	 * Override 'Backbone.Collection.remove' to trigger 'relational:remove'.
+	 * Override 'Backbone.Collection._removeModels' to trigger 'relational:remove'.
 	 */
-	var remove = Backbone.Collection.prototype.__remove = Backbone.Collection.prototype.remove;
-	Backbone.Collection.prototype.remove = function( models, options ) {
+	var _removeModels = Backbone.Collection.prototype.___removeModels = Backbone.Collection.prototype._removeModels;
+	Backbone.Collection.prototype._removeModels = function( models, options ) {
 		// Short-circuit if this Collection doesn't hold RelationalModels
 		if ( !( this.model.prototype instanceof Backbone.RelationalModel ) ) {
-			return remove.call( this, models, options );
+			return _removeModels.call( this, models, options );
 		}
 
-		var singular = !_.isArray( models ),
-			toRemove = [];
-
-		models = singular ? ( models ? [ models ] : [] ) : _.clone( models );
-		options || ( options = {} );
+		var toRemove = [];
 
 		//console.debug('calling remove on coll=%o; models=%o, options=%o', this, models, options );
 		_.each( models, function( model ) {
@@ -1995,7 +1994,7 @@
 			model && toRemove.push( model );
 		}, this );
 
-		var result = remove.call( this, singular ? ( toRemove.length ? toRemove[ 0 ] : null ) : toRemove, options );
+		var result = _removeModels.call( this, toRemove, options );
 
 		_.each( toRemove, function( model ) {
 			this.trigger( 'relational:remove', model, this, options );
--- a/server/php/basic/public_html/static/lib/backbone/backbone.js	Wed Sep 09 15:05:30 2015 +0200
+++ b/server/php/basic/public_html/static/lib/backbone/backbone.js	Wed Sep 09 15:18:53 2015 +0200
@@ -1,11 +1,16 @@
-//     Backbone.js 1.1.2
+//     Backbone.js 1.2.3
 
-//     (c) 2010-2014 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
+//     (c) 2010-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 //     Backbone may be freely distributed under the MIT license.
 //     For all details and documentation:
 //     http://backbonejs.org
 
-(function(root, factory) {
+(function(factory) {
+
+  // Establish the root object, `window` (`self`) in the browser, or `global` on the server.
+  // We use `self` instead of `window` for `WebWorker` support.
+  var root = (typeof self == 'object' && self.self == self && self) ||
+            (typeof global == 'object' && global.global == global && global);
 
   // Set up Backbone appropriately for the environment. Start with AMD.
   if (typeof define === 'function' && define.amd) {
@@ -17,15 +22,16 @@
 
   // Next for Node.js or CommonJS. jQuery may not be needed as a module.
   } else if (typeof exports !== 'undefined') {
-    var _ = require('underscore');
-    factory(root, exports, _);
+    var _ = require('underscore'), $;
+    try { $ = require('jquery'); } catch(e) {}
+    factory(root, exports, _, $);
 
   // Finally, as a browser global.
   } else {
     root.Backbone = factory(root, {}, root._, (root.jQuery || root.Zepto || root.ender || root.$));
   }
 
-}(this, function(root, Backbone, _, $) {
+}(function(root, Backbone, _, $) {
 
   // Initial Setup
   // -------------
@@ -34,14 +40,11 @@
   // restored later on, if `noConflict` is used.
   var previousBackbone = root.Backbone;
 
-  // Create local references to array methods we'll want to use later.
-  var array = [];
-  var push = array.push;
-  var slice = array.slice;
-  var splice = array.splice;
+  // Create a local reference to a common array method we'll want to use later.
+  var slice = Array.prototype.slice;
 
   // Current version of the library. Keep in sync with `package.json`.
-  Backbone.VERSION = '1.1.2';
+  Backbone.VERSION = '1.2.3';
 
   // For Backbone's purposes, jQuery, Zepto, Ender, or My Library (kidding) owns
   // the `$` variable.
@@ -60,17 +63,65 @@
   Backbone.emulateHTTP = false;
 
   // Turn on `emulateJSON` to support legacy servers that can't deal with direct
-  // `application/json` requests ... will encode the body as
+  // `application/json` requests ... this will encode the body as
   // `application/x-www-form-urlencoded` instead and will send the model in a
   // form param named `model`.
   Backbone.emulateJSON = false;
 
+  // Proxy Backbone class methods to Underscore functions, wrapping the model's
+  // `attributes` object or collection's `models` array behind the scenes.
+  //
+  // collection.filter(function(model) { return model.get('age') > 10 });
+  // collection.each(this.addView);
+  //
+  // `Function#apply` can be slow so we use the method's arg count, if we know it.
+  var addMethod = function(length, method, attribute) {
+    switch (length) {
+      case 1: return function() {
+        return _[method](this[attribute]);
+      };
+      case 2: return function(value) {
+        return _[method](this[attribute], value);
+      };
+      case 3: return function(iteratee, context) {
+        return _[method](this[attribute], cb(iteratee, this), context);
+      };
+      case 4: return function(iteratee, defaultVal, context) {
+        return _[method](this[attribute], cb(iteratee, this), defaultVal, context);
+      };
+      default: return function() {
+        var args = slice.call(arguments);
+        args.unshift(this[attribute]);
+        return _[method].apply(_, args);
+      };
+    }
+  };
+  var addUnderscoreMethods = function(Class, methods, attribute) {
+    _.each(methods, function(length, method) {
+      if (_[method]) Class.prototype[method] = addMethod(length, method, attribute);
+    });
+  };
+
+  // Support `collection.sortBy('attr')` and `collection.findWhere({id: 1})`.
+  var cb = function(iteratee, instance) {
+    if (_.isFunction(iteratee)) return iteratee;
+    if (_.isObject(iteratee) && !instance._isModel(iteratee)) return modelMatcher(iteratee);
+    if (_.isString(iteratee)) return function(model) { return model.get(iteratee); };
+    return iteratee;
+  };
+  var modelMatcher = function(attrs) {
+    var matcher = _.matches(attrs);
+    return function(model) {
+      return matcher(model.attributes);
+    };
+  };
+
   // Backbone.Events
   // ---------------
 
   // A module that can be mixed in to *any object* in order to provide it with
-  // custom events. You may bind with `on` or remove with `off` callback
-  // functions to an event; `trigger`-ing an event fires all callbacks in
+  // a custom event channel. You may bind a callback to an event with `on` or
+  // remove with `off`; `trigger`-ing an event fires all callbacks in
   // succession.
   //
   //     var object = {};
@@ -78,123 +129,234 @@
   //     object.on('expand', function(){ alert('expanded'); });
   //     object.trigger('expand');
   //
-  var Events = Backbone.Events = {
-
-    // Bind an event to a `callback` function. Passing `"all"` will bind
-    // the callback to all events fired.
-    on: function(name, callback, context) {
-      if (!eventsApi(this, 'on', name, [callback, context]) || !callback) return this;
-      this._events || (this._events = {});
-      var events = this._events[name] || (this._events[name] = []);
-      events.push({callback: callback, context: context, ctx: context || this});
-      return this;
-    },
-
-    // Bind an event to only be triggered a single time. After the first time
-    // the callback is invoked, it will be removed.
-    once: function(name, callback, context) {
-      if (!eventsApi(this, 'once', name, [callback, context]) || !callback) return this;
-      var self = this;
-      var once = _.once(function() {
-        self.off(name, once);
-        callback.apply(this, arguments);
-      });
-      once._callback = callback;
-      return this.on(name, once, context);
-    },
-
-    // Remove one or many callbacks. If `context` is null, removes all
-    // callbacks with that function. If `callback` is null, removes all
-    // callbacks for the event. If `name` is null, removes all bound
-    // callbacks for all events.
-    off: function(name, callback, context) {
-      var retain, ev, events, names, i, l, j, k;
-      if (!this._events || !eventsApi(this, 'off', name, [callback, context])) return this;
-      if (!name && !callback && !context) {
-        this._events = void 0;
-        return this;
-      }
-      names = name ? [name] : _.keys(this._events);
-      for (i = 0, l = names.length; i < l; i++) {
-        name = names[i];
-        if (events = this._events[name]) {
-          this._events[name] = retain = [];
-          if (callback || context) {
-            for (j = 0, k = events.length; j < k; j++) {
-              ev = events[j];
-              if ((callback && callback !== ev.callback && callback !== ev.callback._callback) ||
-                  (context && context !== ev.context)) {
-                retain.push(ev);
-              }
-            }
-          }
-          if (!retain.length) delete this._events[name];
-        }
-      }
-
-      return this;
-    },
-
-    // Trigger one or many events, firing all bound callbacks. Callbacks are
-    // passed the same arguments as `trigger` is, apart from the event name
-    // (unless you're listening on `"all"`, which will cause your callback to
-    // receive the true name of the event as the first argument).
-    trigger: function(name) {
-      if (!this._events) return this;
-      var args = slice.call(arguments, 1);
-      if (!eventsApi(this, 'trigger', name, args)) return this;
-      var events = this._events[name];
-      var allEvents = this._events.all;
-      if (events) triggerEvents(events, args);
-      if (allEvents) triggerEvents(allEvents, arguments);
-      return this;
-    },
-
-    // Tell this object to stop listening to either specific events ... or
-    // to every object it's currently listening to.
-    stopListening: function(obj, name, callback) {
-      var listeningTo = this._listeningTo;
-      if (!listeningTo) return this;
-      var remove = !name && !callback;
-      if (!callback && typeof name === 'object') callback = this;
-      if (obj) (listeningTo = {})[obj._listenId] = obj;
-      for (var id in listeningTo) {
-        obj = listeningTo[id];
-        obj.off(name, callback, this);
-        if (remove || _.isEmpty(obj._events)) delete this._listeningTo[id];
-      }
-      return this;
-    }
-
-  };
+  var Events = Backbone.Events = {};
 
   // Regular expression used to split event strings.
   var eventSplitter = /\s+/;
 
-  // Implement fancy features of the Events API such as multiple event
-  // names `"change blur"` and jQuery-style event maps `{change: action}`
-  // in terms of the existing API.
-  var eventsApi = function(obj, action, name, rest) {
-    if (!name) return true;
+  // Iterates over the standard `event, callback` (as well as the fancy multiple
+  // space-separated events `"change blur", callback` and jQuery-style event
+  // maps `{event: callback}`).
+  var eventsApi = function(iteratee, events, name, callback, opts) {
+    var i = 0, names;
+    if (name && typeof name === 'object') {
+      // Handle event maps.
+      if (callback !== void 0 && 'context' in opts && opts.context === void 0) opts.context = callback;
+      for (names = _.keys(name); i < names.length ; i++) {
+        events = eventsApi(iteratee, events, names[i], name[names[i]], opts);
+      }
+    } else if (name && eventSplitter.test(name)) {
+      // Handle space separated event names by delegating them individually.
+      for (names = name.split(eventSplitter); i < names.length; i++) {
+        events = iteratee(events, names[i], callback, opts);
+      }
+    } else {
+      // Finally, standard events.
+      events = iteratee(events, name, callback, opts);
+    }
+    return events;
+  };
+
+  // Bind an event to a `callback` function. Passing `"all"` will bind
+  // the callback to all events fired.
+  Events.on = function(name, callback, context) {
+    return internalOn(this, name, callback, context);
+  };
 
-    // Handle event maps.
-    if (typeof name === 'object') {
-      for (var key in name) {
-        obj[action].apply(obj, [key, name[key]].concat(rest));
-      }
-      return false;
+  // Guard the `listening` argument from the public API.
+  var internalOn = function(obj, name, callback, context, listening) {
+    obj._events = eventsApi(onApi, obj._events || {}, name, callback, {
+        context: context,
+        ctx: obj,
+        listening: listening
+    });
+
+    if (listening) {
+      var listeners = obj._listeners || (obj._listeners = {});
+      listeners[listening.id] = listening;
+    }
+
+    return obj;
+  };
+
+  // Inversion-of-control versions of `on`. Tell *this* object to listen to
+  // an event in another object... keeping track of what it's listening to
+  // for easier unbinding later.
+  Events.listenTo =  function(obj, name, callback) {
+    if (!obj) return this;
+    var id = obj._listenId || (obj._listenId = _.uniqueId('l'));
+    var listeningTo = this._listeningTo || (this._listeningTo = {});
+    var listening = listeningTo[id];
+
+    // This object is not listening to any other events on `obj` yet.
+    // Setup the necessary references to track the listening callbacks.
+    if (!listening) {
+      var thisId = this._listenId || (this._listenId = _.uniqueId('l'));
+      listening = listeningTo[id] = {obj: obj, objId: id, id: thisId, listeningTo: listeningTo, count: 0};
     }
 
-    // Handle space separated event names.
-    if (eventSplitter.test(name)) {
-      var names = name.split(eventSplitter);
-      for (var i = 0, l = names.length; i < l; i++) {
-        obj[action].apply(obj, [names[i]].concat(rest));
+    // Bind callbacks on obj, and keep track of them on listening.
+    internalOn(obj, name, callback, this, listening);
+    return this;
+  };
+
+  // The reducing API that adds a callback to the `events` object.
+  var onApi = function(events, name, callback, options) {
+    if (callback) {
+      var handlers = events[name] || (events[name] = []);
+      var context = options.context, ctx = options.ctx, listening = options.listening;
+      if (listening) listening.count++;
+
+      handlers.push({ callback: callback, context: context, ctx: context || ctx, listening: listening });
+    }
+    return events;
+  };
+
+  // Remove one or many callbacks. If `context` is null, removes all
+  // callbacks with that function. If `callback` is null, removes all
+  // callbacks for the event. If `name` is null, removes all bound
+  // callbacks for all events.
+  Events.off =  function(name, callback, context) {
+    if (!this._events) return this;
+    this._events = eventsApi(offApi, this._events, name, callback, {
+        context: context,
+        listeners: this._listeners
+    });
+    return this;
+  };
+
+  // Tell this object to stop listening to either specific events ... or
+  // to every object it's currently listening to.
+  Events.stopListening =  function(obj, name, callback) {
+    var listeningTo = this._listeningTo;
+    if (!listeningTo) return this;
+
+    var ids = obj ? [obj._listenId] : _.keys(listeningTo);
+
+    for (var i = 0; i < ids.length; i++) {
+      var listening = listeningTo[ids[i]];
+
+      // If listening doesn't exist, this object is not currently
+      // listening to obj. Break out early.
+      if (!listening) break;
+
+      listening.obj.off(name, callback, this);
+    }
+    if (_.isEmpty(listeningTo)) this._listeningTo = void 0;
+
+    return this;
+  };
+
+  // The reducing API that removes a callback from the `events` object.
+  var offApi = function(events, name, callback, options) {
+    if (!events) return;
+
+    var i = 0, listening;
+    var context = options.context, listeners = options.listeners;
+
+    // Delete all events listeners and "drop" events.
+    if (!name && !callback && !context) {
+      var ids = _.keys(listeners);
+      for (; i < ids.length; i++) {
+        listening = listeners[ids[i]];
+        delete listeners[listening.id];
+        delete listening.listeningTo[listening.objId];
       }
-      return false;
+      return;
     }
 
-    return true;
+    var names = name ? [name] : _.keys(events);
+    for (; i < names.length; i++) {
+      name = names[i];
+      var handlers = events[name];
+
+      // Bail out if there are no events stored.
+      if (!handlers) break;
+
+      // Replace events if there are any remaining.  Otherwise, clean up.
+      var remaining = [];
+      for (var j = 0; j < handlers.length; j++) {
+        var handler = handlers[j];
+        if (
+          callback && callback !== handler.callback &&
+            callback !== handler.callback._callback ||
+              context && context !== handler.context
+        ) {
+          remaining.push(handler);
+        } else {
+          listening = handler.listening;
+          if (listening && --listening.count === 0) {
+            delete listeners[listening.id];
+            delete listening.listeningTo[listening.objId];
+          }
+        }
+      }
+
+      // Update tail event if the list has any events.  Otherwise, clean up.
+      if (remaining.length) {
+        events[name] = remaining;
+      } else {
+        delete events[name];
+      }
+    }
+    if (_.size(events)) return events;
+  };
+
+  // Bind an event to only be triggered a single time. After the first time
+  // the callback is invoked, its listener will be removed. If multiple events
+  // are passed in using the space-separated syntax, the handler will fire
+  // once for each event, not once for a combination of all events.
+  Events.once =  function(name, callback, context) {
+    // Map the event into a `{event: once}` object.
+    var events = eventsApi(onceMap, {}, name, callback, _.bind(this.off, this));
+    return this.on(events, void 0, context);
+  };
+
+  // Inversion-of-control versions of `once`.
+  Events.listenToOnce =  function(obj, name, callback) {
+    // Map the event into a `{event: once}` object.
+    var events = eventsApi(onceMap, {}, name, callback, _.bind(this.stopListening, this, obj));
+    return this.listenTo(obj, events);
+  };
+
+  // Reduces the event callbacks into a map of `{event: onceWrapper}`.
+  // `offer` unbinds the `onceWrapper` after it has been called.
+  var onceMap = function(map, name, callback, offer) {
+    if (callback) {
+      var once = map[name] = _.once(function() {
+        offer(name, once);
+        callback.apply(this, arguments);
+      });
+      once._callback = callback;
+    }
+    return map;
+  };
+
+  // Trigger one or many events, firing all bound callbacks. Callbacks are
+  // passed the same arguments as `trigger` is, apart from the event name
+  // (unless you're listening on `"all"`, which will cause your callback to
+  // receive the true name of the event as the first argument).
+  Events.trigger =  function(name) {
+    if (!this._events) return this;
+
+    var length = Math.max(0, arguments.length - 1);
+    var args = Array(length);
+    for (var i = 0; i < length; i++) args[i] = arguments[i + 1];
+
+    eventsApi(triggerApi, this._events, name, void 0, args);
+    return this;
+  };
+
+  // Handles triggering the appropriate event callbacks.
+  var triggerApi = function(objEvents, name, cb, args) {
+    if (objEvents) {
+      var events = objEvents[name];
+      var allEvents = objEvents.all;
+      if (events && allEvents) allEvents = allEvents.slice();
+      if (events) triggerEvents(events, args);
+      if (allEvents) triggerEvents(allEvents, [name].concat(args));
+    }
+    return objEvents;
   };
 
   // A difficult-to-believe, but optimized internal dispatch function for
@@ -211,22 +373,6 @@
     }
   };
 
-  var listenMethods = {listenTo: 'on', listenToOnce: 'once'};
-
-  // Inversion-of-control versions of `on` and `once`. Tell *this* object to
-  // listen to an event in another object ... keeping track of what it's
-  // listening to.
-  _.each(listenMethods, function(implementation, method) {
-    Events[method] = function(obj, name, callback) {
-      var listeningTo = this._listeningTo || (this._listeningTo = {});
-      var id = obj._listenId || (obj._listenId = _.uniqueId('l'));
-      listeningTo[id] = obj;
-      if (!callback && typeof name === 'object') callback = this;
-      obj[implementation](name, callback, this);
-      return this;
-    };
-  });
-
   // Aliases for backwards compatibility.
   Events.bind   = Events.on;
   Events.unbind = Events.off;
@@ -248,7 +394,7 @@
   var Model = Backbone.Model = function(attributes, options) {
     var attrs = attributes || {};
     options || (options = {});
-    this.cid = _.uniqueId('c');
+    this.cid = _.uniqueId(this.cidPrefix);
     this.attributes = {};
     if (options.collection) this.collection = options.collection;
     if (options.parse) attrs = this.parse(attrs, options) || {};
@@ -271,6 +417,10 @@
     // CouchDB users may want to set this to `"_id"`.
     idAttribute: 'id',
 
+    // The prefix is used to create the client id which is used to identify models locally.
+    // You may want to override this if you're experiencing name clashes with model ids.
+    cidPrefix: 'c',
+
     // Initialize is an empty function by default. Override it with your own
     // initialization logic.
     initialize: function(){},
@@ -302,14 +452,19 @@
       return this.get(attr) != null;
     },
 
+    // Special-cased proxy to underscore's `_.matches` method.
+    matches: function(attrs) {
+      return !!_.iteratee(attrs, this)(this.attributes);
+    },
+
     // Set a hash of model attributes on the object, firing `"change"`. This is
     // the core primitive operation of a model, updating the data and notifying
     // anyone who needs to know about the change in state. The heart of the beast.
     set: function(key, val, options) {
-      var attr, attrs, unset, changes, silent, changing, prev, current;
       if (key == null) return this;
 
       // Handle both `"key", value` and `{key: value}` -style arguments.
+      var attrs;
       if (typeof key === 'object') {
         attrs = key;
         options = val;
@@ -323,37 +478,40 @@
       if (!this._validate(attrs, options)) return false;
 
       // Extract attributes and options.
-      unset           = options.unset;
-      silent          = options.silent;
-      changes         = [];
-      changing        = this._changing;
-      this._changing  = true;
+      var unset      = options.unset;
+      var silent     = options.silent;
+      var changes    = [];
+      var changing   = this._changing;
+      this._changing = true;
 
       if (!changing) {
         this._previousAttributes = _.clone(this.attributes);
         this.changed = {};
       }
-      current = this.attributes, prev = this._previousAttributes;
 
-      // Check for changes of `id`.
-      if (this.idAttribute in attrs) this.id = attrs[this.idAttribute];
+      var current = this.attributes;
+      var changed = this.changed;
+      var prev    = this._previousAttributes;
 
       // For each `set` attribute, update or delete the current value.
-      for (attr in attrs) {
+      for (var attr in attrs) {
         val = attrs[attr];
         if (!_.isEqual(current[attr], val)) changes.push(attr);
         if (!_.isEqual(prev[attr], val)) {
-          this.changed[attr] = val;
+          changed[attr] = val;
         } else {
-          delete this.changed[attr];
+          delete changed[attr];
         }
         unset ? delete current[attr] : current[attr] = val;
       }
 
+      // Update the `id`.
+      this.id = this.get(this.idAttribute);
+
       // Trigger all relevant attribute changes.
       if (!silent) {
         if (changes.length) this._pending = options;
-        for (var i = 0, l = changes.length; i < l; i++) {
+        for (var i = 0; i < changes.length; i++) {
           this.trigger('change:' + changes[i], this, current[changes[i]], options);
         }
       }
@@ -401,13 +559,14 @@
     // determining if there *would be* a change.
     changedAttributes: function(diff) {
       if (!diff) return this.hasChanged() ? _.clone(this.changed) : false;
-      var val, changed = false;
       var old = this._changing ? this._previousAttributes : this.attributes;
+      var changed = {};
       for (var attr in diff) {
-        if (_.isEqual(old[attr], (val = diff[attr]))) continue;
-        (changed || (changed = {}))[attr] = val;
+        var val = diff[attr];
+        if (_.isEqual(old[attr], val)) continue;
+        changed[attr] = val;
       }
-      return changed;
+      return _.size(changed) ? changed : false;
     },
 
     // Get the previous value of an attribute, recorded at the time the last
@@ -423,17 +582,16 @@
       return _.clone(this._previousAttributes);
     },
 
-    // Fetch the model from the server. If the server's representation of the
-    // model differs from its current attributes, they will be overridden,
-    // triggering a `"change"` event.
+    // Fetch the model from the server, merging the response with the model's
+    // local attributes. Any changed attributes will trigger a "change" event.
     fetch: function(options) {
-      options = options ? _.clone(options) : {};
-      if (options.parse === void 0) options.parse = true;
+      options = _.extend({parse: true}, options);
       var model = this;
       var success = options.success;
       options.success = function(resp) {
-        if (!model.set(model.parse(resp, options), options)) return false;
-        if (success) success(model, resp, options);
+        var serverAttrs = options.parse ? model.parse(resp, options) : resp;
+        if (!model.set(serverAttrs, options)) return false;
+        if (success) success.call(options.context, model, resp, options);
         model.trigger('sync', model, resp, options);
       };
       wrapError(this, options);
@@ -444,9 +602,8 @@
     // If the server returns an attributes hash that differs, the model's
     // state will be `set` again.
     save: function(key, val, options) {
-      var attrs, method, xhr, attributes = this.attributes;
-
       // Handle both `"key", value` and `{key: value}` -style arguments.
+      var attrs;
       if (key == null || typeof key === 'object') {
         attrs = key;
         options = val;
@@ -454,46 +611,43 @@
         (attrs = {})[key] = val;
       }
 
-      options = _.extend({validate: true}, options);
+      options = _.extend({validate: true, parse: true}, options);
+      var wait = options.wait;
 
       // If we're not waiting and attributes exist, save acts as
       // `set(attr).save(null, opts)` with validation. Otherwise, check if
       // the model will be valid when the attributes, if any, are set.
-      if (attrs && !options.wait) {
+      if (attrs && !wait) {
         if (!this.set(attrs, options)) return false;
       } else {
         if (!this._validate(attrs, options)) return false;
       }
 
-      // Set temporary attributes if `{wait: true}`.
-      if (attrs && options.wait) {
-        this.attributes = _.extend({}, attributes, attrs);
-      }
-
       // After a successful server-side save, the client is (optionally)
       // updated with the server-side state.
-      if (options.parse === void 0) options.parse = true;
       var model = this;
       var success = options.success;
+      var attributes = this.attributes;
       options.success = function(resp) {
         // Ensure attributes are restored during synchronous saves.
         model.attributes = attributes;
-        var serverAttrs = model.parse(resp, options);
-        if (options.wait) serverAttrs = _.extend(attrs || {}, serverAttrs);
-        if (_.isObject(serverAttrs) && !model.set(serverAttrs, options)) {
-          return false;
-        }
-        if (success) success(model, resp, options);
+        var serverAttrs = options.parse ? model.parse(resp, options) : resp;
+        if (wait) serverAttrs = _.extend({}, attrs, serverAttrs);
+        if (serverAttrs && !model.set(serverAttrs, options)) return false;
+        if (success) success.call(options.context, model, resp, options);
         model.trigger('sync', model, resp, options);
       };
       wrapError(this, options);
 
-      method = this.isNew() ? 'create' : (options.patch ? 'patch' : 'update');
-      if (method === 'patch') options.attrs = attrs;
-      xhr = this.sync(method, this, options);
+      // Set temporary attributes if `{wait: true}` to properly find new ids.
+      if (attrs && wait) this.attributes = _.extend({}, attributes, attrs);
+
+      var method = this.isNew() ? 'create' : (options.patch ? 'patch' : 'update');
+      if (method === 'patch' && !options.attrs) options.attrs = attrs;
+      var xhr = this.sync(method, this, options);
 
       // Restore attributes.
-      if (attrs && options.wait) this.attributes = attributes;
+      this.attributes = attributes;
 
       return xhr;
     },
@@ -505,25 +659,27 @@
       options = options ? _.clone(options) : {};
       var model = this;
       var success = options.success;
+      var wait = options.wait;
 
       var destroy = function() {
+        model.stopListening();
         model.trigger('destroy', model, model.collection, options);
       };
 
       options.success = function(resp) {
-        if (options.wait || model.isNew()) destroy();
-        if (success) success(model, resp, options);
+        if (wait) destroy();
+        if (success) success.call(options.context, model, resp, options);
         if (!model.isNew()) model.trigger('sync', model, resp, options);
       };
 
+      var xhr = false;
       if (this.isNew()) {
-        options.success();
-        return false;
+        _.defer(options.success);
+      } else {
+        wrapError(this, options);
+        xhr = this.sync('delete', this, options);
       }
-      wrapError(this, options);
-
-      var xhr = this.sync('delete', this, options);
-      if (!options.wait) destroy();
+      if (!wait) destroy();
       return xhr;
     },
 
@@ -536,7 +692,8 @@
         _.result(this.collection, 'url') ||
         urlError();
       if (this.isNew()) return base;
-      return base.replace(/([^\/])$/, '$1/') + encodeURIComponent(this.id);
+      var id = this.get(this.idAttribute);
+      return base.replace(/[^\/]$/, '$&/') + encodeURIComponent(id);
     },
 
     // **parse** converts a response into the hash of attributes to be `set` on
@@ -557,7 +714,7 @@
 
     // Check if the model is currently in a valid state.
     isValid: function(options) {
-      return this._validate({}, _.extend(options || {}, { validate: true }));
+      return this._validate({}, _.defaults({validate: true}, options));
     },
 
     // Run validation against the next complete set of model attributes,
@@ -573,23 +730,19 @@
 
   });
 
-  // Underscore methods that we want to implement on the Model.
-  var modelMethods = ['keys', 'values', 'pairs', 'invert', 'pick', 'omit'];
+  // Underscore methods that we want to implement on the Model, mapped to the
+  // number of arguments they take.
+  var modelMethods = { keys: 1, values: 1, pairs: 1, invert: 1, pick: 0,
+      omit: 0, chain: 1, isEmpty: 1 };
 
   // Mix in each Underscore method as a proxy to `Model#attributes`.
-  _.each(modelMethods, function(method) {
-    Model.prototype[method] = function() {
-      var args = slice.call(arguments);
-      args.unshift(this.attributes);
-      return _[method].apply(_, args);
-    };
-  });
+  addUnderscoreMethods(Model, modelMethods, 'attributes');
 
   // Backbone.Collection
   // -------------------
 
   // If models tend to represent a single row of data, a Backbone Collection is
-  // more analagous to a table full of data ... or a small slice or page of that
+  // more analogous to a table full of data ... or a small slice or page of that
   // table, or a collection of rows that belong together for a particular reason
   // -- all of the messages in this particular folder, all of the documents
   // belonging to this particular author, and so on. Collections maintain
@@ -611,6 +764,16 @@
   var setOptions = {add: true, remove: true, merge: true};
   var addOptions = {add: true, remove: false};
 
+  // Splices `insert` into `array` at index `at`.
+  var splice = function(array, insert, at) {
+    at = Math.min(Math.max(at, 0), array.length);
+    var tail = Array(array.length - at);
+    var length = insert.length;
+    for (var i = 0; i < tail.length; i++) tail[i] = array[i + at];
+    for (i = 0; i < length; i++) array[i + at] = insert[i];
+    for (i = 0; i < tail.length; i++) array[i + length + at] = tail[i];
+  };
+
   // Define the Collection's inheritable methods.
   _.extend(Collection.prototype, Events, {
 
@@ -625,7 +788,7 @@
     // The JSON representation of a Collection is an array of the
     // models' attributes.
     toJSON: function(options) {
-      return this.map(function(model){ return model.toJSON(options); });
+      return this.map(function(model) { return model.toJSON(options); });
     },
 
     // Proxy `Backbone.sync` by default.
@@ -633,32 +796,21 @@
       return Backbone.sync.apply(this, arguments);
     },
 
-    // Add a model, or list of models to the set.
+    // Add a model, or list of models to the set. `models` may be Backbone
+    // Models or raw JavaScript objects to be converted to Models, or any
+    // combination of the two.
     add: function(models, options) {
       return this.set(models, _.extend({merge: false}, options, addOptions));
     },
 
     // Remove a model, or a list of models from the set.
     remove: function(models, options) {
+      options = _.extend({}, options);
       var singular = !_.isArray(models);
       models = singular ? [models] : _.clone(models);
-      options || (options = {});
-      var i, l, index, model;
-      for (i = 0, l = models.length; i < l; i++) {
-        model = models[i] = this.get(models[i]);
-        if (!model) continue;
-        delete this._byId[model.id];
-        delete this._byId[model.cid];
-        index = this.indexOf(model);
-        this.models.splice(index, 1);
-        this.length--;
-        if (!options.silent) {
-          options.index = index;
-          model.trigger('remove', model, this, options);
-        }
-        this._removeReference(model, options);
-      }
-      return singular ? models[0] : models;
+      var removed = this._removeModels(models, options);
+      if (!options.silent && removed) this.trigger('update', this, options);
+      return singular ? removed[0] : removed;
     },
 
     // Update a collection by `set`-ing a new list of models, adding new ones,
@@ -666,78 +818,88 @@
     // already exist in the collection, as necessary. Similar to **Model#set**,
     // the core operation for updating the data contained by the collection.
     set: function(models, options) {
+      if (models == null) return;
+
       options = _.defaults({}, options, setOptions);
-      if (options.parse) models = this.parse(models, options);
+      if (options.parse && !this._isModel(models)) models = this.parse(models, options);
+
       var singular = !_.isArray(models);
-      models = singular ? (models ? [models] : []) : _.clone(models);
-      var i, l, id, model, attrs, existing, sort;
+      models = singular ? [models] : models.slice();
+
       var at = options.at;
-      var targetModel = this.model;
+      if (at != null) at = +at;
+      if (at < 0) at += this.length + 1;
+
+      var set = [];
+      var toAdd = [];
+      var toRemove = [];
+      var modelMap = {};
+
+      var add = options.add;
+      var merge = options.merge;
+      var remove = options.remove;
+
+      var sort = false;
       var sortable = this.comparator && (at == null) && options.sort !== false;
       var sortAttr = _.isString(this.comparator) ? this.comparator : null;
-      var toAdd = [], toRemove = [], modelMap = {};
-      var add = options.add, merge = options.merge, remove = options.remove;
-      var order = !sortable && add && remove ? [] : false;
 
       // Turn bare objects into model references, and prevent invalid models
       // from being added.
-      for (i = 0, l = models.length; i < l; i++) {
-        attrs = models[i] || {};
-        if (attrs instanceof Model) {
-          id = model = attrs;
-        } else {
-          id = attrs[targetModel.prototype.idAttribute || 'id'];
-        }
+      var model;
+      for (var i = 0; i < models.length; i++) {
+        model = models[i];
 
         // If a duplicate is found, prevent it from being added and
         // optionally merge it into the existing model.
-        if (existing = this.get(id)) {
-          if (remove) modelMap[existing.cid] = true;
-          if (merge) {
-            attrs = attrs === model ? model.attributes : attrs;
+        var existing = this.get(model);
+        if (existing) {
+          if (merge && model !== existing) {
+            var attrs = this._isModel(model) ? model.attributes : model;
             if (options.parse) attrs = existing.parse(attrs, options);
             existing.set(attrs, options);
-            if (sortable && !sort && existing.hasChanged(sortAttr)) sort = true;
+            if (sortable && !sort) sort = existing.hasChanged(sortAttr);
+          }
+          if (!modelMap[existing.cid]) {
+            modelMap[existing.cid] = true;
+            set.push(existing);
           }
           models[i] = existing;
 
         // If this is a new, valid model, push it to the `toAdd` list.
         } else if (add) {
-          model = models[i] = this._prepareModel(attrs, options);
-          if (!model) continue;
-          toAdd.push(model);
-          this._addReference(model, options);
+          model = models[i] = this._prepareModel(model, options);
+          if (model) {
+            toAdd.push(model);
+            this._addReference(model, options);
+            modelMap[model.cid] = true;
+            set.push(model);
+          }
         }
-
-        // Do not add multiple models with the same `id`.
-        model = existing || model;
-        if (order && (model.isNew() || !modelMap[model.id])) order.push(model);
-        modelMap[model.id] = true;
       }
 
-      // Remove nonexistent models if appropriate.
+      // Remove stale models.
       if (remove) {
-        for (i = 0, l = this.length; i < l; ++i) {
-          if (!modelMap[(model = this.models[i]).cid]) toRemove.push(model);
+        for (i = 0; i < this.length; i++) {
+          model = this.models[i];
+          if (!modelMap[model.cid]) toRemove.push(model);
         }
-        if (toRemove.length) this.remove(toRemove, options);
+        if (toRemove.length) this._removeModels(toRemove, options);
       }
 
       // See if sorting is needed, update `length` and splice in new models.
-      if (toAdd.length || (order && order.length)) {
+      var orderChanged = false;
+      var replace = !sortable && add && remove;
+      if (set.length && replace) {
+        orderChanged = this.length != set.length || _.some(this.models, function(model, index) {
+          return model !== set[index];
+        });
+        this.models.length = 0;
+        splice(this.models, set, 0);
+        this.length = this.models.length;
+      } else if (toAdd.length) {
         if (sortable) sort = true;
-        this.length += toAdd.length;
-        if (at != null) {
-          for (i = 0, l = toAdd.length; i < l; i++) {
-            this.models.splice(at + i, 0, toAdd[i]);
-          }
-        } else {
-          if (order) this.models.length = 0;
-          var orderedModels = order || toAdd;
-          for (i = 0, l = orderedModels.length; i < l; i++) {
-            this.models.push(orderedModels[i]);
-          }
-        }
+        splice(this.models, toAdd, at == null ? this.length : at);
+        this.length = this.models.length;
       }
 
       // Silently sort the collection if appropriate.
@@ -745,10 +907,13 @@
 
       // Unless silenced, it's time to fire all appropriate add/sort events.
       if (!options.silent) {
-        for (i = 0, l = toAdd.length; i < l; i++) {
-          (model = toAdd[i]).trigger('add', model, this, options);
+        for (i = 0; i < toAdd.length; i++) {
+          if (at != null) options.index = at + i;
+          model = toAdd[i];
+          model.trigger('add', model, this, options);
         }
-        if (sort || (order && order.length)) this.trigger('sort', this, options);
+        if (sort || orderChanged) this.trigger('sort', this, options);
+        if (toAdd.length || toRemove.length) this.trigger('update', this, options);
       }
 
       // Return the added (or merged) model (or models).
@@ -760,8 +925,8 @@
     // any granular `add` or `remove` events. Fires `reset` when finished.
     // Useful for bulk operations and optimizations.
     reset: function(models, options) {
-      options || (options = {});
-      for (var i = 0, l = this.models.length; i < l; i++) {
+      options = options ? _.clone(options) : {};
+      for (var i = 0; i < this.models.length; i++) {
         this._removeReference(this.models[i], options);
       }
       options.previousModels = this.models;
@@ -779,8 +944,7 @@
     // Remove a model from the end of the collection.
     pop: function(options) {
       var model = this.at(this.length - 1);
-      this.remove(model, options);
-      return model;
+      return this.remove(model, options);
     },
 
     // Add a model to the beginning of the collection.
@@ -791,8 +955,7 @@
     // Remove a model from the beginning of the collection.
     shift: function(options) {
       var model = this.at(0);
-      this.remove(model, options);
-      return model;
+      return this.remove(model, options);
     },
 
     // Slice out a sub-array of models from the collection.
@@ -803,24 +966,20 @@
     // Get a model from the set by id.
     get: function(obj) {
       if (obj == null) return void 0;
-      return this._byId[obj] || this._byId[obj.id] || this._byId[obj.cid];
+      var id = this.modelId(this._isModel(obj) ? obj.attributes : obj);
+      return this._byId[obj] || this._byId[id] || this._byId[obj.cid];
     },
 
     // Get the model at the given index.
     at: function(index) {
+      if (index < 0) index += this.length;
       return this.models[index];
     },
 
     // Return models with matching attributes. Useful for simple cases of
     // `filter`.
     where: function(attrs, first) {
-      if (_.isEmpty(attrs)) return first ? void 0 : [];
-      return this[first ? 'find' : 'filter'](function(model) {
-        for (var key in attrs) {
-          if (attrs[key] !== model.get(key)) return false;
-        }
-        return true;
-      });
+      return this[first ? 'find' : 'filter'](attrs);
     },
 
     // Return the first model with matching attributes. Useful for simple cases
@@ -833,16 +992,19 @@
     // normal circumstances, as the set will maintain sort order as each item
     // is added.
     sort: function(options) {
-      if (!this.comparator) throw new Error('Cannot sort a set without a comparator');
+      var comparator = this.comparator;
+      if (!comparator) throw new Error('Cannot sort a set without a comparator');
       options || (options = {});
 
+      var length = comparator.length;
+      if (_.isFunction(comparator)) comparator = _.bind(comparator, this);
+
       // Run sort based on type of `comparator`.
-      if (_.isString(this.comparator) || this.comparator.length === 1) {
-        this.models = this.sortBy(this.comparator, this);
+      if (length === 1 || _.isString(comparator)) {
+        this.models = this.sortBy(comparator);
       } else {
-        this.models.sort(_.bind(this.comparator, this));
+        this.models.sort(comparator);
       }
-
       if (!options.silent) this.trigger('sort', this, options);
       return this;
     },
@@ -856,14 +1018,13 @@
     // collection when they arrive. If `reset: true` is passed, the response
     // data will be passed through the `reset` method instead of `set`.
     fetch: function(options) {
-      options = options ? _.clone(options) : {};
-      if (options.parse === void 0) options.parse = true;
+      options = _.extend({parse: true}, options);
       var success = options.success;
       var collection = this;
       options.success = function(resp) {
         var method = options.reset ? 'reset' : 'set';
         collection[method](resp, options);
-        if (success) success(collection, resp, options);
+        if (success) success.call(options.context, collection, resp, options);
         collection.trigger('sync', collection, resp, options);
       };
       wrapError(this, options);
@@ -875,13 +1036,15 @@
     // wait for the server to agree.
     create: function(model, options) {
       options = options ? _.clone(options) : {};
-      if (!(model = this._prepareModel(model, options))) return false;
-      if (!options.wait) this.add(model, options);
+      var wait = options.wait;
+      model = this._prepareModel(model, options);
+      if (!model) return false;
+      if (!wait) this.add(model, options);
       var collection = this;
       var success = options.success;
-      options.success = function(model, resp) {
-        if (options.wait) collection.add(model, options);
-        if (success) success(model, resp, options);
+      options.success = function(model, resp, callbackOpts) {
+        if (wait) collection.add(model, callbackOpts);
+        if (success) success.call(callbackOpts.context, model, resp, callbackOpts);
       };
       model.save(null, options);
       return model;
@@ -895,7 +1058,15 @@
 
     // Create a new collection with an identical list of models as this one.
     clone: function() {
-      return new this.constructor(this.models);
+      return new this.constructor(this.models, {
+        model: this.model,
+        comparator: this.comparator
+      });
+    },
+
+    // Define how to uniquely identify models in the collection.
+    modelId: function (attrs) {
+      return attrs[this.model.prototype.idAttribute || 'id'];
     },
 
     // Private method to reset all internal state. Called when the collection
@@ -909,7 +1080,10 @@
     // Prepare a hash of attributes (or other model) to be added to this
     // collection.
     _prepareModel: function(attrs, options) {
-      if (attrs instanceof Model) return attrs;
+      if (this._isModel(attrs)) {
+        if (!attrs.collection) attrs.collection = this;
+        return attrs;
+      }
       options = options ? _.clone(options) : {};
       options.collection = this;
       var model = new this.model(attrs, options);
@@ -918,16 +1092,47 @@
       return false;
     },
 
+    // Internal method called by both remove and set.
+    _removeModels: function(models, options) {
+      var removed = [];
+      for (var i = 0; i < models.length; i++) {
+        var model = this.get(models[i]);
+        if (!model) continue;
+
+        var index = this.indexOf(model);
+        this.models.splice(index, 1);
+        this.length--;
+
+        if (!options.silent) {
+          options.index = index;
+          model.trigger('remove', model, this, options);
+        }
+
+        removed.push(model);
+        this._removeReference(model, options);
+      }
+      return removed.length ? removed : false;
+    },
+
+    // Method for checking whether an object should be considered a model for
+    // the purposes of adding to the collection.
+    _isModel: function (model) {
+      return model instanceof Model;
+    },
+
     // Internal method to create a model's ties to a collection.
     _addReference: function(model, options) {
       this._byId[model.cid] = model;
-      if (model.id != null) this._byId[model.id] = model;
-      if (!model.collection) model.collection = this;
+      var id = this.modelId(model.attributes);
+      if (id != null) this._byId[id] = model;
       model.on('all', this._onModelEvent, this);
     },
 
     // Internal method to sever a model's ties to a collection.
     _removeReference: function(model, options) {
+      delete this._byId[model.cid];
+      var id = this.modelId(model.attributes);
+      if (id != null) delete this._byId[id];
       if (this === model.collection) delete model.collection;
       model.off('all', this._onModelEvent, this);
     },
@@ -939,9 +1144,13 @@
     _onModelEvent: function(event, model, collection, options) {
       if ((event === 'add' || event === 'remove') && collection !== this) return;
       if (event === 'destroy') this.remove(model, options);
-      if (model && event === 'change:' + model.idAttribute) {
-        delete this._byId[model.previous(model.idAttribute)];
-        if (model.id != null) this._byId[model.id] = model;
+      if (event === 'change') {
+        var prevId = this.modelId(model.previousAttributes());
+        var id = this.modelId(model.attributes);
+        if (prevId !== id) {
+          if (prevId != null) delete this._byId[prevId];
+          if (id != null) this._byId[id] = model;
+        }
       }
       this.trigger.apply(this, arguments);
     }
@@ -951,34 +1160,17 @@
   // Underscore methods that we want to implement on the Collection.
   // 90% of the core usefulness of Backbone Collections is actually implemented
   // right here:
-  var methods = ['forEach', 'each', 'map', 'collect', 'reduce', 'foldl',
-    'inject', 'reduceRight', 'foldr', 'find', 'detect', 'filter', 'select',
-    'reject', 'every', 'all', 'some', 'any', 'include', 'contains', 'invoke',
-    'max', 'min', 'toArray', 'size', 'first', 'head', 'take', 'initial', 'rest',
-    'tail', 'drop', 'last', 'without', 'difference', 'indexOf', 'shuffle',
-    'lastIndexOf', 'isEmpty', 'chain', 'sample'];
+  var collectionMethods = { forEach: 3, each: 3, map: 3, collect: 3, reduce: 4,
+      foldl: 4, inject: 4, reduceRight: 4, foldr: 4, find: 3, detect: 3, filter: 3,
+      select: 3, reject: 3, every: 3, all: 3, some: 3, any: 3, include: 3, includes: 3,
+      contains: 3, invoke: 0, max: 3, min: 3, toArray: 1, size: 1, first: 3,
+      head: 3, take: 3, initial: 3, rest: 3, tail: 3, drop: 3, last: 3,
+      without: 0, difference: 0, indexOf: 3, shuffle: 1, lastIndexOf: 3,
+      isEmpty: 1, chain: 1, sample: 3, partition: 3, groupBy: 3, countBy: 3,
+      sortBy: 3, indexBy: 3};
 
   // Mix in each Underscore method as a proxy to `Collection#models`.
-  _.each(methods, function(method) {
-    Collection.prototype[method] = function() {
-      var args = slice.call(arguments);
-      args.unshift(this.models);
-      return _[method].apply(_, args);
-    };
-  });
-
-  // Underscore methods that take a property name as an argument.
-  var attributeMethods = ['groupBy', 'countBy', 'sortBy', 'indexBy'];
-
-  // Use attributes instead of properties.
-  _.each(attributeMethods, function(method) {
-    Collection.prototype[method] = function(value, context) {
-      var iterator = _.isFunction(value) ? value : function(model) {
-        return model.get(value);
-      };
-      return _[method](this.models, iterator, context);
-    };
-  });
+  addUnderscoreMethods(Collection, collectionMethods, 'models');
 
   // Backbone.View
   // -------------
@@ -995,17 +1187,15 @@
   // if an existing element is not provided...
   var View = Backbone.View = function(options) {
     this.cid = _.uniqueId('view');
-    options || (options = {});
     _.extend(this, _.pick(options, viewOptions));
     this._ensureElement();
     this.initialize.apply(this, arguments);
-    this.delegateEvents();
   };
 
   // Cached regex to split keys for `delegate`.
   var delegateEventSplitter = /^(\S+)\s*(.*)$/;
 
-  // List of view options to be merged as properties.
+  // List of view options to be set as properties.
   var viewOptions = ['model', 'collection', 'el', 'id', 'attributes', 'className', 'tagName', 'events'];
 
   // Set up all inheritable **Backbone.View** properties and methods.
@@ -1034,19 +1224,35 @@
     // Remove this view by taking the element out of the DOM, and removing any
     // applicable Backbone.Events listeners.
     remove: function() {
-      this.$el.remove();
+      this._removeElement();
       this.stopListening();
       return this;
     },
 
-    // Change the view's element (`this.el` property), including event
-    // re-delegation.
-    setElement: function(element, delegate) {
-      if (this.$el) this.undelegateEvents();
-      this.$el = element instanceof Backbone.$ ? element : Backbone.$(element);
+    // Remove this view's element from the document and all event listeners
+    // attached to it. Exposed for subclasses using an alternative DOM
+    // manipulation API.
+    _removeElement: function() {
+      this.$el.remove();
+    },
+
+    // Change the view's element (`this.el` property) and re-delegate the
+    // view's events on the new element.
+    setElement: function(element) {
+      this.undelegateEvents();
+      this._setElement(element);
+      this.delegateEvents();
+      return this;
+    },
+
+    // Creates the `this.el` and `this.$el` references for this view using the
+    // given `el`. `el` can be a CSS selector or an HTML string, a jQuery
+    // context or an element. Subclasses can override this to utilize an
+    // alternative DOM manipulation API and are only required to set the
+    // `this.el` property.
+    _setElement: function(el) {
+      this.$el = el instanceof Backbone.$ ? el : Backbone.$(el);
       this.el = this.$el[0];
-      if (delegate !== false) this.delegateEvents();
-      return this;
     },
 
     // Set callbacks, where `this.events` is a hash of
@@ -1062,37 +1268,49 @@
     // pairs. Callbacks will be bound to the view, with `this` set properly.
     // Uses event delegation for efficiency.
     // Omitting the selector binds the event to `this.el`.
-    // This only works for delegate-able events: not `focus`, `blur`, and
-    // not `change`, `submit`, and `reset` in Internet Explorer.
     delegateEvents: function(events) {
-      if (!(events || (events = _.result(this, 'events')))) return this;
+      events || (events = _.result(this, 'events'));
+      if (!events) return this;
       this.undelegateEvents();
       for (var key in events) {
         var method = events[key];
-        if (!_.isFunction(method)) method = this[events[key]];
+        if (!_.isFunction(method)) method = this[method];
         if (!method) continue;
-
         var match = key.match(delegateEventSplitter);
-        var eventName = match[1], selector = match[2];
-        method = _.bind(method, this);
-        eventName += '.delegateEvents' + this.cid;
-        if (selector === '') {
-          this.$el.on(eventName, method);
-        } else {
-          this.$el.on(eventName, selector, method);
-        }
+        this.delegate(match[1], match[2], _.bind(method, this));
       }
       return this;
     },
 
-    // Clears all callbacks previously bound to the view with `delegateEvents`.
+    // Add a single event listener to the view's element (or a child element
+    // using `selector`). This only works for delegate-able events: not `focus`,
+    // `blur`, and not `change`, `submit`, and `reset` in Internet Explorer.
+    delegate: function(eventName, selector, listener) {
+      this.$el.on(eventName + '.delegateEvents' + this.cid, selector, listener);
+      return this;
+    },
+
+    // Clears all callbacks previously bound to the view by `delegateEvents`.
     // You usually don't need to use this, but may wish to if you have multiple
     // Backbone views attached to the same DOM element.
     undelegateEvents: function() {
-      this.$el.off('.delegateEvents' + this.cid);
+      if (this.$el) this.$el.off('.delegateEvents' + this.cid);
       return this;
     },
 
+    // A finer-grained `undelegateEvents` for removing a single delegated event.
+    // `selector` and `listener` are both optional.
+    undelegate: function(eventName, selector, listener) {
+      this.$el.off(eventName + '.delegateEvents' + this.cid, selector, listener);
+      return this;
+    },
+
+    // Produces a DOM element to be assigned to your view. Exposed for
+    // subclasses using an alternative DOM manipulation API.
+    _createElement: function(tagName) {
+      return document.createElement(tagName);
+    },
+
     // Ensure that the View has a DOM element to render into.
     // If `this.el` is a string, pass it through `$()`, take the first
     // matching element, and re-assign it to `el`. Otherwise, create
@@ -1102,11 +1320,17 @@
         var attrs = _.extend({}, _.result(this, 'attributes'));
         if (this.id) attrs.id = _.result(this, 'id');
         if (this.className) attrs['class'] = _.result(this, 'className');
-        var $el = Backbone.$('<' + _.result(this, 'tagName') + '>').attr(attrs);
-        this.setElement($el, false);
+        this.setElement(this._createElement(_.result(this, 'tagName')));
+        this._setAttributes(attrs);
       } else {
-        this.setElement(_.result(this, 'el'), false);
+        this.setElement(_.result(this, 'el'));
       }
+    },
+
+    // Set attributes from a hash on this view's element.  Exposed for
+    // subclasses using an alternative DOM manipulation API.
+    _setAttributes: function(attributes) {
+      this.$el.attr(attributes);
     }
 
   });
@@ -1175,14 +1399,13 @@
       params.processData = false;
     }
 
-    // If we're sending a `PATCH` request, and we're in an old Internet Explorer
-    // that still has ActiveX enabled by default, override jQuery to use that
-    // for XHR instead. Remove this line when jQuery supports `PATCH` on IE8.
-    if (params.type === 'PATCH' && noXhrPatch) {
-      params.xhr = function() {
-        return new ActiveXObject("Microsoft.XMLHTTP");
-      };
-    }
+    // Pass along `textStatus` and `errorThrown` from jQuery.
+    var error = options.error;
+    options.error = function(xhr, textStatus, errorThrown) {
+      options.textStatus = textStatus;
+      options.errorThrown = errorThrown;
+      if (error) error.call(options.context, xhr, textStatus, errorThrown);
+    };
 
     // Make the request, allowing the user to override any Ajax options.
     var xhr = options.xhr = Backbone.ajax(_.extend(params, options));
@@ -1190,10 +1413,6 @@
     return xhr;
   };
 
-  var noXhrPatch =
-    typeof window !== 'undefined' && !!window.ActiveXObject &&
-      !(window.XMLHttpRequest && (new XMLHttpRequest).dispatchEvent);
-
   // Map from CRUD to HTTP for our default `Backbone.sync` implementation.
   var methodMap = {
     'create': 'POST',
@@ -1251,17 +1470,18 @@
       var router = this;
       Backbone.history.route(route, function(fragment) {
         var args = router._extractParameters(route, fragment);
-        router.execute(callback, args);
-        router.trigger.apply(router, ['route:' + name].concat(args));
-        router.trigger('route', name, args);
-        Backbone.history.trigger('route', router, name, args);
+        if (router.execute(callback, args, name) !== false) {
+          router.trigger.apply(router, ['route:' + name].concat(args));
+          router.trigger('route', name, args);
+          Backbone.history.trigger('route', router, name, args);
+        }
       });
       return this;
     },
 
     // Execute a route handler with the provided parameters.  This is an
     // excellent place to do pre-route setup or post-route cleanup.
-    execute: function(callback, args) {
+    execute: function(callback, args, name) {
       if (callback) callback.apply(this, args);
     },
 
@@ -1319,7 +1539,7 @@
   // falls back to polling.
   var History = Backbone.History = function() {
     this.handlers = [];
-    _.bindAll(this, 'checkUrl');
+    this.checkUrl = _.bind(this.checkUrl, this);
 
     // Ensure that `History` can be used outside of the browser.
     if (typeof window !== 'undefined') {
@@ -1334,12 +1554,6 @@
   // Cached regex for stripping leading and trailing slashes.
   var rootStripper = /^\/+|\/+$/g;
 
-  // Cached regex for detecting MSIE.
-  var isExplorer = /msie [\w.]+/;
-
-  // Cached regex for removing a trailing slash.
-  var trailingSlash = /\/$/;
-
   // Cached regex for stripping urls of hash.
   var pathStripper = /#.*$/;
 
@@ -1355,7 +1569,29 @@
 
     // Are we at the app root?
     atRoot: function() {
-      return this.location.pathname.replace(/[^\/]$/, '$&/') === this.root;
+      var path = this.location.pathname.replace(/[^\/]$/, '$&/');
+      return path === this.root && !this.getSearch();
+    },
+
+    // Does the pathname match the root?
+    matchRoot: function() {
+      var path = this.decodeFragment(this.location.pathname);
+      var root = path.slice(0, this.root.length - 1) + '/';
+      return root === this.root;
+    },
+
+    // Unicode characters in `location.pathname` are percent encoded so they're
+    // decoded for comparison. `%25` should not be decoded since it may be part
+    // of an encoded parameter.
+    decodeFragment: function(fragment) {
+      return decodeURI(fragment.replace(/%25/g, '%2525'));
+    },
+
+    // In IE6, the hash fragment and search params are incorrect if the
+    // fragment contains `?`.
+    getSearch: function() {
+      var match = this.location.href.replace(/#.*/, '').match(/\?.+/);
+      return match ? match[0] : '';
     },
 
     // Gets the true hash value. Cannot use location.hash directly due to bug
@@ -1365,14 +1601,19 @@
       return match ? match[1] : '';
     },
 
-    // Get the cross-browser normalized URL fragment, either from the URL,
-    // the hash, or the override.
-    getFragment: function(fragment, forcePushState) {
+    // Get the pathname and search params, without the root.
+    getPath: function() {
+      var path = this.decodeFragment(
+        this.location.pathname + this.getSearch()
+      ).slice(this.root.length - 1);
+      return path.charAt(0) === '/' ? path.slice(1) : path;
+    },
+
+    // Get the cross-browser normalized URL fragment from the path or hash.
+    getFragment: function(fragment) {
       if (fragment == null) {
-        if (this._hasPushState || !this._wantsHashChange || forcePushState) {
-          fragment = decodeURI(this.location.pathname + this.location.search);
-          var root = this.root.replace(trailingSlash, '');
-          if (!fragment.indexOf(root)) fragment = fragment.slice(root.length);
+        if (this._usePushState || !this._wantsHashChange) {
+          fragment = this.getPath();
         } else {
           fragment = this.getHash();
         }
@@ -1383,7 +1624,7 @@
     // Start the hash change handling, returning `true` if the current URL matches
     // an existing route, and `false` otherwise.
     start: function(options) {
-      if (History.started) throw new Error("Backbone.history has already been started");
+      if (History.started) throw new Error('Backbone.history has already been started');
       History.started = true;
 
       // Figure out the initial configuration. Do we need an iframe?
@@ -1391,36 +1632,16 @@
       this.options          = _.extend({root: '/'}, this.options, options);
       this.root             = this.options.root;
       this._wantsHashChange = this.options.hashChange !== false;
+      this._hasHashChange   = 'onhashchange' in window && (document.documentMode === void 0 || document.documentMode > 7);
+      this._useHashChange   = this._wantsHashChange && this._hasHashChange;
       this._wantsPushState  = !!this.options.pushState;
-      this._hasPushState    = !!(this.options.pushState && this.history && this.history.pushState);
-      var fragment          = this.getFragment();
-      var docMode           = document.documentMode;
-      var oldIE             = (isExplorer.exec(navigator.userAgent.toLowerCase()) && (!docMode || docMode <= 7));
+      this._hasPushState    = !!(this.history && this.history.pushState);
+      this._usePushState    = this._wantsPushState && this._hasPushState;
+      this.fragment         = this.getFragment();
 
       // Normalize root to always include a leading and trailing slash.
       this.root = ('/' + this.root + '/').replace(rootStripper, '/');
 
-      if (oldIE && this._wantsHashChange) {
-        var frame = Backbone.$('<iframe src="javascript:0" tabindex="-1">');
-        this.iframe = frame.hide().appendTo('body')[0].contentWindow;
-        this.navigate(fragment);
-      }
-
-      // Depending on whether we're using pushState or hashes, and whether
-      // 'onhashchange' is supported, determine how we check the URL state.
-      if (this._hasPushState) {
-        Backbone.$(window).on('popstate', this.checkUrl);
-      } else if (this._wantsHashChange && ('onhashchange' in window) && !oldIE) {
-        Backbone.$(window).on('hashchange', this.checkUrl);
-      } else if (this._wantsHashChange) {
-        this._checkUrlInterval = setInterval(this.checkUrl, this.interval);
-      }
-
-      // Determine if we need to change the base url, for a pushState link
-      // opened by a non-pushState browser.
-      this.fragment = fragment;
-      var loc = this.location;
-
       // Transition from hashChange to pushState or vice versa if both are
       // requested.
       if (this._wantsHashChange && this._wantsPushState) {
@@ -1428,27 +1649,75 @@
         // If we've started off with a route from a `pushState`-enabled
         // browser, but we're currently in a browser that doesn't support it...
         if (!this._hasPushState && !this.atRoot()) {
-          this.fragment = this.getFragment(null, true);
-          this.location.replace(this.root + '#' + this.fragment);
+          var root = this.root.slice(0, -1) || '/';
+          this.location.replace(root + '#' + this.getPath());
           // Return immediately as browser will do redirect to new url
           return true;
 
         // Or if we've started out with a hash-based route, but we're currently
         // in a browser where it could be `pushState`-based instead...
-        } else if (this._hasPushState && this.atRoot() && loc.hash) {
-          this.fragment = this.getHash().replace(routeStripper, '');
-          this.history.replaceState({}, document.title, this.root + this.fragment);
+        } else if (this._hasPushState && this.atRoot()) {
+          this.navigate(this.getHash(), {replace: true});
         }
 
       }
 
+      // Proxy an iframe to handle location events if the browser doesn't
+      // support the `hashchange` event, HTML5 history, or the user wants
+      // `hashChange` but not `pushState`.
+      if (!this._hasHashChange && this._wantsHashChange && !this._usePushState) {
+        this.iframe = document.createElement('iframe');
+        this.iframe.src = 'javascript:0';
+        this.iframe.style.display = 'none';
+        this.iframe.tabIndex = -1;
+        var body = document.body;
+        // Using `appendChild` will throw on IE < 9 if the document is not ready.
+        var iWindow = body.insertBefore(this.iframe, body.firstChild).contentWindow;
+        iWindow.document.open();
+        iWindow.document.close();
+        iWindow.location.hash = '#' + this.fragment;
+      }
+
+      // Add a cross-platform `addEventListener` shim for older browsers.
+      var addEventListener = window.addEventListener || function (eventName, listener) {
+        return attachEvent('on' + eventName, listener);
+      };
+
+      // Depending on whether we're using pushState or hashes, and whether
+      // 'onhashchange' is supported, determine how we check the URL state.
+      if (this._usePushState) {
+        addEventListener('popstate', this.checkUrl, false);
+      } else if (this._useHashChange && !this.iframe) {
+        addEventListener('hashchange', this.checkUrl, false);
+      } else if (this._wantsHashChange) {
+        this._checkUrlInterval = setInterval(this.checkUrl, this.interval);
+      }
+
       if (!this.options.silent) return this.loadUrl();
     },
 
     // Disable Backbone.history, perhaps temporarily. Not useful in a real app,
     // but possibly useful for unit testing Routers.
     stop: function() {
-      Backbone.$(window).off('popstate', this.checkUrl).off('hashchange', this.checkUrl);
+      // Add a cross-platform `removeEventListener` shim for older browsers.
+      var removeEventListener = window.removeEventListener || function (eventName, listener) {
+        return detachEvent('on' + eventName, listener);
+      };
+
+      // Remove window listeners.
+      if (this._usePushState) {
+        removeEventListener('popstate', this.checkUrl, false);
+      } else if (this._useHashChange && !this.iframe) {
+        removeEventListener('hashchange', this.checkUrl, false);
+      }
+
+      // Clean up the iframe if necessary.
+      if (this.iframe) {
+        document.body.removeChild(this.iframe);
+        this.iframe = null;
+      }
+
+      // Some environments will throw when clearing an undefined interval.
       if (this._checkUrlInterval) clearInterval(this._checkUrlInterval);
       History.started = false;
     },
@@ -1463,9 +1732,13 @@
     // calls `loadUrl`, normalizing across the hidden iframe.
     checkUrl: function(e) {
       var current = this.getFragment();
+
+      // If the user pressed the back button, the iframe's hash will have
+      // changed and we should use that for comparison.
       if (current === this.fragment && this.iframe) {
-        current = this.getFragment(this.getHash(this.iframe));
+        current = this.getHash(this.iframe.contentWindow);
       }
+
       if (current === this.fragment) return false;
       if (this.iframe) this.navigate(current);
       this.loadUrl();
@@ -1475,8 +1748,10 @@
     // match, returns `true`. If no defined routes matches the fragment,
     // returns `false`.
     loadUrl: function(fragment) {
+      // If the root doesn't match, no routes can match either.
+      if (!this.matchRoot()) return false;
       fragment = this.fragment = this.getFragment(fragment);
-      return _.any(this.handlers, function(handler) {
+      return _.some(this.handlers, function(handler) {
         if (handler.route.test(fragment)) {
           handler.callback(fragment);
           return true;
@@ -1495,31 +1770,42 @@
       if (!History.started) return false;
       if (!options || options === true) options = {trigger: !!options};
 
-      var url = this.root + (fragment = this.getFragment(fragment || ''));
+      // Normalize the fragment.
+      fragment = this.getFragment(fragment || '');
 
-      // Strip the hash for matching.
-      fragment = fragment.replace(pathStripper, '');
+      // Don't include a trailing slash on the root.
+      var root = this.root;
+      if (fragment === '' || fragment.charAt(0) === '?') {
+        root = root.slice(0, -1) || '/';
+      }
+      var url = root + fragment;
+
+      // Strip the hash and decode for matching.
+      fragment = this.decodeFragment(fragment.replace(pathStripper, ''));
 
       if (this.fragment === fragment) return;
       this.fragment = fragment;
 
-      // Don't include a trailing slash on the root.
-      if (fragment === '' && url !== '/') url = url.slice(0, -1);
-
       // If pushState is available, we use it to set the fragment as a real URL.
-      if (this._hasPushState) {
+      if (this._usePushState) {
         this.history[options.replace ? 'replaceState' : 'pushState']({}, document.title, url);
 
       // If hash changes haven't been explicitly disabled, update the hash
       // fragment to store history.
       } else if (this._wantsHashChange) {
         this._updateHash(this.location, fragment, options.replace);
-        if (this.iframe && (fragment !== this.getFragment(this.getHash(this.iframe)))) {
+        if (this.iframe && (fragment !== this.getHash(this.iframe.contentWindow))) {
+          var iWindow = this.iframe.contentWindow;
+
           // Opening and closing the iframe tricks IE7 and earlier to push a
           // history entry on hash-tag change.  When replace is true, we don't
           // want this.
-          if(!options.replace) this.iframe.document.open().close();
-          this._updateHash(this.iframe.location, fragment, options.replace);
+          if (!options.replace) {
+            iWindow.document.open();
+            iWindow.document.close();
+          }
+
+          this._updateHash(iWindow.location, fragment, options.replace);
         }
 
       // If you've told us that you explicitly don't want fallback hashchange-
@@ -1550,7 +1836,7 @@
   // Helpers
   // -------
 
-  // Helper function to correctly set up the prototype chain, for subclasses.
+  // Helper function to correctly set up the prototype chain for subclasses.
   // Similar to `goog.inherits`, but uses a hash of prototype properties and
   // class properties to be extended.
   var extend = function(protoProps, staticProps) {
@@ -1559,7 +1845,7 @@
 
     // The constructor function for the new subclass is either defined by you
     // (the "constructor" property in your `extend` definition), or defaulted
-    // by us to simply call the parent's constructor.
+    // by us to simply call the parent constructor.
     if (protoProps && _.has(protoProps, 'constructor')) {
       child = protoProps.constructor;
     } else {
@@ -1570,7 +1856,7 @@
     _.extend(child, parent, staticProps);
 
     // Set the prototype chain to inherit from `parent`, without calling
-    // `parent`'s constructor function.
+    // `parent` constructor function.
     var Surrogate = function(){ this.constructor = child; };
     Surrogate.prototype = parent.prototype;
     child.prototype = new Surrogate;
@@ -1598,7 +1884,7 @@
   var wrapError = function(model, options) {
     var error = options.error;
     options.error = function(resp) {
-      if (error) error(model, resp, options);
+      if (error) error.call(options.context, model, resp, options);
       model.trigger('error', model, resp, options);
     };
   };
--- a/server/php/basic/public_html/static/lib/lodash/lodash.js	Wed Sep 09 15:05:30 2015 +0200
+++ b/server/php/basic/public_html/static/lib/lodash/lodash.js	Wed Sep 09 15:18:53 2015 +0200
@@ -1,175 +1,350 @@
 /**
  * @license
- * Lo-Dash 2.4.2 (Custom Build) <https://lodash.com/>
- * Build: `lodash modern -o ./dist/lodash.js`
- * Copyright 2012-2013 The Dojo Foundation <http://dojofoundation.org/>
- * Based on Underscore.js 1.5.2 <http://underscorejs.org/LICENSE>
- * Copyright 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
+ * lodash 3.10.1 (Custom Build) <https://lodash.com/>
+ * Build: `lodash modern -o ./lodash.js`
+ * Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
+ * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
+ * Copyright 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
  * Available under MIT license <https://lodash.com/license>
  */
 ;(function() {
 
-  /** Used as a safe reference for `undefined` in pre ES5 environments */
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   var undefined;
 
-  /** Used to pool arrays and objects used internally */
-  var arrayPool = [],
-      objectPool = [];
-
-  /** Used to generate unique IDs */
-  var idCounter = 0;
-
-  /** Used to prefix keys to avoid issues with `__proto__` and properties on `Object.prototype` */
-  var keyPrefix = +new Date + '';
-
-  /** Used as the size when optimizations are enabled for large arrays */
-  var largeArraySize = 75;
-
-  /** Used as the max size of the `arrayPool` and `objectPool` */
-  var maxPoolSize = 40;
-
-  /** Used to detect and test whitespace */
-  var whitespace = (
-    // whitespace
-    ' \t\x0B\f\xA0\ufeff' +
-
-    // line terminators
-    '\n\r\u2028\u2029' +
-
-    // unicode category "Zs" space separators
-    '\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000'
-  );
-
-  /** Used to match empty string literals in compiled template source */
+  /** Used as the semantic version number. */
+  var VERSION = '3.10.1';
+
+  /** Used to compose bitmasks for wrapper metadata. */
+  var BIND_FLAG = 1,
+      BIND_KEY_FLAG = 2,
+      CURRY_BOUND_FLAG = 4,
+      CURRY_FLAG = 8,
+      CURRY_RIGHT_FLAG = 16,
+      PARTIAL_FLAG = 32,
+      PARTIAL_RIGHT_FLAG = 64,
+      ARY_FLAG = 128,
+      REARG_FLAG = 256;
+
+  /** Used as default options for `_.trunc`. */
+  var DEFAULT_TRUNC_LENGTH = 30,
+      DEFAULT_TRUNC_OMISSION = '...';
+
+  /** Used to detect when a function becomes hot. */
+  var HOT_COUNT = 150,
+      HOT_SPAN = 16;
+
+  /** Used as the size to enable large array optimizations. */
+  var LARGE_ARRAY_SIZE = 200;
+
+  /** Used to indicate the type of lazy iteratees. */
+  var LAZY_FILTER_FLAG = 1,
+      LAZY_MAP_FLAG = 2;
+
+  /** Used as the `TypeError` message for "Functions" methods. */
+  var FUNC_ERROR_TEXT = 'Expected a function';
+
+  /** Used as the internal argument placeholder. */
+  var PLACEHOLDER = '__lodash_placeholder__';
+
+  /** `Object#toString` result references. */
+  var argsTag = '[object Arguments]',
+      arrayTag = '[object Array]',
+      boolTag = '[object Boolean]',
+      dateTag = '[object Date]',
+      errorTag = '[object Error]',
+      funcTag = '[object Function]',
+      mapTag = '[object Map]',
+      numberTag = '[object Number]',
+      objectTag = '[object Object]',
+      regexpTag = '[object RegExp]',
+      setTag = '[object Set]',
+      stringTag = '[object String]',
+      weakMapTag = '[object WeakMap]';
+
+  var arrayBufferTag = '[object ArrayBuffer]',
+      float32Tag = '[object Float32Array]',
+      float64Tag = '[object Float64Array]',
+      int8Tag = '[object Int8Array]',
+      int16Tag = '[object Int16Array]',
+      int32Tag = '[object Int32Array]',
+      uint8Tag = '[object Uint8Array]',
+      uint8ClampedTag = '[object Uint8ClampedArray]',
+      uint16Tag = '[object Uint16Array]',
+      uint32Tag = '[object Uint32Array]';
+
+  /** Used to match empty string literals in compiled template source. */
   var reEmptyStringLeading = /\b__p \+= '';/g,
       reEmptyStringMiddle = /\b(__p \+=) '' \+/g,
       reEmptyStringTrailing = /(__e\(.*?\)|\b__t\)) \+\n'';/g;
 
+  /** Used to match HTML entities and HTML characters. */
+  var reEscapedHtml = /&(?:amp|lt|gt|quot|#39|#96);/g,
+      reUnescapedHtml = /[&<>"'`]/g,
+      reHasEscapedHtml = RegExp(reEscapedHtml.source),
+      reHasUnescapedHtml = RegExp(reUnescapedHtml.source);
+
+  /** Used to match template delimiters. */
+  var reEscape = /<%-([\s\S]+?)%>/g,
+      reEvaluate = /<%([\s\S]+?)%>/g,
+      reInterpolate = /<%=([\s\S]+?)%>/g;
+
+  /** Used to match property names within property paths. */
+  var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\n\\]|\\.)*?\1)\]/,
+      reIsPlainProp = /^\w*$/,
+      rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\n\\]|\\.)*?)\2)\]/g;
+
   /**
-   * Used to match ES6 template delimiters
-   * http://people.mozilla.org/~jorendorff/es6-draft.html#sec-literals-string-literals
+   * Used to match `RegExp` [syntax characters](http://ecma-international.org/ecma-262/6.0/#sec-patterns)
+   * and those outlined by [`EscapeRegExpPattern`](http://ecma-international.org/ecma-262/6.0/#sec-escaperegexppattern).
    */
+  var reRegExpChars = /^[:!,]|[\\^$.*+?()[\]{}|\/]|(^[0-9a-fA-Fnrtuvx])|([\n\r\u2028\u2029])/g,
+      reHasRegExpChars = RegExp(reRegExpChars.source);
+
+  /** Used to match [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks). */
+  var reComboMark = /[\u0300-\u036f\ufe20-\ufe23]/g;
+
+  /** Used to match backslashes in property paths. */
+  var reEscapeChar = /\\(\\)?/g;
+
+  /** Used to match [ES template delimiters](http://ecma-international.org/ecma-262/6.0/#sec-template-literal-lexical-components). */
   var reEsTemplate = /\$\{([^\\}]*(?:\\.[^\\}]*)*)\}/g;
 
-  /** Used to match regexp flags from their coerced string values */
+  /** Used to match `RegExp` flags from their coerced string values. */
   var reFlags = /\w*$/;
 
-  /** Used to detected named functions */
-  var reFuncName = /^\s*function[ \n\r\t]+\w/;
-
-  /** Used to match "interpolate" template delimiters */
-  var reInterpolate = /<%=([\s\S]+?)%>/g;
-
-  /** Used to match leading whitespace and zeros to be removed */
-  var reLeadingSpacesAndZeros = RegExp('^[' + whitespace + ']*0+(?=.$)');
-
-  /** Used to ensure capturing order of template delimiters */
+  /** Used to detect hexadecimal string values. */
+  var reHasHexPrefix = /^0[xX]/;
+
+  /** Used to detect host constructors (Safari > 5). */
+  var reIsHostCtor = /^\[object .+?Constructor\]$/;
+
+  /** Used to detect unsigned integer values. */
+  var reIsUint = /^\d+$/;
+
+  /** Used to match latin-1 supplementary letters (excluding mathematical operators). */
+  var reLatin1 = /[\xc0-\xd6\xd8-\xde\xdf-\xf6\xf8-\xff]/g;
+
+  /** Used to ensure capturing order of template delimiters. */
   var reNoMatch = /($^)/;
 
-  /** Used to detect functions containing a `this` reference */
-  var reThis = /\bthis\b/;
-
-  /** Used to match unescaped characters in compiled string literals */
-  var reUnescapedString = /['\n\r\t\u2028\u2029\\]/g;
-
-  /** Used to assign default `context` object properties */
+  /** Used to match unescaped characters in compiled string literals. */
+  var reUnescapedString = /['\n\r\u2028\u2029\\]/g;
+
+  /** Used to match words to create compound words. */
+  var reWords = (function() {
+    var upper = '[A-Z\\xc0-\\xd6\\xd8-\\xde]',
+        lower = '[a-z\\xdf-\\xf6\\xf8-\\xff]+';
+
+    return RegExp(upper + '+(?=' + upper + lower + ')|' + upper + '?' + lower + '|' + upper + '+|[0-9]+', 'g');
+  }());
+
+  /** Used to assign default `context` object properties. */
   var contextProps = [
-    'Array', 'Boolean', 'Date', 'Function', 'Math', 'Number', 'Object',
-    'RegExp', 'String', '_', 'attachEvent', 'clearTimeout', 'isFinite', 'isNaN',
-    'parseInt', 'setTimeout'
+    'Array', 'ArrayBuffer', 'Date', 'Error', 'Float32Array', 'Float64Array',
+    'Function', 'Int8Array', 'Int16Array', 'Int32Array', 'Math', 'Number',
+    'Object', 'RegExp', 'Set', 'String', '_', 'clearTimeout', 'isFinite',
+    'parseFloat', 'parseInt', 'setTimeout', 'TypeError', 'Uint8Array',
+    'Uint8ClampedArray', 'Uint16Array', 'Uint32Array', 'WeakMap'
   ];
 
-  /** Used to make template sourceURLs easier to identify */
-  var templateCounter = 0;
-
-  /** `Object#toString` result shortcuts */
-  var argsClass = '[object Arguments]',
-      arrayClass = '[object Array]',
-      boolClass = '[object Boolean]',
-      dateClass = '[object Date]',
-      funcClass = '[object Function]',
-      numberClass = '[object Number]',
-      objectClass = '[object Object]',
-      regexpClass = '[object RegExp]',
-      stringClass = '[object String]';
-
-  /** Used to identify object classifications that `_.clone` supports */
-  var cloneableClasses = {};
-  cloneableClasses[funcClass] = false;
-  cloneableClasses[argsClass] = cloneableClasses[arrayClass] =
-  cloneableClasses[boolClass] = cloneableClasses[dateClass] =
-  cloneableClasses[numberClass] = cloneableClasses[objectClass] =
-  cloneableClasses[regexpClass] = cloneableClasses[stringClass] = true;
-
-  /** Used as an internal `_.debounce` options object */
-  var debounceOptions = {
-    'leading': false,
-    'maxWait': 0,
-    'trailing': false
+  /** Used to make template sourceURLs easier to identify. */
+  var templateCounter = -1;
+
+  /** Used to identify `toStringTag` values of typed arrays. */
+  var typedArrayTags = {};
+  typedArrayTags[float32Tag] = typedArrayTags[float64Tag] =
+  typedArrayTags[int8Tag] = typedArrayTags[int16Tag] =
+  typedArrayTags[int32Tag] = typedArrayTags[uint8Tag] =
+  typedArrayTags[uint8ClampedTag] = typedArrayTags[uint16Tag] =
+  typedArrayTags[uint32Tag] = true;
+  typedArrayTags[argsTag] = typedArrayTags[arrayTag] =
+  typedArrayTags[arrayBufferTag] = typedArrayTags[boolTag] =
+  typedArrayTags[dateTag] = typedArrayTags[errorTag] =
+  typedArrayTags[funcTag] = typedArrayTags[mapTag] =
+  typedArrayTags[numberTag] = typedArrayTags[objectTag] =
+  typedArrayTags[regexpTag] = typedArrayTags[setTag] =
+  typedArrayTags[stringTag] = typedArrayTags[weakMapTag] = false;
+
+  /** Used to identify `toStringTag` values supported by `_.clone`. */
+  var cloneableTags = {};
+  cloneableTags[argsTag] = cloneableTags[arrayTag] =
+  cloneableTags[arrayBufferTag] = cloneableTags[boolTag] =
+  cloneableTags[dateTag] = cloneableTags[float32Tag] =
+  cloneableTags[float64Tag] = cloneableTags[int8Tag] =
+  cloneableTags[int16Tag] = cloneableTags[int32Tag] =
+  cloneableTags[numberTag] = cloneableTags[objectTag] =
+  cloneableTags[regexpTag] = cloneableTags[stringTag] =
+  cloneableTags[uint8Tag] = cloneableTags[uint8ClampedTag] =
+  cloneableTags[uint16Tag] = cloneableTags[uint32Tag] = true;
+  cloneableTags[errorTag] = cloneableTags[funcTag] =
+  cloneableTags[mapTag] = cloneableTags[setTag] =
+  cloneableTags[weakMapTag] = false;
+
+  /** Used to map latin-1 supplementary letters to basic latin letters. */
+  var deburredLetters = {
+    '\xc0': 'A',  '\xc1': 'A', '\xc2': 'A', '\xc3': 'A', '\xc4': 'A', '\xc5': 'A',
+    '\xe0': 'a',  '\xe1': 'a', '\xe2': 'a', '\xe3': 'a', '\xe4': 'a', '\xe5': 'a',
+    '\xc7': 'C',  '\xe7': 'c',
+    '\xd0': 'D',  '\xf0': 'd',
+    '\xc8': 'E',  '\xc9': 'E', '\xca': 'E', '\xcb': 'E',
+    '\xe8': 'e',  '\xe9': 'e', '\xea': 'e', '\xeb': 'e',
+    '\xcC': 'I',  '\xcd': 'I', '\xce': 'I', '\xcf': 'I',
+    '\xeC': 'i',  '\xed': 'i', '\xee': 'i', '\xef': 'i',
+    '\xd1': 'N',  '\xf1': 'n',
+    '\xd2': 'O',  '\xd3': 'O', '\xd4': 'O', '\xd5': 'O', '\xd6': 'O', '\xd8': 'O',
+    '\xf2': 'o',  '\xf3': 'o', '\xf4': 'o', '\xf5': 'o', '\xf6': 'o', '\xf8': 'o',
+    '\xd9': 'U',  '\xda': 'U', '\xdb': 'U', '\xdc': 'U',
+    '\xf9': 'u',  '\xfa': 'u', '\xfb': 'u', '\xfc': 'u',
+    '\xdd': 'Y',  '\xfd': 'y', '\xff': 'y',
+    '\xc6': 'Ae', '\xe6': 'ae',
+    '\xde': 'Th', '\xfe': 'th',
+    '\xdf': 'ss'
   };
 
-  /** Used as the property descriptor for `__bindData__` */
-  var descriptor = {
-    'configurable': false,
-    'enumerable': false,
-    'value': null,
-    'writable': false
+  /** Used to map characters to HTML entities. */
+  var htmlEscapes = {
+    '&': '&amp;',
+    '<': '&lt;',
+    '>': '&gt;',
+    '"': '&quot;',
+    "'": '&#39;',
+    '`': '&#96;'
   };
 
-  /** Used to determine if values are of the language type Object */
+  /** Used to map HTML entities to characters. */
+  var htmlUnescapes = {
+    '&amp;': '&',
+    '&lt;': '<',
+    '&gt;': '>',
+    '&quot;': '"',
+    '&#39;': "'",
+    '&#96;': '`'
+  };
+
+  /** Used to determine if values are of the language type `Object`. */
   var objectTypes = {
-    'boolean': false,
     'function': true,
-    'object': true,
-    'number': false,
-    'string': false,
-    'undefined': false
+    'object': true
   };
 
-  /** Used to escape characters for inclusion in compiled string literals */
+  /** Used to escape characters for inclusion in compiled regexes. */
+  var regexpEscapes = {
+    '0': 'x30', '1': 'x31', '2': 'x32', '3': 'x33', '4': 'x34',
+    '5': 'x35', '6': 'x36', '7': 'x37', '8': 'x38', '9': 'x39',
+    'A': 'x41', 'B': 'x42', 'C': 'x43', 'D': 'x44', 'E': 'x45', 'F': 'x46',
+    'a': 'x61', 'b': 'x62', 'c': 'x63', 'd': 'x64', 'e': 'x65', 'f': 'x66',
+    'n': 'x6e', 'r': 'x72', 't': 'x74', 'u': 'x75', 'v': 'x76', 'x': 'x78'
+  };
+
+  /** Used to escape characters for inclusion in compiled string literals. */
   var stringEscapes = {
     '\\': '\\',
     "'": "'",
     '\n': 'n',
     '\r': 'r',
-    '\t': 't',
     '\u2028': 'u2028',
     '\u2029': 'u2029'
   };
 
-  /** Used as a reference to the global object */
-  var root = (objectTypes[typeof window] && window) || this;
-
-  /** Detect free variable `exports` */
+  /** Detect free variable `exports`. */
   var freeExports = objectTypes[typeof exports] && exports && !exports.nodeType && exports;
 
-  /** Detect free variable `module` */
+  /** Detect free variable `module`. */
   var freeModule = objectTypes[typeof module] && module && !module.nodeType && module;
 
-  /** Detect the popular CommonJS extension `module.exports` */
+  /** Detect free variable `global` from Node.js. */
+  var freeGlobal = freeExports && freeModule && typeof global == 'object' && global && global.Object && global;
+
+  /** Detect free variable `self`. */
+  var freeSelf = objectTypes[typeof self] && self && self.Object && self;
+
+  /** Detect free variable `window`. */
+  var freeWindow = objectTypes[typeof window] && window && window.Object && window;
+
+  /** Detect the popular CommonJS extension `module.exports`. */
   var moduleExports = freeModule && freeModule.exports === freeExports && freeExports;
 
-  /** Detect free variable `global` from Node.js or Browserified code and use it as `root` */
-  var freeGlobal = objectTypes[typeof global] && global;
-  if (freeGlobal && (freeGlobal.global === freeGlobal || freeGlobal.window === freeGlobal)) {
-    root = freeGlobal;
-  }
+  /**
+   * Used as a reference to the global object.
+   *
+   * The `this` value is used if it's the global object to avoid Greasemonkey's
+   * restricted `window` object, otherwise the `window` object is used.
+   */
+  var root = freeGlobal || ((freeWindow !== (this && this.window)) && freeWindow) || freeSelf || this;
 
   /*--------------------------------------------------------------------------*/
 
   /**
-   * The base implementation of `_.indexOf` without support for binary searches
-   * or `fromIndex` constraints.
+   * The base implementation of `compareAscending` which compares values and
+   * sorts them in ascending order without guaranteeing a stable sort.
+   *
+   * @private
+   * @param {*} value The value to compare.
+   * @param {*} other The other value to compare.
+   * @returns {number} Returns the sort order indicator for `value`.
+   */
+  function baseCompareAscending(value, other) {
+    if (value !== other) {
+      var valIsNull = value === null,
+          valIsUndef = value === undefined,
+          valIsReflexive = value === value;
+
+      var othIsNull = other === null,
+          othIsUndef = other === undefined,
+          othIsReflexive = other === other;
+
+      if ((value > other && !othIsNull) || !valIsReflexive ||
+          (valIsNull && !othIsUndef && othIsReflexive) ||
+          (valIsUndef && othIsReflexive)) {
+        return 1;
+      }
+      if ((value < other && !valIsNull) || !othIsReflexive ||
+          (othIsNull && !valIsUndef && valIsReflexive) ||
+          (othIsUndef && valIsReflexive)) {
+        return -1;
+      }
+    }
+    return 0;
+  }
+
+  /**
+   * The base implementation of `_.findIndex` and `_.findLastIndex` without
+   * support for callback shorthands and `this` binding.
+   *
+   * @private
+   * @param {Array} array The array to search.
+   * @param {Function} predicate The function invoked per iteration.
+   * @param {boolean} [fromRight] Specify iterating from right to left.
+   * @returns {number} Returns the index of the matched value, else `-1`.
+   */
+  function baseFindIndex(array, predicate, fromRight) {
+    var length = array.length,
+        index = fromRight ? length : -1;
+
+    while ((fromRight ? index-- : ++index < length)) {
+      if (predicate(array[index], index, array)) {
+        return index;
+      }
+    }
+    return -1;
+  }
+
+  /**
+   * The base implementation of `_.indexOf` without support for binary searches.
    *
    * @private
    * @param {Array} array The array to search.
    * @param {*} value The value to search for.
-   * @param {number} [fromIndex=0] The index to search from.
-   * @returns {number} Returns the index of the matched value or `-1`.
+   * @param {number} fromIndex The index to search from.
+   * @returns {number} Returns the index of the matched value, else `-1`.
    */
   function baseIndexOf(array, value, fromIndex) {
-    var index = (fromIndex || 0) - 1,
-        length = array ? array.length : 0;
+    if (value !== value) {
+      return indexOfNaN(array, fromIndex);
+    }
+    var index = fromIndex - 1,
+        length = array.length;
 
     while (++index < length) {
       if (array[index] === value) {
@@ -180,266 +355,357 @@
   }
 
   /**
-   * An implementation of `_.contains` for cache objects that mimics the return
-   * signature of `_.indexOf` by returning `0` if the value is found, else `-1`.
+   * The base implementation of `_.isFunction` without support for environments
+   * with incorrect `typeof` results.
+   *
+   * @private
+   * @param {*} value The value to check.
+   * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+   */
+  function baseIsFunction(value) {
+    // Avoid a Chakra JIT bug in compatibility modes of IE 11.
+    // See https://github.com/jashkenas/underscore/issues/1621 for more details.
+    return typeof value == 'function' || false;
+  }
+
+  /**
+   * Converts `value` to a string if it's not one. An empty string is returned
+   * for `null` or `undefined` values.
    *
    * @private
-   * @param {Object} cache The cache object to inspect.
-   * @param {*} value The value to search for.
-   * @returns {number} Returns `0` if `value` is found, else `-1`.
+   * @param {*} value The value to process.
+   * @returns {string} Returns the string.
    */
-  function cacheIndexOf(cache, value) {
-    var type = typeof value;
-    cache = cache.cache;
-
-    if (type == 'boolean' || value == null) {
-      return cache[value] ? 0 : -1;
-    }
-    if (type != 'number' && type != 'string') {
-      type = 'object';
-    }
-    var key = type == 'number' ? value : keyPrefix + value;
-    cache = (cache = cache[type]) && cache[key];
-
-    return type == 'object'
-      ? (cache && baseIndexOf(cache, value) > -1 ? 0 : -1)
-      : (cache ? 0 : -1);
+  function baseToString(value) {
+    return value == null ? '' : (value + '');
+  }
+
+  /**
+   * Used by `_.trim` and `_.trimLeft` to get the index of the first character
+   * of `string` that is not found in `chars`.
+   *
+   * @private
+   * @param {string} string The string to inspect.
+   * @param {string} chars The characters to find.
+   * @returns {number} Returns the index of the first character not found in `chars`.
+   */
+  function charsLeftIndex(string, chars) {
+    var index = -1,
+        length = string.length;
+
+    while (++index < length && chars.indexOf(string.charAt(index)) > -1) {}
+    return index;
   }
 
   /**
-   * Adds a given value to the corresponding cache object.
+   * Used by `_.trim` and `_.trimRight` to get the index of the last character
+   * of `string` that is not found in `chars`.
+   *
+   * @private
+   * @param {string} string The string to inspect.
+   * @param {string} chars The characters to find.
+   * @returns {number} Returns the index of the last character not found in `chars`.
+   */
+  function charsRightIndex(string, chars) {
+    var index = string.length;
+
+    while (index-- && chars.indexOf(string.charAt(index)) > -1) {}
+    return index;
+  }
+
+  /**
+   * Used by `_.sortBy` to compare transformed elements of a collection and stable
+   * sort them in ascending order.
    *
    * @private
-   * @param {*} value The value to add to the cache.
+   * @param {Object} object The object to compare.
+   * @param {Object} other The other object to compare.
+   * @returns {number} Returns the sort order indicator for `object`.
+   */
+  function compareAscending(object, other) {
+    return baseCompareAscending(object.criteria, other.criteria) || (object.index - other.index);
+  }
+
+  /**
+   * Used by `_.sortByOrder` to compare multiple properties of a value to another
+   * and stable sort them.
+   *
+   * If `orders` is unspecified, all valuess are sorted in ascending order. Otherwise,
+   * a value is sorted in ascending order if its corresponding order is "asc", and
+   * descending if "desc".
+   *
+   * @private
+   * @param {Object} object The object to compare.
+   * @param {Object} other The other object to compare.
+   * @param {boolean[]} orders The order to sort by for each property.
+   * @returns {number} Returns the sort order indicator for `object`.
    */
-  function cachePush(value) {
-    var cache = this.cache,
-        type = typeof value;
-
-    if (type == 'boolean' || value == null) {
-      cache[value] = true;
-    } else {
-      if (type != 'number' && type != 'string') {
-        type = 'object';
-      }
-      var key = type == 'number' ? value : keyPrefix + value,
-          typeCache = cache[type] || (cache[type] = {});
-
-      if (type == 'object') {
-        (typeCache[key] || (typeCache[key] = [])).push(value);
-      } else {
-        typeCache[key] = true;
-      }
-    }
+  function compareMultiple(object, other, orders) {
+    var index = -1,
+        objCriteria = object.criteria,
+        othCriteria = other.criteria,
+        length = objCriteria.length,
+        ordersLength = orders.length;
+
+    while (++index < length) {
+      var result = baseCompareAscending(objCriteria[index], othCriteria[index]);
+      if (result) {
+        if (index >= ordersLength) {
+          return result;
+        }
+        var order = orders[index];
+        return result * ((order === 'asc' || order === true) ? 1 : -1);
+      }
+    }
+    // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications
+    // that causes it, under certain circumstances, to provide the same value for
+    // `object` and `other`. See https://github.com/jashkenas/underscore/pull/1247
+    // for more details.
+    //
+    // This also ensures a stable sort in V8 and other engines.
+    // See https://code.google.com/p/v8/issues/detail?id=90 for more details.
+    return object.index - other.index;
   }
 
   /**
-   * Used by `_.max` and `_.min` as the default callback when a given
-   * collection is a string value.
+   * Used by `_.deburr` to convert latin-1 supplementary letters to basic latin letters.
+   *
+   * @private
+   * @param {string} letter The matched letter to deburr.
+   * @returns {string} Returns the deburred letter.
+   */
+  function deburrLetter(letter) {
+    return deburredLetters[letter];
+  }
+
+  /**
+   * Used by `_.escape` to convert characters to HTML entities.
    *
    * @private
-   * @param {string} value The character to inspect.
-   * @returns {number} Returns the code unit of given character.
+   * @param {string} chr The matched character to escape.
+   * @returns {string} Returns the escaped character.
+   */
+  function escapeHtmlChar(chr) {
+    return htmlEscapes[chr];
+  }
+
+  /**
+   * Used by `_.escapeRegExp` to escape characters for inclusion in compiled regexes.
+   *
+   * @private
+   * @param {string} chr The matched character to escape.
+   * @param {string} leadingChar The capture group for a leading character.
+   * @param {string} whitespaceChar The capture group for a whitespace character.
+   * @returns {string} Returns the escaped character.
    */
-  function charAtCallback(value) {
-    return value.charCodeAt(0);
+  function escapeRegExpChar(chr, leadingChar, whitespaceChar) {
+    if (leadingChar) {
+      chr = regexpEscapes[chr];
+    } else if (whitespaceChar) {
+      chr = stringEscapes[chr];
+    }
+    return '\\' + chr;
+  }
+
+  /**
+   * Used by `_.template` to escape characters for inclusion in compiled string literals.
+   *
+   * @private
+   * @param {string} chr The matched character to escape.
+   * @returns {string} Returns the escaped character.
+   */
+  function escapeStringChar(chr) {
+    return '\\' + stringEscapes[chr];
   }
 
   /**
-   * Used by `sortBy` to compare transformed `collection` elements, stable sorting
-   * them in ascending order.
+   * Gets the index at which the first occurrence of `NaN` is found in `array`.
    *
    * @private
-   * @param {Object} a The object to compare to `b`.
-   * @param {Object} b The object to compare to `a`.
-   * @returns {number} Returns the sort order indicator of `1` or `-1`.
+   * @param {Array} array The array to search.
+   * @param {number} fromIndex The index to search from.
+   * @param {boolean} [fromRight] Specify iterating from right to left.
+   * @returns {number} Returns the index of the matched `NaN`, else `-1`.
    */
-  function compareAscending(a, b) {
-    var ac = a.criteria,
-        bc = b.criteria,
-        index = -1,
-        length = ac.length;
-
-    while (++index < length) {
-      var value = ac[index],
-          other = bc[index];
-
-      if (value !== other) {
-        if (value > other || typeof value == 'undefined') {
-          return 1;
-        }
-        if (value < other || typeof other == 'undefined') {
-          return -1;
-        }
-      }
-    }
-    // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications
-    // that causes it, under certain circumstances, to return the same value for
-    // `a` and `b`. See https://github.com/jashkenas/underscore/pull/1247
-    //
-    // This also ensures a stable sort in V8 and other engines.
-    // See http://code.google.com/p/v8/issues/detail?id=90
-    return a.index - b.index;
+  function indexOfNaN(array, fromIndex, fromRight) {
+    var length = array.length,
+        index = fromIndex + (fromRight ? 0 : -1);
+
+    while ((fromRight ? index-- : ++index < length)) {
+      var other = array[index];
+      if (other !== other) {
+        return index;
+      }
+    }
+    return -1;
+  }
+
+  /**
+   * Checks if `value` is object-like.
+   *
+   * @private
+   * @param {*} value The value to check.
+   * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
+   */
+  function isObjectLike(value) {
+    return !!value && typeof value == 'object';
   }
 
   /**
-   * Creates a cache object to optimize linear searches of large arrays.
+   * Used by `trimmedLeftIndex` and `trimmedRightIndex` to determine if a
+   * character code is whitespace.
    *
    * @private
-   * @param {Array} [array=[]] The array to search.
-   * @returns {null|Object} Returns the cache object or `null` if caching should not be used.
+   * @param {number} charCode The character code to inspect.
+   * @returns {boolean} Returns `true` if `charCode` is whitespace, else `false`.
    */
-  function createCache(array) {
+  function isSpace(charCode) {
+    return ((charCode <= 160 && (charCode >= 9 && charCode <= 13) || charCode == 32 || charCode == 160) || charCode == 5760 || charCode == 6158 ||
+      (charCode >= 8192 && (charCode <= 8202 || charCode == 8232 || charCode == 8233 || charCode == 8239 || charCode == 8287 || charCode == 12288 || charCode == 65279)));
+  }
+
+  /**
+   * Replaces all `placeholder` elements in `array` with an internal placeholder
+   * and returns an array of their indexes.
+   *
+   * @private
+   * @param {Array} array The array to modify.
+   * @param {*} placeholder The placeholder to replace.
+   * @returns {Array} Returns the new array of placeholder indexes.
+   */
+  function replaceHolders(array, placeholder) {
     var index = -1,
         length = array.length,
-        first = array[0],
-        mid = array[(length / 2) | 0],
-        last = array[length - 1];
-
-    if (first && typeof first == 'object' &&
-        mid && typeof mid == 'object' && last && typeof last == 'object') {
-      return false;
-    }
-    var cache = getObject();
-    cache['false'] = cache['null'] = cache['true'] = cache['undefined'] = false;
-
-    var result = getObject();
-    result.array = array;
-    result.cache = cache;
-    result.push = cachePush;
+        resIndex = -1,
+        result = [];
 
     while (++index < length) {
-      result.push(array[index]);
+      if (array[index] === placeholder) {
+        array[index] = PLACEHOLDER;
+        result[++resIndex] = index;
+      }
     }
     return result;
   }
 
   /**
-   * Used by `template` to escape characters for inclusion in compiled
-   * string literals.
-   *
-   * @private
-   * @param {string} match The matched character to escape.
-   * @returns {string} Returns the escaped character.
-   */
-  function escapeStringChar(match) {
-    return '\\' + stringEscapes[match];
-  }
-
-  /**
-   * Gets an array from the array pool or creates a new one if the pool is empty.
+   * An implementation of `_.uniq` optimized for sorted arrays without support
+   * for callback shorthands and `this` binding.
    *
    * @private
-   * @returns {Array} The array from the pool.
-   */
-  function getArray() {
-    return arrayPool.pop() || [];
-  }
-
-  /**
-   * Gets an object from the object pool or creates a new one if the pool is empty.
-   *
-   * @private
-   * @returns {Object} The object from the pool.
+   * @param {Array} array The array to inspect.
+   * @param {Function} [iteratee] The function invoked per iteration.
+   * @returns {Array} Returns the new duplicate free array.
    */
-  function getObject() {
-    return objectPool.pop() || {
-      'array': null,
-      'cache': null,
-      'criteria': null,
-      'false': false,
-      'index': 0,
-      'null': false,
-      'number': null,
-      'object': null,
-      'push': null,
-      'string': null,
-      'true': false,
-      'undefined': false,
-      'value': null
-    };
+  function sortedUniq(array, iteratee) {
+    var seen,
+        index = -1,
+        length = array.length,
+        resIndex = -1,
+        result = [];
+
+    while (++index < length) {
+      var value = array[index],
+          computed = iteratee ? iteratee(value, index, array) : value;
+
+      if (!index || seen !== computed) {
+        seen = computed;
+        result[++resIndex] = value;
+      }
+    }
+    return result;
   }
 
   /**
-   * Releases the given array back to the array pool.
+   * Used by `_.trim` and `_.trimLeft` to get the index of the first non-whitespace
+   * character of `string`.
    *
    * @private
-   * @param {Array} [array] The array to release.
+   * @param {string} string The string to inspect.
+   * @returns {number} Returns the index of the first non-whitespace character.
    */
-  function releaseArray(array) {
-    array.length = 0;
-    if (arrayPool.length < maxPoolSize) {
-      arrayPool.push(array);
-    }
+  function trimmedLeftIndex(string) {
+    var index = -1,
+        length = string.length;
+
+    while (++index < length && isSpace(string.charCodeAt(index))) {}
+    return index;
   }
 
   /**
-   * Releases the given object back to the object pool.
+   * Used by `_.trim` and `_.trimRight` to get the index of the last non-whitespace
+   * character of `string`.
    *
    * @private
-   * @param {Object} [object] The object to release.
+   * @param {string} string The string to inspect.
+   * @returns {number} Returns the index of the last non-whitespace character.
    */
-  function releaseObject(object) {
-    var cache = object.cache;
-    if (cache) {
-      releaseObject(cache);
-    }
-    object.array = object.cache = object.criteria = object.object = object.number = object.string = object.value = null;
-    if (objectPool.length < maxPoolSize) {
-      objectPool.push(object);
-    }
+  function trimmedRightIndex(string) {
+    var index = string.length;
+
+    while (index-- && isSpace(string.charCodeAt(index))) {}
+    return index;
   }
 
   /**
-   * Slices the `collection` from the `start` index up to, but not including,
-   * the `end` index.
-   *
-   * Note: This function is used instead of `Array#slice` to support node lists
-   * in IE < 9 and to ensure dense arrays are returned.
+   * Used by `_.unescape` to convert HTML entities to characters.
    *
    * @private
-   * @param {Array|Object|string} collection The collection to slice.
-   * @param {number} start The start index.
-   * @param {number} end The end index.
-   * @returns {Array} Returns the new array.
+   * @param {string} chr The matched character to unescape.
+   * @returns {string} Returns the unescaped character.
    */
-  function slice(array, start, end) {
-    start || (start = 0);
-    if (typeof end == 'undefined') {
-      end = array ? array.length : 0;
-    }
-    var index = -1,
-        length = end - start || 0,
-        result = Array(length < 0 ? 0 : length);
-
-    while (++index < length) {
-      result[index] = array[start + index];
-    }
-    return result;
+  function unescapeHtmlChar(chr) {
+    return htmlUnescapes[chr];
   }
 
   /*--------------------------------------------------------------------------*/
 
   /**
-   * Create a new `lodash` function using the given context object.
+   * Create a new pristine `lodash` function using the given `context` object.
    *
    * @static
    * @memberOf _
-   * @category Utilities
+   * @category Utility
    * @param {Object} [context=root] The context object.
-   * @returns {Function} Returns the `lodash` function.
+   * @returns {Function} Returns a new `lodash` function.
+   * @example
+   *
+   * _.mixin({ 'foo': _.constant('foo') });
+   *
+   * var lodash = _.runInContext();
+   * lodash.mixin({ 'bar': lodash.constant('bar') });
+   *
+   * _.isFunction(_.foo);
+   * // => true
+   * _.isFunction(_.bar);
+   * // => false
+   *
+   * lodash.isFunction(lodash.foo);
+   * // => false
+   * lodash.isFunction(lodash.bar);
+   * // => true
+   *
+   * // using `context` to mock `Date#getTime` use in `_.now`
+   * var mock = _.runInContext({
+   *   'Date': function() {
+   *     return { 'getTime': getTimeMock };
+   *   }
+   * });
+   *
+   * // or creating a suped-up `defer` in Node.js
+   * var defer = _.runInContext({ 'setTimeout': setImmediate }).defer;
    */
   function runInContext(context) {
     // Avoid issues with some ES3 environments that attempt to use values, named
     // after built-in constructors like `Object`, for the creation of literals.
     // ES5 clears this up by stating that literals must use built-in constructors.
-    // See http://es5.github.io/#x11.1.5.
+    // See https://es5.github.io/#x11.1.5 for more details.
     context = context ? _.defaults(root.Object(), context, _.pick(root, contextProps)) : root;
 
-    /** Native constructor references */
+    /** Native constructor references. */
     var Array = context.Array,
-        Boolean = context.Boolean,
         Date = context.Date,
+        Error = context.Error,
         Function = context.Function,
         Math = context.Math,
         Number = context.Number,
@@ -448,134 +714,171 @@
         String = context.String,
         TypeError = context.TypeError;
 
-    /**
-     * Used for `Array` method references.
-     *
-     * Normally `Array.prototype` would suffice, however, using an array literal
-     * avoids issues in Narwhal.
-     */
-    var arrayRef = [];
-
-    /** Used for native method references */
-    var objectProto = Object.prototype;
-
-    /** Used to restore the original `_` reference in `noConflict` */
-    var oldDash = context._;
-
-    /** Used to resolve the internal [[Class]] of values */
-    var toString = objectProto.toString;
-
-    /** Used to detect if a method is native */
-    var reNative = RegExp('^' +
-      String(toString)
-        .replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
-        .replace(/toString| for [^\]]+/g, '.*?') + '$'
+    /** Used for native method references. */
+    var arrayProto = Array.prototype,
+        objectProto = Object.prototype,
+        stringProto = String.prototype;
+
+    /** Used to resolve the decompiled source of functions. */
+    var fnToString = Function.prototype.toString;
+
+    /** Used to check objects for own properties. */
+    var hasOwnProperty = objectProto.hasOwnProperty;
+
+    /** Used to generate unique IDs. */
+    var idCounter = 0;
+
+    /**
+     * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
+     * of values.
+     */
+    var objToString = objectProto.toString;
+
+    /** Used to restore the original `_` reference in `_.noConflict`. */
+    var oldDash = root._;
+
+    /** Used to detect if a method is native. */
+    var reIsNative = RegExp('^' +
+      fnToString.call(hasOwnProperty).replace(/[\\^$.*+?()[\]{}|]/g, '\\$&')
+      .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
     );
 
-    /** Native method shortcuts */
-    var ceil = Math.ceil,
+    /** Native method references. */
+    var ArrayBuffer = context.ArrayBuffer,
         clearTimeout = context.clearTimeout,
-        floor = Math.floor,
-        fnToString = Function.prototype.toString,
-        getPrototypeOf = isNative(getPrototypeOf = Object.getPrototypeOf) && getPrototypeOf,
-        hasOwnProperty = objectProto.hasOwnProperty,
-        push = arrayRef.push,
+        parseFloat = context.parseFloat,
+        pow = Math.pow,
+        propertyIsEnumerable = objectProto.propertyIsEnumerable,
+        Set = getNative(context, 'Set'),
         setTimeout = context.setTimeout,
-        splice = arrayRef.splice,
-        unshift = arrayRef.unshift;
-
-    /** Used to set meta data on functions */
-    var defineProperty = (function() {
-      // IE 8 only accepts DOM elements
-      try {
-        var o = {},
-            func = isNative(func = Object.defineProperty) && func,
-            result = func(o, o, o) && func;
-      } catch(e) { }
-      return result;
-    }());
-
-    /* Native method shortcuts for methods with the same name as other `lodash` methods */
-    var nativeCreate = isNative(nativeCreate = Object.create) && nativeCreate,
-        nativeIsArray = isNative(nativeIsArray = Array.isArray) && nativeIsArray,
+        splice = arrayProto.splice,
+        Uint8Array = context.Uint8Array,
+        WeakMap = getNative(context, 'WeakMap');
+
+    /* Native method references for those with the same name as other `lodash` methods. */
+    var nativeCeil = Math.ceil,
+        nativeCreate = getNative(Object, 'create'),
+        nativeFloor = Math.floor,
+        nativeIsArray = getNative(Array, 'isArray'),
         nativeIsFinite = context.isFinite,
-        nativeIsNaN = context.isNaN,
-        nativeKeys = isNative(nativeKeys = Object.keys) && nativeKeys,
+        nativeKeys = getNative(Object, 'keys'),
         nativeMax = Math.max,
         nativeMin = Math.min,
+        nativeNow = getNative(Date, 'now'),
         nativeParseInt = context.parseInt,
         nativeRandom = Math.random;
 
-    /** Used to lookup a built-in constructor by [[Class]] */
-    var ctorByClass = {};
-    ctorByClass[arrayClass] = Array;
-    ctorByClass[boolClass] = Boolean;
-    ctorByClass[dateClass] = Date;
-    ctorByClass[funcClass] = Function;
-    ctorByClass[objectClass] = Object;
-    ctorByClass[numberClass] = Number;
-    ctorByClass[regexpClass] = RegExp;
-    ctorByClass[stringClass] = String;
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates a `lodash` object which wraps the given value to enable intuitive
-     * method chaining.
-     *
-     * In addition to Lo-Dash methods, wrappers also have the following `Array` methods:
-     * `concat`, `join`, `pop`, `push`, `reverse`, `shift`, `slice`, `sort`, `splice`,
-     * and `unshift`
-     *
-     * Chaining is supported in custom builds as long as the `value` method is
-     * implicitly or explicitly included in the build.
-     *
-     * The chainable wrapper functions are:
-     * `after`, `assign`, `bind`, `bindAll`, `bindKey`, `chain`, `compact`,
-     * `compose`, `concat`, `countBy`, `create`, `createCallback`, `curry`,
-     * `debounce`, `defaults`, `defer`, `delay`, `difference`, `filter`, `flatten`,
+    /** Used as references for `-Infinity` and `Infinity`. */
+    var NEGATIVE_INFINITY = Number.NEGATIVE_INFINITY,
+        POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
+
+    /** Used as references for the maximum length and index of an array. */
+    var MAX_ARRAY_LENGTH = 4294967295,
+        MAX_ARRAY_INDEX = MAX_ARRAY_LENGTH - 1,
+        HALF_MAX_ARRAY_LENGTH = MAX_ARRAY_LENGTH >>> 1;
+
+    /**
+     * Used as the [maximum length](http://ecma-international.org/ecma-262/6.0/#sec-number.max_safe_integer)
+     * of an array-like value.
+     */
+    var MAX_SAFE_INTEGER = 9007199254740991;
+
+    /** Used to store function metadata. */
+    var metaMap = WeakMap && new WeakMap;
+
+    /** Used to lookup unminified function names. */
+    var realNames = {};
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a `lodash` object which wraps `value` to enable implicit chaining.
+     * Methods that operate on and return arrays, collections, and functions can
+     * be chained together. Methods that retrieve a single value or may return a
+     * primitive value will automatically end the chain returning the unwrapped
+     * value. Explicit chaining may be enabled using `_.chain`. The execution of
+     * chained methods is lazy, that is, execution is deferred until `_#value`
+     * is implicitly or explicitly called.
+     *
+     * Lazy evaluation allows several methods to support shortcut fusion. Shortcut
+     * fusion is an optimization strategy which merge iteratee calls; this can help
+     * to avoid the creation of intermediate data structures and greatly reduce the
+     * number of iteratee executions.
+     *
+     * Chaining is supported in custom builds as long as the `_#value` method is
+     * directly or indirectly included in the build.
+     *
+     * In addition to lodash methods, wrappers have `Array` and `String` methods.
+     *
+     * The wrapper `Array` methods are:
+     * `concat`, `join`, `pop`, `push`, `reverse`, `shift`, `slice`, `sort`,
+     * `splice`, and `unshift`
+     *
+     * The wrapper `String` methods are:
+     * `replace` and `split`
+     *
+     * The wrapper methods that support shortcut fusion are:
+     * `compact`, `drop`, `dropRight`, `dropRightWhile`, `dropWhile`, `filter`,
+     * `first`, `initial`, `last`, `map`, `pluck`, `reject`, `rest`, `reverse`,
+     * `slice`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, `toArray`,
+     * and `where`
+     *
+     * The chainable wrapper methods are:
+     * `after`, `ary`, `assign`, `at`, `before`, `bind`, `bindAll`, `bindKey`,
+     * `callback`, `chain`, `chunk`, `commit`, `compact`, `concat`, `constant`,
+     * `countBy`, `create`, `curry`, `debounce`, `defaults`, `defaultsDeep`,
+     * `defer`, `delay`, `difference`, `drop`, `dropRight`, `dropRightWhile`,
+     * `dropWhile`, `fill`, `filter`, `flatten`, `flattenDeep`, `flow`, `flowRight`,
      * `forEach`, `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`,
      * `functions`, `groupBy`, `indexBy`, `initial`, `intersection`, `invert`,
-     * `invoke`, `keys`, `map`, `max`, `memoize`, `merge`, `min`, `object`, `omit`,
-     * `once`, `pairs`, `partial`, `partialRight`, `pick`, `pluck`, `pull`, `push`,
-     * `range`, `reject`, `remove`, `rest`, `reverse`, `shuffle`, `slice`, `sort`,
-     * `sortBy`, `splice`, `tap`, `throttle`, `times`, `toArray`, `transform`,
-     * `union`, `uniq`, `unshift`, `unzip`, `values`, `where`, `without`, `wrap`,
-     * and `zip`
-     *
-     * The non-chainable wrapper functions are:
-     * `clone`, `cloneDeep`, `contains`, `escape`, `every`, `find`, `findIndex`,
-     * `findKey`, `findLast`, `findLastIndex`, `findLastKey`, `has`, `identity`,
-     * `indexOf`, `isArguments`, `isArray`, `isBoolean`, `isDate`, `isElement`,
-     * `isEmpty`, `isEqual`, `isFinite`, `isFunction`, `isNaN`, `isNull`, `isNumber`,
-     * `isObject`, `isPlainObject`, `isRegExp`, `isString`, `isUndefined`, `join`,
-     * `lastIndexOf`, `mixin`, `noConflict`, `parseInt`, `pop`, `random`, `reduce`,
-     * `reduceRight`, `result`, `shift`, `size`, `some`, `sortedIndex`, `runInContext`,
-     * `template`, `unescape`, `uniqueId`, and `value`
-     *
-     * The wrapper functions `first` and `last` return wrapped values when `n` is
-     * provided, otherwise they return unwrapped values.
-     *
-     * Explicit chaining can be enabled by using the `_.chain` method.
+     * `invoke`, `keys`, `keysIn`, `map`, `mapKeys`, `mapValues`, `matches`,
+     * `matchesProperty`, `memoize`, `merge`, `method`, `methodOf`, `mixin`,
+     * `modArgs`, `negate`, `omit`, `once`, `pairs`, `partial`, `partialRight`,
+     * `partition`, `pick`, `plant`, `pluck`, `property`, `propertyOf`, `pull`,
+     * `pullAt`, `push`, `range`, `rearg`, `reject`, `remove`, `rest`, `restParam`,
+     * `reverse`, `set`, `shuffle`, `slice`, `sort`, `sortBy`, `sortByAll`,
+     * `sortByOrder`, `splice`, `spread`, `take`, `takeRight`, `takeRightWhile`,
+     * `takeWhile`, `tap`, `throttle`, `thru`, `times`, `toArray`, `toPlainObject`,
+     * `transform`, `union`, `uniq`, `unshift`, `unzip`, `unzipWith`, `values`,
+     * `valuesIn`, `where`, `without`, `wrap`, `xor`, `zip`, `zipObject`, `zipWith`
+     *
+     * The wrapper methods that are **not** chainable by default are:
+     * `add`, `attempt`, `camelCase`, `capitalize`, `ceil`, `clone`, `cloneDeep`,
+     * `deburr`, `endsWith`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`,
+     * `findKey`, `findLast`, `findLastIndex`, `findLastKey`, `findWhere`, `first`,
+     * `floor`, `get`, `gt`, `gte`, `has`, `identity`, `includes`, `indexOf`,
+     * `inRange`, `isArguments`, `isArray`, `isBoolean`, `isDate`, `isElement`,
+     * `isEmpty`, `isEqual`, `isError`, `isFinite` `isFunction`, `isMatch`,
+     * `isNative`, `isNaN`, `isNull`, `isNumber`, `isObject`, `isPlainObject`,
+     * `isRegExp`, `isString`, `isUndefined`, `isTypedArray`, `join`, `kebabCase`,
+     * `last`, `lastIndexOf`, `lt`, `lte`, `max`, `min`, `noConflict`, `noop`,
+     * `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`, `random`, `reduce`,
+     * `reduceRight`, `repeat`, `result`, `round`, `runInContext`, `shift`, `size`,
+     * `snakeCase`, `some`, `sortedIndex`, `sortedLastIndex`, `startCase`,
+     * `startsWith`, `sum`, `template`, `trim`, `trimLeft`, `trimRight`, `trunc`,
+     * `unescape`, `uniqueId`, `value`, and `words`
+     *
+     * The wrapper method `sample` will return a wrapped value when `n` is provided,
+     * otherwise an unwrapped value is returned.
      *
      * @name _
      * @constructor
-     * @category Chaining
+     * @category Chain
      * @param {*} value The value to wrap in a `lodash` instance.
-     * @returns {Object} Returns a `lodash` instance.
+     * @returns {Object} Returns the new `lodash` wrapper instance.
      * @example
      *
      * var wrapped = _([1, 2, 3]);
      *
      * // returns an unwrapped value
-     * wrapped.reduce(function(sum, num) {
-     *   return sum + num;
+     * wrapped.reduce(function(total, n) {
+     *   return total + n;
      * });
      * // => 6
      *
      * // returns a wrapped value
-     * var squares = wrapped.map(function(num) {
-     *   return num * num;
+     * var squares = wrapped.map(function(n) {
+     *   return n * n;
      * });
      *
      * _.isArray(squares);
@@ -585,29 +888,42 @@
      * // => true
      */
     function lodash(value) {
-      // don't wrap if already wrapped, even if wrapped by a different `lodash` constructor
-      return (value && typeof value == 'object' && !isArray(value) && hasOwnProperty.call(value, '__wrapped__'))
-       ? value
-       : new lodashWrapper(value);
-    }
-
-    /**
-     * A fast path for creating `lodash` wrapper objects.
-     *
-     * @private
-     * @param {*} value The value to wrap in a `lodash` instance.
-     * @param {boolean} chainAll A flag to enable chaining for all methods
-     * @returns {Object} Returns a `lodash` instance.
-     */
-    function lodashWrapper(value, chainAll) {
+      if (isObjectLike(value) && !isArray(value) && !(value instanceof LazyWrapper)) {
+        if (value instanceof LodashWrapper) {
+          return value;
+        }
+        if (hasOwnProperty.call(value, '__chain__') && hasOwnProperty.call(value, '__wrapped__')) {
+          return wrapperClone(value);
+        }
+      }
+      return new LodashWrapper(value);
+    }
+
+    /**
+     * The function whose prototype all chaining wrappers inherit from.
+     *
+     * @private
+     */
+    function baseLodash() {
+      // No operation performed.
+    }
+
+    /**
+     * The base constructor for creating `lodash` wrapper objects.
+     *
+     * @private
+     * @param {*} value The value to wrap.
+     * @param {boolean} [chainAll] Enable chaining for all wrapper methods.
+     * @param {Array} [actions=[]] Actions to peform to resolve the unwrapped value.
+     */
+    function LodashWrapper(value, chainAll, actions) {
+      this.__wrapped__ = value;
+      this.__actions__ = actions || [];
       this.__chain__ = !!chainAll;
-      this.__wrapped__ = value;
-    }
-    // ensure `new lodashWrapper` is an instance of `lodash`
-    lodashWrapper.prototype = lodash.prototype;
-
-    /**
-     * An object used to flag environments features.
+    }
+
+    /**
+     * An object environment feature flags.
      *
      * @static
      * @memberOf _
@@ -616,26 +932,9 @@
     var support = lodash.support = {};
 
     /**
-     * Detect if functions can be decompiled by `Function#toString`
-     * (all but PS3 and older Opera mobile browsers & avoided in Windows 8 apps).
-     *
-     * @memberOf _.support
-     * @type boolean
-     */
-    support.funcDecomp = !isNative(context.WinRTError) && reThis.test(runInContext);
-
-    /**
-     * Detect if `Function#name` is supported (all but IE).
-     *
-     * @memberOf _.support
-     * @type boolean
-     */
-    support.funcNames = typeof Function.name == 'string';
-
-    /**
-     * By default, the template delimiters used by Lo-Dash are similar to those in
-     * embedded Ruby (ERB). Change the following template settings to use alternative
-     * delimiters.
+     * By default, the template delimiters used by lodash are like those in
+     * embedded Ruby (ERB). Change the following template settings to use
+     * alternative delimiters.
      *
      * @static
      * @memberOf _
@@ -649,7 +948,7 @@
        * @memberOf _.templateSettings
        * @type RegExp
        */
-      'escape': /<%-([\s\S]+?)%>/g,
+      'escape': reEscape,
 
       /**
        * Used to detect code to be evaluated.
@@ -657,7 +956,7 @@
        * @memberOf _.templateSettings
        * @type RegExp
        */
-      'evaluate': /<%([\s\S]+?)%>/g,
+      'evaluate': reEvaluate,
 
       /**
        * Used to detect `data` property values to inject.
@@ -693,134 +992,747 @@
       }
     };
 
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * The base implementation of `_.bind` that creates the bound function and
-     * sets its meta data.
-     *
-     * @private
-     * @param {Array} bindData The bind data array.
-     * @returns {Function} Returns the new bound function.
-     */
-    function baseBind(bindData) {
-      var func = bindData[0],
-          partialArgs = bindData[2],
-          thisArg = bindData[4];
-
-      function bound() {
-        // `Function#bind` spec
-        // http://es5.github.io/#x15.3.4.5
-        if (partialArgs) {
-          // avoid `arguments` object deoptimizations by using `slice` instead
-          // of `Array.prototype.slice.call` and not assigning `arguments` to a
-          // variable as a ternary expression
-          var args = slice(partialArgs);
-          push.apply(args, arguments);
-        }
-        // mimic the constructor's `return` behavior
-        // http://es5.github.io/#x13.2.2
-        if (this instanceof bound) {
-          // ensure `new bound` is an instance of `func`
-          var thisBinding = baseCreate(func.prototype),
-              result = func.apply(thisBinding, args || arguments);
-          return isObject(result) ? result : thisBinding;
-        }
-        return func.apply(thisArg, args || arguments);
-      }
-      setBindData(bound, bindData);
-      return bound;
-    }
-
-    /**
-     * The base implementation of `_.clone` without argument juggling or support
-     * for `thisArg` binding.
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a lazy wrapper object which wraps `value` to enable lazy evaluation.
+     *
+     * @private
+     * @param {*} value The value to wrap.
+     */
+    function LazyWrapper(value) {
+      this.__wrapped__ = value;
+      this.__actions__ = [];
+      this.__dir__ = 1;
+      this.__filtered__ = false;
+      this.__iteratees__ = [];
+      this.__takeCount__ = POSITIVE_INFINITY;
+      this.__views__ = [];
+    }
+
+    /**
+     * Creates a clone of the lazy wrapper object.
+     *
+     * @private
+     * @name clone
+     * @memberOf LazyWrapper
+     * @returns {Object} Returns the cloned `LazyWrapper` object.
+     */
+    function lazyClone() {
+      var result = new LazyWrapper(this.__wrapped__);
+      result.__actions__ = arrayCopy(this.__actions__);
+      result.__dir__ = this.__dir__;
+      result.__filtered__ = this.__filtered__;
+      result.__iteratees__ = arrayCopy(this.__iteratees__);
+      result.__takeCount__ = this.__takeCount__;
+      result.__views__ = arrayCopy(this.__views__);
+      return result;
+    }
+
+    /**
+     * Reverses the direction of lazy iteration.
+     *
+     * @private
+     * @name reverse
+     * @memberOf LazyWrapper
+     * @returns {Object} Returns the new reversed `LazyWrapper` object.
+     */
+    function lazyReverse() {
+      if (this.__filtered__) {
+        var result = new LazyWrapper(this);
+        result.__dir__ = -1;
+        result.__filtered__ = true;
+      } else {
+        result = this.clone();
+        result.__dir__ *= -1;
+      }
+      return result;
+    }
+
+    /**
+     * Extracts the unwrapped value from its lazy wrapper.
+     *
+     * @private
+     * @name value
+     * @memberOf LazyWrapper
+     * @returns {*} Returns the unwrapped value.
+     */
+    function lazyValue() {
+      var array = this.__wrapped__.value(),
+          dir = this.__dir__,
+          isArr = isArray(array),
+          isRight = dir < 0,
+          arrLength = isArr ? array.length : 0,
+          view = getView(0, arrLength, this.__views__),
+          start = view.start,
+          end = view.end,
+          length = end - start,
+          index = isRight ? end : (start - 1),
+          iteratees = this.__iteratees__,
+          iterLength = iteratees.length,
+          resIndex = 0,
+          takeCount = nativeMin(length, this.__takeCount__);
+
+      if (!isArr || arrLength < LARGE_ARRAY_SIZE || (arrLength == length && takeCount == length)) {
+        return baseWrapperValue(array, this.__actions__);
+      }
+      var result = [];
+
+      outer:
+      while (length-- && resIndex < takeCount) {
+        index += dir;
+
+        var iterIndex = -1,
+            value = array[index];
+
+        while (++iterIndex < iterLength) {
+          var data = iteratees[iterIndex],
+              iteratee = data.iteratee,
+              type = data.type,
+              computed = iteratee(value);
+
+          if (type == LAZY_MAP_FLAG) {
+            value = computed;
+          } else if (!computed) {
+            if (type == LAZY_FILTER_FLAG) {
+              continue outer;
+            } else {
+              break outer;
+            }
+          }
+        }
+        result[resIndex++] = value;
+      }
+      return result;
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a cache object to store key/value pairs.
+     *
+     * @private
+     * @static
+     * @name Cache
+     * @memberOf _.memoize
+     */
+    function MapCache() {
+      this.__data__ = {};
+    }
+
+    /**
+     * Removes `key` and its value from the cache.
+     *
+     * @private
+     * @name delete
+     * @memberOf _.memoize.Cache
+     * @param {string} key The key of the value to remove.
+     * @returns {boolean} Returns `true` if the entry was removed successfully, else `false`.
+     */
+    function mapDelete(key) {
+      return this.has(key) && delete this.__data__[key];
+    }
+
+    /**
+     * Gets the cached value for `key`.
+     *
+     * @private
+     * @name get
+     * @memberOf _.memoize.Cache
+     * @param {string} key The key of the value to get.
+     * @returns {*} Returns the cached value.
+     */
+    function mapGet(key) {
+      return key == '__proto__' ? undefined : this.__data__[key];
+    }
+
+    /**
+     * Checks if a cached value for `key` exists.
+     *
+     * @private
+     * @name has
+     * @memberOf _.memoize.Cache
+     * @param {string} key The key of the entry to check.
+     * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
+     */
+    function mapHas(key) {
+      return key != '__proto__' && hasOwnProperty.call(this.__data__, key);
+    }
+
+    /**
+     * Sets `value` to `key` of the cache.
+     *
+     * @private
+     * @name set
+     * @memberOf _.memoize.Cache
+     * @param {string} key The key of the value to cache.
+     * @param {*} value The value to cache.
+     * @returns {Object} Returns the cache object.
+     */
+    function mapSet(key, value) {
+      if (key != '__proto__') {
+        this.__data__[key] = value;
+      }
+      return this;
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     *
+     * Creates a cache object to store unique values.
+     *
+     * @private
+     * @param {Array} [values] The values to cache.
+     */
+    function SetCache(values) {
+      var length = values ? values.length : 0;
+
+      this.data = { 'hash': nativeCreate(null), 'set': new Set };
+      while (length--) {
+        this.push(values[length]);
+      }
+    }
+
+    /**
+     * Checks if `value` is in `cache` mimicking the return signature of
+     * `_.indexOf` by returning `0` if the value is found, else `-1`.
+     *
+     * @private
+     * @param {Object} cache The cache to search.
+     * @param {*} value The value to search for.
+     * @returns {number} Returns `0` if `value` is found, else `-1`.
+     */
+    function cacheIndexOf(cache, value) {
+      var data = cache.data,
+          result = (typeof value == 'string' || isObject(value)) ? data.set.has(value) : data.hash[value];
+
+      return result ? 0 : -1;
+    }
+
+    /**
+     * Adds `value` to the cache.
+     *
+     * @private
+     * @name push
+     * @memberOf SetCache
+     * @param {*} value The value to cache.
+     */
+    function cachePush(value) {
+      var data = this.data;
+      if (typeof value == 'string' || isObject(value)) {
+        data.set.add(value);
+      } else {
+        data.hash[value] = true;
+      }
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a new array joining `array` with `other`.
+     *
+     * @private
+     * @param {Array} array The array to join.
+     * @param {Array} other The other array to join.
+     * @returns {Array} Returns the new concatenated array.
+     */
+    function arrayConcat(array, other) {
+      var index = -1,
+          length = array.length,
+          othIndex = -1,
+          othLength = other.length,
+          result = Array(length + othLength);
+
+      while (++index < length) {
+        result[index] = array[index];
+      }
+      while (++othIndex < othLength) {
+        result[index++] = other[othIndex];
+      }
+      return result;
+    }
+
+    /**
+     * Copies the values of `source` to `array`.
+     *
+     * @private
+     * @param {Array} source The array to copy values from.
+     * @param {Array} [array=[]] The array to copy values to.
+     * @returns {Array} Returns `array`.
+     */
+    function arrayCopy(source, array) {
+      var index = -1,
+          length = source.length;
+
+      array || (array = Array(length));
+      while (++index < length) {
+        array[index] = source[index];
+      }
+      return array;
+    }
+
+    /**
+     * A specialized version of `_.forEach` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array} Returns `array`.
+     */
+    function arrayEach(array, iteratee) {
+      var index = -1,
+          length = array.length;
+
+      while (++index < length) {
+        if (iteratee(array[index], index, array) === false) {
+          break;
+        }
+      }
+      return array;
+    }
+
+    /**
+     * A specialized version of `_.forEachRight` for arrays without support for
+     * callback shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array} Returns `array`.
+     */
+    function arrayEachRight(array, iteratee) {
+      var length = array.length;
+
+      while (length--) {
+        if (iteratee(array[length], length, array) === false) {
+          break;
+        }
+      }
+      return array;
+    }
+
+    /**
+     * A specialized version of `_.every` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {boolean} Returns `true` if all elements pass the predicate check,
+     *  else `false`.
+     */
+    function arrayEvery(array, predicate) {
+      var index = -1,
+          length = array.length;
+
+      while (++index < length) {
+        if (!predicate(array[index], index, array)) {
+          return false;
+        }
+      }
+      return true;
+    }
+
+    /**
+     * A specialized version of `baseExtremum` for arrays which invokes `iteratee`
+     * with one argument: (value).
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {Function} comparator The function used to compare values.
+     * @param {*} exValue The initial extremum value.
+     * @returns {*} Returns the extremum value.
+     */
+    function arrayExtremum(array, iteratee, comparator, exValue) {
+      var index = -1,
+          length = array.length,
+          computed = exValue,
+          result = computed;
+
+      while (++index < length) {
+        var value = array[index],
+            current = +iteratee(value);
+
+        if (comparator(current, computed)) {
+          computed = current;
+          result = value;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * A specialized version of `_.filter` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {Array} Returns the new filtered array.
+     */
+    function arrayFilter(array, predicate) {
+      var index = -1,
+          length = array.length,
+          resIndex = -1,
+          result = [];
+
+      while (++index < length) {
+        var value = array[index];
+        if (predicate(value, index, array)) {
+          result[++resIndex] = value;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * A specialized version of `_.map` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array} Returns the new mapped array.
+     */
+    function arrayMap(array, iteratee) {
+      var index = -1,
+          length = array.length,
+          result = Array(length);
+
+      while (++index < length) {
+        result[index] = iteratee(array[index], index, array);
+      }
+      return result;
+    }
+
+    /**
+     * Appends the elements of `values` to `array`.
+     *
+     * @private
+     * @param {Array} array The array to modify.
+     * @param {Array} values The values to append.
+     * @returns {Array} Returns `array`.
+     */
+    function arrayPush(array, values) {
+      var index = -1,
+          length = values.length,
+          offset = array.length;
+
+      while (++index < length) {
+        array[offset + index] = values[index];
+      }
+      return array;
+    }
+
+    /**
+     * A specialized version of `_.reduce` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {*} [accumulator] The initial value.
+     * @param {boolean} [initFromArray] Specify using the first element of `array`
+     *  as the initial value.
+     * @returns {*} Returns the accumulated value.
+     */
+    function arrayReduce(array, iteratee, accumulator, initFromArray) {
+      var index = -1,
+          length = array.length;
+
+      if (initFromArray && length) {
+        accumulator = array[++index];
+      }
+      while (++index < length) {
+        accumulator = iteratee(accumulator, array[index], index, array);
+      }
+      return accumulator;
+    }
+
+    /**
+     * A specialized version of `_.reduceRight` for arrays without support for
+     * callback shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {*} [accumulator] The initial value.
+     * @param {boolean} [initFromArray] Specify using the last element of `array`
+     *  as the initial value.
+     * @returns {*} Returns the accumulated value.
+     */
+    function arrayReduceRight(array, iteratee, accumulator, initFromArray) {
+      var length = array.length;
+      if (initFromArray && length) {
+        accumulator = array[--length];
+      }
+      while (length--) {
+        accumulator = iteratee(accumulator, array[length], length, array);
+      }
+      return accumulator;
+    }
+
+    /**
+     * A specialized version of `_.some` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {boolean} Returns `true` if any element passes the predicate check,
+     *  else `false`.
+     */
+    function arraySome(array, predicate) {
+      var index = -1,
+          length = array.length;
+
+      while (++index < length) {
+        if (predicate(array[index], index, array)) {
+          return true;
+        }
+      }
+      return false;
+    }
+
+    /**
+     * A specialized version of `_.sum` for arrays without support for callback
+     * shorthands and `this` binding..
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {number} Returns the sum.
+     */
+    function arraySum(array, iteratee) {
+      var length = array.length,
+          result = 0;
+
+      while (length--) {
+        result += +iteratee(array[length]) || 0;
+      }
+      return result;
+    }
+
+    /**
+     * Used by `_.defaults` to customize its `_.assign` use.
+     *
+     * @private
+     * @param {*} objectValue The destination object property value.
+     * @param {*} sourceValue The source object property value.
+     * @returns {*} Returns the value to assign to the destination object.
+     */
+    function assignDefaults(objectValue, sourceValue) {
+      return objectValue === undefined ? sourceValue : objectValue;
+    }
+
+    /**
+     * Used by `_.template` to customize its `_.assign` use.
+     *
+     * **Note:** This function is like `assignDefaults` except that it ignores
+     * inherited property values when checking if a property is `undefined`.
+     *
+     * @private
+     * @param {*} objectValue The destination object property value.
+     * @param {*} sourceValue The source object property value.
+     * @param {string} key The key associated with the object and source values.
+     * @param {Object} object The destination object.
+     * @returns {*} Returns the value to assign to the destination object.
+     */
+    function assignOwnDefaults(objectValue, sourceValue, key, object) {
+      return (objectValue === undefined || !hasOwnProperty.call(object, key))
+        ? sourceValue
+        : objectValue;
+    }
+
+    /**
+     * A specialized version of `_.assign` for customizing assigned values without
+     * support for argument juggling, multiple sources, and `this` binding `customizer`
+     * functions.
+     *
+     * @private
+     * @param {Object} object The destination object.
+     * @param {Object} source The source object.
+     * @param {Function} customizer The function to customize assigned values.
+     * @returns {Object} Returns `object`.
+     */
+    function assignWith(object, source, customizer) {
+      var index = -1,
+          props = keys(source),
+          length = props.length;
+
+      while (++index < length) {
+        var key = props[index],
+            value = object[key],
+            result = customizer(value, source[key], key, object, source);
+
+        if ((result === result ? (result !== value) : (value === value)) ||
+            (value === undefined && !(key in object))) {
+          object[key] = result;
+        }
+      }
+      return object;
+    }
+
+    /**
+     * The base implementation of `_.assign` without support for argument juggling,
+     * multiple sources, and `customizer` functions.
+     *
+     * @private
+     * @param {Object} object The destination object.
+     * @param {Object} source The source object.
+     * @returns {Object} Returns `object`.
+     */
+    function baseAssign(object, source) {
+      return source == null
+        ? object
+        : baseCopy(source, keys(source), object);
+    }
+
+    /**
+     * The base implementation of `_.at` without support for string collections
+     * and individual key arguments.
+     *
+     * @private
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {number[]|string[]} props The property names or indexes of elements to pick.
+     * @returns {Array} Returns the new array of picked elements.
+     */
+    function baseAt(collection, props) {
+      var index = -1,
+          isNil = collection == null,
+          isArr = !isNil && isArrayLike(collection),
+          length = isArr ? collection.length : 0,
+          propsLength = props.length,
+          result = Array(propsLength);
+
+      while(++index < propsLength) {
+        var key = props[index];
+        if (isArr) {
+          result[index] = isIndex(key, length) ? collection[key] : undefined;
+        } else {
+          result[index] = isNil ? undefined : collection[key];
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Copies properties of `source` to `object`.
+     *
+     * @private
+     * @param {Object} source The object to copy properties from.
+     * @param {Array} props The property names to copy.
+     * @param {Object} [object={}] The object to copy properties to.
+     * @returns {Object} Returns `object`.
+     */
+    function baseCopy(source, props, object) {
+      object || (object = {});
+
+      var index = -1,
+          length = props.length;
+
+      while (++index < length) {
+        var key = props[index];
+        object[key] = source[key];
+      }
+      return object;
+    }
+
+    /**
+     * The base implementation of `_.callback` which supports specifying the
+     * number of arguments to provide to `func`.
+     *
+     * @private
+     * @param {*} [func=_.identity] The value to convert to a callback.
+     * @param {*} [thisArg] The `this` binding of `func`.
+     * @param {number} [argCount] The number of arguments to provide to `func`.
+     * @returns {Function} Returns the callback.
+     */
+    function baseCallback(func, thisArg, argCount) {
+      var type = typeof func;
+      if (type == 'function') {
+        return thisArg === undefined
+          ? func
+          : bindCallback(func, thisArg, argCount);
+      }
+      if (func == null) {
+        return identity;
+      }
+      if (type == 'object') {
+        return baseMatches(func);
+      }
+      return thisArg === undefined
+        ? property(func)
+        : baseMatchesProperty(func, thisArg);
+    }
+
+    /**
+     * The base implementation of `_.clone` without support for argument juggling
+     * and `this` binding `customizer` functions.
      *
      * @private
      * @param {*} value The value to clone.
-     * @param {boolean} [isDeep=false] Specify a deep clone.
-     * @param {Function} [callback] The function to customize cloning values.
+     * @param {boolean} [isDeep] Specify a deep clone.
+     * @param {Function} [customizer] The function to customize cloning values.
+     * @param {string} [key] The key of `value`.
+     * @param {Object} [object] The object `value` belongs to.
      * @param {Array} [stackA=[]] Tracks traversed source objects.
      * @param {Array} [stackB=[]] Associates clones with source counterparts.
      * @returns {*} Returns the cloned value.
      */
-    function baseClone(value, isDeep, callback, stackA, stackB) {
-      if (callback) {
-        var result = callback(value);
-        if (typeof result != 'undefined') {
-          return result;
-        }
-      }
-      // inspect [[Class]]
-      var isObj = isObject(value);
-      if (isObj) {
-        var className = toString.call(value);
-        if (!cloneableClasses[className]) {
-          return value;
-        }
-        var ctor = ctorByClass[className];
-        switch (className) {
-          case boolClass:
-          case dateClass:
-            return new ctor(+value);
-
-          case numberClass:
-          case stringClass:
-            return new ctor(value);
-
-          case regexpClass:
-            result = ctor(value.source, reFlags.exec(value));
-            result.lastIndex = value.lastIndex;
-            return result;
-        }
-      } else {
+    function baseClone(value, isDeep, customizer, key, object, stackA, stackB) {
+      var result;
+      if (customizer) {
+        result = object ? customizer(value, key, object) : customizer(value);
+      }
+      if (result !== undefined) {
+        return result;
+      }
+      if (!isObject(value)) {
         return value;
       }
       var isArr = isArray(value);
-      if (isDeep) {
-        // check for circular references and return corresponding clone
-        var initedStack = !stackA;
-        stackA || (stackA = getArray());
-        stackB || (stackB = getArray());
-
-        var length = stackA.length;
-        while (length--) {
-          if (stackA[length] == value) {
-            return stackB[length];
+      if (isArr) {
+        result = initCloneArray(value);
+        if (!isDeep) {
+          return arrayCopy(value, result);
+        }
+      } else {
+        var tag = objToString.call(value),
+            isFunc = tag == funcTag;
+
+        if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
+          result = initCloneObject(isFunc ? {} : value);
+          if (!isDeep) {
+            return baseAssign(result, value);
           }
-        }
-        result = isArr ? ctor(value.length) : {};
-      }
-      else {
-        result = isArr ? slice(value) : assign({}, value);
-      }
-      // add array properties assigned by `RegExp#exec`
-      if (isArr) {
-        if (hasOwnProperty.call(value, 'index')) {
-          result.index = value.index;
-        }
-        if (hasOwnProperty.call(value, 'input')) {
-          result.input = value.input;
-        }
-      }
-      // exit for shallow clone
-      if (!isDeep) {
-        return result;
-      }
-      // add the source value to the stack of traversed objects
-      // and associate it with its clone
+        } else {
+          return cloneableTags[tag]
+            ? initCloneByTag(value, tag, isDeep)
+            : (object ? value : {});
+        }
+      }
+      // Check for circular references and return its corresponding clone.
+      stackA || (stackA = []);
+      stackB || (stackB = []);
+
+      var length = stackA.length;
+      while (length--) {
+        if (stackA[length] == value) {
+          return stackB[length];
+        }
+      }
+      // Add the source value to the stack of traversed objects and associate it with its clone.
       stackA.push(value);
       stackB.push(result);
 
-      // recursively populate clone (susceptible to call stack limits)
-      (isArr ? forEach : forOwn)(value, function(objValue, key) {
-        result[key] = baseClone(objValue, isDeep, callback, stackA, stackB);
+      // Recursively populate clone (susceptible to call stack limits).
+      (isArr ? arrayEach : baseForOwn)(value, function(subValue, key) {
+        result[key] = baseClone(subValue, isDeep, customizer, key, value, stackA, stackB);
       });
-
-      if (initedStack) {
-        releaseArray(stackA);
-        releaseArray(stackB);
-      }
       return result;
     }
 
@@ -832,537 +1744,1248 @@
      * @param {Object} prototype The object to inherit from.
      * @returns {Object} Returns the new object.
      */
-    function baseCreate(prototype, properties) {
-      return isObject(prototype) ? nativeCreate(prototype) : {};
-    }
-    // fallback for browsers without `Object.create`
-    if (!nativeCreate) {
-      baseCreate = (function() {
-        function Object() {}
-        return function(prototype) {
-          if (isObject(prototype)) {
-            Object.prototype = prototype;
-            var result = new Object;
-            Object.prototype = null;
+    var baseCreate = (function() {
+      function object() {}
+      return function(prototype) {
+        if (isObject(prototype)) {
+          object.prototype = prototype;
+          var result = new object;
+          object.prototype = undefined;
+        }
+        return result || {};
+      };
+    }());
+
+    /**
+     * The base implementation of `_.delay` and `_.defer` which accepts an index
+     * of where to slice the arguments to provide to `func`.
+     *
+     * @private
+     * @param {Function} func The function to delay.
+     * @param {number} wait The number of milliseconds to delay invocation.
+     * @param {Object} args The arguments provide to `func`.
+     * @returns {number} Returns the timer id.
+     */
+    function baseDelay(func, wait, args) {
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      return setTimeout(function() { func.apply(undefined, args); }, wait);
+    }
+
+    /**
+     * The base implementation of `_.difference` which accepts a single array
+     * of values to exclude.
+     *
+     * @private
+     * @param {Array} array The array to inspect.
+     * @param {Array} values The values to exclude.
+     * @returns {Array} Returns the new array of filtered values.
+     */
+    function baseDifference(array, values) {
+      var length = array ? array.length : 0,
+          result = [];
+
+      if (!length) {
+        return result;
+      }
+      var index = -1,
+          indexOf = getIndexOf(),
+          isCommon = indexOf === baseIndexOf,
+          cache = (isCommon && values.length >= LARGE_ARRAY_SIZE) ? createCache(values) : null,
+          valuesLength = values.length;
+
+      if (cache) {
+        indexOf = cacheIndexOf;
+        isCommon = false;
+        values = cache;
+      }
+      outer:
+      while (++index < length) {
+        var value = array[index];
+
+        if (isCommon && value === value) {
+          var valuesIndex = valuesLength;
+          while (valuesIndex--) {
+            if (values[valuesIndex] === value) {
+              continue outer;
+            }
+          }
+          result.push(value);
+        }
+        else if (indexOf(values, value, 0) < 0) {
+          result.push(value);
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.forEach` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array|Object|string} Returns `collection`.
+     */
+    var baseEach = createBaseEach(baseForOwn);
+
+    /**
+     * The base implementation of `_.forEachRight` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array|Object|string} Returns `collection`.
+     */
+    var baseEachRight = createBaseEach(baseForOwnRight, true);
+
+    /**
+     * The base implementation of `_.every` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {boolean} Returns `true` if all elements pass the predicate check,
+     *  else `false`
+     */
+    function baseEvery(collection, predicate) {
+      var result = true;
+      baseEach(collection, function(value, index, collection) {
+        result = !!predicate(value, index, collection);
+        return result;
+      });
+      return result;
+    }
+
+    /**
+     * Gets the extremum value of `collection` invoking `iteratee` for each value
+     * in `collection` to generate the criterion by which the value is ranked.
+     * The `iteratee` is invoked with three arguments: (value, index|key, collection).
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {Function} comparator The function used to compare values.
+     * @param {*} exValue The initial extremum value.
+     * @returns {*} Returns the extremum value.
+     */
+    function baseExtremum(collection, iteratee, comparator, exValue) {
+      var computed = exValue,
+          result = computed;
+
+      baseEach(collection, function(value, index, collection) {
+        var current = +iteratee(value, index, collection);
+        if (comparator(current, computed) || (current === exValue && current === result)) {
+          computed = current;
+          result = value;
+        }
+      });
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.fill` without an iteratee call guard.
+     *
+     * @private
+     * @param {Array} array The array to fill.
+     * @param {*} value The value to fill `array` with.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns `array`.
+     */
+    function baseFill(array, value, start, end) {
+      var length = array.length;
+
+      start = start == null ? 0 : (+start || 0);
+      if (start < 0) {
+        start = -start > length ? 0 : (length + start);
+      }
+      end = (end === undefined || end > length) ? length : (+end || 0);
+      if (end < 0) {
+        end += length;
+      }
+      length = start > end ? 0 : (end >>> 0);
+      start >>>= 0;
+
+      while (start < length) {
+        array[start++] = value;
+      }
+      return array;
+    }
+
+    /**
+     * The base implementation of `_.filter` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {Array} Returns the new filtered array.
+     */
+    function baseFilter(collection, predicate) {
+      var result = [];
+      baseEach(collection, function(value, index, collection) {
+        if (predicate(value, index, collection)) {
+          result.push(value);
+        }
+      });
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.find`, `_.findLast`, `_.findKey`, and `_.findLastKey`,
+     * without support for callback shorthands and `this` binding, which iterates
+     * over `collection` using the provided `eachFunc`.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {Function} predicate The function invoked per iteration.
+     * @param {Function} eachFunc The function to iterate over `collection`.
+     * @param {boolean} [retKey] Specify returning the key of the found element
+     *  instead of the element itself.
+     * @returns {*} Returns the found element or its key, else `undefined`.
+     */
+    function baseFind(collection, predicate, eachFunc, retKey) {
+      var result;
+      eachFunc(collection, function(value, key, collection) {
+        if (predicate(value, key, collection)) {
+          result = retKey ? key : value;
+          return false;
+        }
+      });
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.flatten` with added support for restricting
+     * flattening and specifying the start index.
+     *
+     * @private
+     * @param {Array} array The array to flatten.
+     * @param {boolean} [isDeep] Specify a deep flatten.
+     * @param {boolean} [isStrict] Restrict flattening to arrays-like objects.
+     * @param {Array} [result=[]] The initial result value.
+     * @returns {Array} Returns the new flattened array.
+     */
+    function baseFlatten(array, isDeep, isStrict, result) {
+      result || (result = []);
+
+      var index = -1,
+          length = array.length;
+
+      while (++index < length) {
+        var value = array[index];
+        if (isObjectLike(value) && isArrayLike(value) &&
+            (isStrict || isArray(value) || isArguments(value))) {
+          if (isDeep) {
+            // Recursively flatten arrays (susceptible to call stack limits).
+            baseFlatten(value, isDeep, isStrict, result);
+          } else {
+            arrayPush(result, value);
           }
-          return result || context.Object();
+        } else if (!isStrict) {
+          result[result.length] = value;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `baseForIn` and `baseForOwn` which iterates
+     * over `object` properties returned by `keysFunc` invoking `iteratee` for
+     * each property. Iteratee functions may exit iteration early by explicitly
+     * returning `false`.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {Function} keysFunc The function to get the keys of `object`.
+     * @returns {Object} Returns `object`.
+     */
+    var baseFor = createBaseFor();
+
+    /**
+     * This function is like `baseFor` except that it iterates over properties
+     * in the opposite order.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {Function} keysFunc The function to get the keys of `object`.
+     * @returns {Object} Returns `object`.
+     */
+    var baseForRight = createBaseFor(true);
+
+    /**
+     * The base implementation of `_.forIn` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     */
+    function baseForIn(object, iteratee) {
+      return baseFor(object, iteratee, keysIn);
+    }
+
+    /**
+     * The base implementation of `_.forOwn` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     */
+    function baseForOwn(object, iteratee) {
+      return baseFor(object, iteratee, keys);
+    }
+
+    /**
+     * The base implementation of `_.forOwnRight` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     */
+    function baseForOwnRight(object, iteratee) {
+      return baseForRight(object, iteratee, keys);
+    }
+
+    /**
+     * The base implementation of `_.functions` which creates an array of
+     * `object` function property names filtered from those provided.
+     *
+     * @private
+     * @param {Object} object The object to inspect.
+     * @param {Array} props The property names to filter.
+     * @returns {Array} Returns the new array of filtered property names.
+     */
+    function baseFunctions(object, props) {
+      var index = -1,
+          length = props.length,
+          resIndex = -1,
+          result = [];
+
+      while (++index < length) {
+        var key = props[index];
+        if (isFunction(object[key])) {
+          result[++resIndex] = key;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `get` without support for string paths
+     * and default values.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Array} path The path of the property to get.
+     * @param {string} [pathKey] The key representation of path.
+     * @returns {*} Returns the resolved value.
+     */
+    function baseGet(object, path, pathKey) {
+      if (object == null) {
+        return;
+      }
+      if (pathKey !== undefined && pathKey in toObject(object)) {
+        path = [pathKey];
+      }
+      var index = 0,
+          length = path.length;
+
+      while (object != null && index < length) {
+        object = object[path[index++]];
+      }
+      return (index && index == length) ? object : undefined;
+    }
+
+    /**
+     * The base implementation of `_.isEqual` without support for `this` binding
+     * `customizer` functions.
+     *
+     * @private
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @param {Function} [customizer] The function to customize comparing values.
+     * @param {boolean} [isLoose] Specify performing partial comparisons.
+     * @param {Array} [stackA] Tracks traversed `value` objects.
+     * @param {Array} [stackB] Tracks traversed `other` objects.
+     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
+     */
+    function baseIsEqual(value, other, customizer, isLoose, stackA, stackB) {
+      if (value === other) {
+        return true;
+      }
+      if (value == null || other == null || (!isObject(value) && !isObjectLike(other))) {
+        return value !== value && other !== other;
+      }
+      return baseIsEqualDeep(value, other, baseIsEqual, customizer, isLoose, stackA, stackB);
+    }
+
+    /**
+     * A specialized version of `baseIsEqual` for arrays and objects which performs
+     * deep comparisons and tracks traversed objects enabling objects with circular
+     * references to be compared.
+     *
+     * @private
+     * @param {Object} object The object to compare.
+     * @param {Object} other The other object to compare.
+     * @param {Function} equalFunc The function to determine equivalents of values.
+     * @param {Function} [customizer] The function to customize comparing objects.
+     * @param {boolean} [isLoose] Specify performing partial comparisons.
+     * @param {Array} [stackA=[]] Tracks traversed `value` objects.
+     * @param {Array} [stackB=[]] Tracks traversed `other` objects.
+     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
+     */
+    function baseIsEqualDeep(object, other, equalFunc, customizer, isLoose, stackA, stackB) {
+      var objIsArr = isArray(object),
+          othIsArr = isArray(other),
+          objTag = arrayTag,
+          othTag = arrayTag;
+
+      if (!objIsArr) {
+        objTag = objToString.call(object);
+        if (objTag == argsTag) {
+          objTag = objectTag;
+        } else if (objTag != objectTag) {
+          objIsArr = isTypedArray(object);
+        }
+      }
+      if (!othIsArr) {
+        othTag = objToString.call(other);
+        if (othTag == argsTag) {
+          othTag = objectTag;
+        } else if (othTag != objectTag) {
+          othIsArr = isTypedArray(other);
+        }
+      }
+      var objIsObj = objTag == objectTag,
+          othIsObj = othTag == objectTag,
+          isSameTag = objTag == othTag;
+
+      if (isSameTag && !(objIsArr || objIsObj)) {
+        return equalByTag(object, other, objTag);
+      }
+      if (!isLoose) {
+        var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
+            othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');
+
+        if (objIsWrapped || othIsWrapped) {
+          return equalFunc(objIsWrapped ? object.value() : object, othIsWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
+        }
+      }
+      if (!isSameTag) {
+        return false;
+      }
+      // Assume cyclic values are equal.
+      // For more information on detecting circular references see https://es5.github.io/#JO.
+      stackA || (stackA = []);
+      stackB || (stackB = []);
+
+      var length = stackA.length;
+      while (length--) {
+        if (stackA[length] == object) {
+          return stackB[length] == other;
+        }
+      }
+      // Add `object` and `other` to the stack of traversed objects.
+      stackA.push(object);
+      stackB.push(other);
+
+      var result = (objIsArr ? equalArrays : equalObjects)(object, other, equalFunc, customizer, isLoose, stackA, stackB);
+
+      stackA.pop();
+      stackB.pop();
+
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.isMatch` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Object} object The object to inspect.
+     * @param {Array} matchData The propery names, values, and compare flags to match.
+     * @param {Function} [customizer] The function to customize comparing objects.
+     * @returns {boolean} Returns `true` if `object` is a match, else `false`.
+     */
+    function baseIsMatch(object, matchData, customizer) {
+      var index = matchData.length,
+          length = index,
+          noCustomizer = !customizer;
+
+      if (object == null) {
+        return !length;
+      }
+      object = toObject(object);
+      while (index--) {
+        var data = matchData[index];
+        if ((noCustomizer && data[2])
+              ? data[1] !== object[data[0]]
+              : !(data[0] in object)
+            ) {
+          return false;
+        }
+      }
+      while (++index < length) {
+        data = matchData[index];
+        var key = data[0],
+            objValue = object[key],
+            srcValue = data[1];
+
+        if (noCustomizer && data[2]) {
+          if (objValue === undefined && !(key in object)) {
+            return false;
+          }
+        } else {
+          var result = customizer ? customizer(objValue, srcValue, key) : undefined;
+          if (!(result === undefined ? baseIsEqual(srcValue, objValue, customizer, true) : result)) {
+            return false;
+          }
+        }
+      }
+      return true;
+    }
+
+    /**
+     * The base implementation of `_.map` without support for callback shorthands
+     * and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array} Returns the new mapped array.
+     */
+    function baseMap(collection, iteratee) {
+      var index = -1,
+          result = isArrayLike(collection) ? Array(collection.length) : [];
+
+      baseEach(collection, function(value, key, collection) {
+        result[++index] = iteratee(value, key, collection);
+      });
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.matches` which does not clone `source`.
+     *
+     * @private
+     * @param {Object} source The object of property values to match.
+     * @returns {Function} Returns the new function.
+     */
+    function baseMatches(source) {
+      var matchData = getMatchData(source);
+      if (matchData.length == 1 && matchData[0][2]) {
+        var key = matchData[0][0],
+            value = matchData[0][1];
+
+        return function(object) {
+          if (object == null) {
+            return false;
+          }
+          return object[key] === value && (value !== undefined || (key in toObject(object)));
         };
-      }());
-    }
-
-    /**
-     * The base implementation of `_.createCallback` without support for creating
-     * "_.pluck" or "_.where" style callbacks.
-     *
-     * @private
-     * @param {*} [func=identity] The value to convert to a callback.
-     * @param {*} [thisArg] The `this` binding of the created callback.
-     * @param {number} [argCount] The number of arguments the callback accepts.
-     * @returns {Function} Returns a callback function.
-     */
-    function baseCreateCallback(func, thisArg, argCount) {
+      }
+      return function(object) {
+        return baseIsMatch(object, matchData);
+      };
+    }
+
+    /**
+     * The base implementation of `_.matchesProperty` which does not clone `srcValue`.
+     *
+     * @private
+     * @param {string} path The path of the property to get.
+     * @param {*} srcValue The value to compare.
+     * @returns {Function} Returns the new function.
+     */
+    function baseMatchesProperty(path, srcValue) {
+      var isArr = isArray(path),
+          isCommon = isKey(path) && isStrictComparable(srcValue),
+          pathKey = (path + '');
+
+      path = toPath(path);
+      return function(object) {
+        if (object == null) {
+          return false;
+        }
+        var key = pathKey;
+        object = toObject(object);
+        if ((isArr || !isCommon) && !(key in object)) {
+          object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+          if (object == null) {
+            return false;
+          }
+          key = last(path);
+          object = toObject(object);
+        }
+        return object[key] === srcValue
+          ? (srcValue !== undefined || (key in object))
+          : baseIsEqual(srcValue, object[key], undefined, true);
+      };
+    }
+
+    /**
+     * The base implementation of `_.merge` without support for argument juggling,
+     * multiple sources, and `this` binding `customizer` functions.
+     *
+     * @private
+     * @param {Object} object The destination object.
+     * @param {Object} source The source object.
+     * @param {Function} [customizer] The function to customize merged values.
+     * @param {Array} [stackA=[]] Tracks traversed source objects.
+     * @param {Array} [stackB=[]] Associates values with source counterparts.
+     * @returns {Object} Returns `object`.
+     */
+    function baseMerge(object, source, customizer, stackA, stackB) {
+      if (!isObject(object)) {
+        return object;
+      }
+      var isSrcArr = isArrayLike(source) && (isArray(source) || isTypedArray(source)),
+          props = isSrcArr ? undefined : keys(source);
+
+      arrayEach(props || source, function(srcValue, key) {
+        if (props) {
+          key = srcValue;
+          srcValue = source[key];
+        }
+        if (isObjectLike(srcValue)) {
+          stackA || (stackA = []);
+          stackB || (stackB = []);
+          baseMergeDeep(object, source, key, baseMerge, customizer, stackA, stackB);
+        }
+        else {
+          var value = object[key],
+              result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
+              isCommon = result === undefined;
+
+          if (isCommon) {
+            result = srcValue;
+          }
+          if ((result !== undefined || (isSrcArr && !(key in object))) &&
+              (isCommon || (result === result ? (result !== value) : (value === value)))) {
+            object[key] = result;
+          }
+        }
+      });
+      return object;
+    }
+
+    /**
+     * A specialized version of `baseMerge` for arrays and objects which performs
+     * deep merges and tracks traversed objects enabling objects with circular
+     * references to be merged.
+     *
+     * @private
+     * @param {Object} object The destination object.
+     * @param {Object} source The source object.
+     * @param {string} key The key of the value to merge.
+     * @param {Function} mergeFunc The function to merge values.
+     * @param {Function} [customizer] The function to customize merged values.
+     * @param {Array} [stackA=[]] Tracks traversed source objects.
+     * @param {Array} [stackB=[]] Associates values with source counterparts.
+     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
+     */
+    function baseMergeDeep(object, source, key, mergeFunc, customizer, stackA, stackB) {
+      var length = stackA.length,
+          srcValue = source[key];
+
+      while (length--) {
+        if (stackA[length] == srcValue) {
+          object[key] = stackB[length];
+          return;
+        }
+      }
+      var value = object[key],
+          result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
+          isCommon = result === undefined;
+
+      if (isCommon) {
+        result = srcValue;
+        if (isArrayLike(srcValue) && (isArray(srcValue) || isTypedArray(srcValue))) {
+          result = isArray(value)
+            ? value
+            : (isArrayLike(value) ? arrayCopy(value) : []);
+        }
+        else if (isPlainObject(srcValue) || isArguments(srcValue)) {
+          result = isArguments(value)
+            ? toPlainObject(value)
+            : (isPlainObject(value) ? value : {});
+        }
+        else {
+          isCommon = false;
+        }
+      }
+      // Add the source value to the stack of traversed objects and associate
+      // it with its merged value.
+      stackA.push(srcValue);
+      stackB.push(result);
+
+      if (isCommon) {
+        // Recursively merge objects and arrays (susceptible to call stack limits).
+        object[key] = mergeFunc(result, srcValue, customizer, stackA, stackB);
+      } else if (result === result ? (result !== value) : (value === value)) {
+        object[key] = result;
+      }
+    }
+
+    /**
+     * The base implementation of `_.property` without support for deep paths.
+     *
+     * @private
+     * @param {string} key The key of the property to get.
+     * @returns {Function} Returns the new function.
+     */
+    function baseProperty(key) {
+      return function(object) {
+        return object == null ? undefined : object[key];
+      };
+    }
+
+    /**
+     * A specialized version of `baseProperty` which supports deep paths.
+     *
+     * @private
+     * @param {Array|string} path The path of the property to get.
+     * @returns {Function} Returns the new function.
+     */
+    function basePropertyDeep(path) {
+      var pathKey = (path + '');
+      path = toPath(path);
+      return function(object) {
+        return baseGet(object, path, pathKey);
+      };
+    }
+
+    /**
+     * The base implementation of `_.pullAt` without support for individual
+     * index arguments and capturing the removed elements.
+     *
+     * @private
+     * @param {Array} array The array to modify.
+     * @param {number[]} indexes The indexes of elements to remove.
+     * @returns {Array} Returns `array`.
+     */
+    function basePullAt(array, indexes) {
+      var length = array ? indexes.length : 0;
+      while (length--) {
+        var index = indexes[length];
+        if (index != previous && isIndex(index)) {
+          var previous = index;
+          splice.call(array, index, 1);
+        }
+      }
+      return array;
+    }
+
+    /**
+     * The base implementation of `_.random` without support for argument juggling
+     * and returning floating-point numbers.
+     *
+     * @private
+     * @param {number} min The minimum possible value.
+     * @param {number} max The maximum possible value.
+     * @returns {number} Returns the random number.
+     */
+    function baseRandom(min, max) {
+      return min + nativeFloor(nativeRandom() * (max - min + 1));
+    }
+
+    /**
+     * The base implementation of `_.reduce` and `_.reduceRight` without support
+     * for callback shorthands and `this` binding, which iterates over `collection`
+     * using the provided `eachFunc`.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {*} accumulator The initial value.
+     * @param {boolean} initFromCollection Specify using the first or last element
+     *  of `collection` as the initial value.
+     * @param {Function} eachFunc The function to iterate over `collection`.
+     * @returns {*} Returns the accumulated value.
+     */
+    function baseReduce(collection, iteratee, accumulator, initFromCollection, eachFunc) {
+      eachFunc(collection, function(value, index, collection) {
+        accumulator = initFromCollection
+          ? (initFromCollection = false, value)
+          : iteratee(accumulator, value, index, collection);
+      });
+      return accumulator;
+    }
+
+    /**
+     * The base implementation of `setData` without support for hot loop detection.
+     *
+     * @private
+     * @param {Function} func The function to associate metadata with.
+     * @param {*} data The metadata.
+     * @returns {Function} Returns `func`.
+     */
+    var baseSetData = !metaMap ? identity : function(func, data) {
+      metaMap.set(func, data);
+      return func;
+    };
+
+    /**
+     * The base implementation of `_.slice` without an iteratee call guard.
+     *
+     * @private
+     * @param {Array} array The array to slice.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns the slice of `array`.
+     */
+    function baseSlice(array, start, end) {
+      var index = -1,
+          length = array.length;
+
+      start = start == null ? 0 : (+start || 0);
+      if (start < 0) {
+        start = -start > length ? 0 : (length + start);
+      }
+      end = (end === undefined || end > length) ? length : (+end || 0);
+      if (end < 0) {
+        end += length;
+      }
+      length = start > end ? 0 : ((end - start) >>> 0);
+      start >>>= 0;
+
+      var result = Array(length);
+      while (++index < length) {
+        result[index] = array[index + start];
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.some` without support for callback shorthands
+     * and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {boolean} Returns `true` if any element passes the predicate check,
+     *  else `false`.
+     */
+    function baseSome(collection, predicate) {
+      var result;
+
+      baseEach(collection, function(value, index, collection) {
+        result = predicate(value, index, collection);
+        return !result;
+      });
+      return !!result;
+    }
+
+    /**
+     * The base implementation of `_.sortBy` which uses `comparer` to define
+     * the sort order of `array` and replaces criteria objects with their
+     * corresponding values.
+     *
+     * @private
+     * @param {Array} array The array to sort.
+     * @param {Function} comparer The function to define sort order.
+     * @returns {Array} Returns `array`.
+     */
+    function baseSortBy(array, comparer) {
+      var length = array.length;
+
+      array.sort(comparer);
+      while (length--) {
+        array[length] = array[length].value;
+      }
+      return array;
+    }
+
+    /**
+     * The base implementation of `_.sortByOrder` without param guards.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
+     * @param {boolean[]} orders The sort orders of `iteratees`.
+     * @returns {Array} Returns the new sorted array.
+     */
+    function baseSortByOrder(collection, iteratees, orders) {
+      var callback = getCallback(),
+          index = -1;
+
+      iteratees = arrayMap(iteratees, function(iteratee) { return callback(iteratee); });
+
+      var result = baseMap(collection, function(value) {
+        var criteria = arrayMap(iteratees, function(iteratee) { return iteratee(value); });
+        return { 'criteria': criteria, 'index': ++index, 'value': value };
+      });
+
+      return baseSortBy(result, function(object, other) {
+        return compareMultiple(object, other, orders);
+      });
+    }
+
+    /**
+     * The base implementation of `_.sum` without support for callback shorthands
+     * and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {number} Returns the sum.
+     */
+    function baseSum(collection, iteratee) {
+      var result = 0;
+      baseEach(collection, function(value, index, collection) {
+        result += +iteratee(value, index, collection) || 0;
+      });
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.uniq` without support for callback shorthands
+     * and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to inspect.
+     * @param {Function} [iteratee] The function invoked per iteration.
+     * @returns {Array} Returns the new duplicate free array.
+     */
+    function baseUniq(array, iteratee) {
+      var index = -1,
+          indexOf = getIndexOf(),
+          length = array.length,
+          isCommon = indexOf === baseIndexOf,
+          isLarge = isCommon && length >= LARGE_ARRAY_SIZE,
+          seen = isLarge ? createCache() : null,
+          result = [];
+
+      if (seen) {
+        indexOf = cacheIndexOf;
+        isCommon = false;
+      } else {
+        isLarge = false;
+        seen = iteratee ? [] : result;
+      }
+      outer:
+      while (++index < length) {
+        var value = array[index],
+            computed = iteratee ? iteratee(value, index, array) : value;
+
+        if (isCommon && value === value) {
+          var seenIndex = seen.length;
+          while (seenIndex--) {
+            if (seen[seenIndex] === computed) {
+              continue outer;
+            }
+          }
+          if (iteratee) {
+            seen.push(computed);
+          }
+          result.push(value);
+        }
+        else if (indexOf(seen, computed, 0) < 0) {
+          if (iteratee || isLarge) {
+            seen.push(computed);
+          }
+          result.push(value);
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.values` and `_.valuesIn` which creates an
+     * array of `object` property values corresponding to the property names
+     * of `props`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Array} props The property names to get values for.
+     * @returns {Object} Returns the array of property values.
+     */
+    function baseValues(object, props) {
+      var index = -1,
+          length = props.length,
+          result = Array(length);
+
+      while (++index < length) {
+        result[index] = object[props[index]];
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.dropRightWhile`, `_.dropWhile`, `_.takeRightWhile`,
+     * and `_.takeWhile` without support for callback shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to query.
+     * @param {Function} predicate The function invoked per iteration.
+     * @param {boolean} [isDrop] Specify dropping elements instead of taking them.
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Array} Returns the slice of `array`.
+     */
+    function baseWhile(array, predicate, isDrop, fromRight) {
+      var length = array.length,
+          index = fromRight ? length : -1;
+
+      while ((fromRight ? index-- : ++index < length) && predicate(array[index], index, array)) {}
+      return isDrop
+        ? baseSlice(array, (fromRight ? 0 : index), (fromRight ? index + 1 : length))
+        : baseSlice(array, (fromRight ? index + 1 : 0), (fromRight ? length : index));
+    }
+
+    /**
+     * The base implementation of `wrapperValue` which returns the result of
+     * performing a sequence of actions on the unwrapped `value`, where each
+     * successive action is supplied the return value of the previous.
+     *
+     * @private
+     * @param {*} value The unwrapped value.
+     * @param {Array} actions Actions to peform to resolve the unwrapped value.
+     * @returns {*} Returns the resolved value.
+     */
+    function baseWrapperValue(value, actions) {
+      var result = value;
+      if (result instanceof LazyWrapper) {
+        result = result.value();
+      }
+      var index = -1,
+          length = actions.length;
+
+      while (++index < length) {
+        var action = actions[index];
+        result = action.func.apply(action.thisArg, arrayPush([result], action.args));
+      }
+      return result;
+    }
+
+    /**
+     * Performs a binary search of `array` to determine the index at which `value`
+     * should be inserted into `array` in order to maintain its sort order.
+     *
+     * @private
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {boolean} [retHighest] Specify returning the highest qualified index.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
+     */
+    function binaryIndex(array, value, retHighest) {
+      var low = 0,
+          high = array ? array.length : low;
+
+      if (typeof value == 'number' && value === value && high <= HALF_MAX_ARRAY_LENGTH) {
+        while (low < high) {
+          var mid = (low + high) >>> 1,
+              computed = array[mid];
+
+          if ((retHighest ? (computed <= value) : (computed < value)) && computed !== null) {
+            low = mid + 1;
+          } else {
+            high = mid;
+          }
+        }
+        return high;
+      }
+      return binaryIndexBy(array, value, identity, retHighest);
+    }
+
+    /**
+     * This function is like `binaryIndex` except that it invokes `iteratee` for
+     * `value` and each element of `array` to compute their sort ranking. The
+     * iteratee is invoked with one argument; (value).
+     *
+     * @private
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {boolean} [retHighest] Specify returning the highest qualified index.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
+     */
+    function binaryIndexBy(array, value, iteratee, retHighest) {
+      value = iteratee(value);
+
+      var low = 0,
+          high = array ? array.length : 0,
+          valIsNaN = value !== value,
+          valIsNull = value === null,
+          valIsUndef = value === undefined;
+
+      while (low < high) {
+        var mid = nativeFloor((low + high) / 2),
+            computed = iteratee(array[mid]),
+            isDef = computed !== undefined,
+            isReflexive = computed === computed;
+
+        if (valIsNaN) {
+          var setLow = isReflexive || retHighest;
+        } else if (valIsNull) {
+          setLow = isReflexive && isDef && (retHighest || computed != null);
+        } else if (valIsUndef) {
+          setLow = isReflexive && (retHighest || isDef);
+        } else if (computed == null) {
+          setLow = false;
+        } else {
+          setLow = retHighest ? (computed <= value) : (computed < value);
+        }
+        if (setLow) {
+          low = mid + 1;
+        } else {
+          high = mid;
+        }
+      }
+      return nativeMin(high, MAX_ARRAY_INDEX);
+    }
+
+    /**
+     * A specialized version of `baseCallback` which only supports `this` binding
+     * and specifying the number of arguments to provide to `func`.
+     *
+     * @private
+     * @param {Function} func The function to bind.
+     * @param {*} thisArg The `this` binding of `func`.
+     * @param {number} [argCount] The number of arguments to provide to `func`.
+     * @returns {Function} Returns the callback.
+     */
+    function bindCallback(func, thisArg, argCount) {
       if (typeof func != 'function') {
         return identity;
       }
-      // exit early for no `thisArg` or already bound by `Function#bind`
-      if (typeof thisArg == 'undefined' || !('prototype' in func)) {
-        return func;
-      }
-      var bindData = func.__bindData__;
-      if (typeof bindData == 'undefined') {
-        if (support.funcNames) {
-          bindData = !func.name;
-        }
-        bindData = bindData || !support.funcDecomp;
-        if (!bindData) {
-          var source = fnToString.call(func);
-          if (!support.funcNames) {
-            bindData = !reFuncName.test(source);
-          }
-          if (!bindData) {
-            // checks if `func` references the `this` keyword and stores the result
-            bindData = reThis.test(source);
-            setBindData(func, bindData);
-          }
-        }
-      }
-      // exit early if there are no `this` references or `func` is bound
-      if (bindData === false || (bindData !== true && bindData[1] & 1)) {
+      if (thisArg === undefined) {
         return func;
       }
       switch (argCount) {
         case 1: return function(value) {
           return func.call(thisArg, value);
         };
-        case 2: return function(a, b) {
-          return func.call(thisArg, a, b);
-        };
         case 3: return function(value, index, collection) {
           return func.call(thisArg, value, index, collection);
         };
         case 4: return function(accumulator, value, index, collection) {
           return func.call(thisArg, accumulator, value, index, collection);
         };
-      }
-      return bind(func, thisArg);
-    }
-
-    /**
-     * The base implementation of `createWrapper` that creates the wrapper and
-     * sets its meta data.
-     *
-     * @private
-     * @param {Array} bindData The bind data array.
-     * @returns {Function} Returns the new function.
-     */
-    function baseCreateWrapper(bindData) {
-      var func = bindData[0],
-          bitmask = bindData[1],
-          partialArgs = bindData[2],
-          partialRightArgs = bindData[3],
-          thisArg = bindData[4],
-          arity = bindData[5];
-
-      var isBind = bitmask & 1,
-          isBindKey = bitmask & 2,
-          isCurry = bitmask & 4,
-          isCurryBound = bitmask & 8,
-          key = func;
-
-      function bound() {
-        var thisBinding = isBind ? thisArg : this;
-        if (partialArgs) {
-          var args = slice(partialArgs);
-          push.apply(args, arguments);
-        }
-        if (partialRightArgs || isCurry) {
-          args || (args = slice(arguments));
-          if (partialRightArgs) {
-            push.apply(args, partialRightArgs);
-          }
-          if (isCurry && args.length < arity) {
-            bitmask |= 16 & ~32;
-            return baseCreateWrapper([func, (isCurryBound ? bitmask : bitmask & ~3), args, null, thisArg, arity]);
-          }
-        }
-        args || (args = arguments);
-        if (isBindKey) {
-          func = thisBinding[key];
-        }
-        if (this instanceof bound) {
-          thisBinding = baseCreate(func.prototype);
-          var result = func.apply(thisBinding, args);
-          return isObject(result) ? result : thisBinding;
-        }
-        return func.apply(thisBinding, args);
-      }
-      setBindData(bound, bindData);
-      return bound;
-    }
-
-    /**
-     * The base implementation of `_.difference` that accepts a single array
-     * of values to exclude.
-     *
-     * @private
-     * @param {Array} array The array to process.
-     * @param {Array} [values] The array of values to exclude.
-     * @returns {Array} Returns a new array of filtered values.
-     */
-    function baseDifference(array, values) {
-      var index = -1,
-          indexOf = getIndexOf(),
-          length = array ? array.length : 0,
-          isLarge = length >= largeArraySize && indexOf === baseIndexOf,
-          result = [];
-
-      if (isLarge) {
-        var cache = createCache(values);
-        if (cache) {
-          indexOf = cacheIndexOf;
-          values = cache;
-        } else {
-          isLarge = false;
-        }
-      }
-      while (++index < length) {
-        var value = array[index];
-        if (indexOf(values, value) < 0) {
-          result.push(value);
-        }
-      }
-      if (isLarge) {
-        releaseObject(values);
-      }
+        case 5: return function(value, other, key, object, source) {
+          return func.call(thisArg, value, other, key, object, source);
+        };
+      }
+      return function() {
+        return func.apply(thisArg, arguments);
+      };
+    }
+
+    /**
+     * Creates a clone of the given array buffer.
+     *
+     * @private
+     * @param {ArrayBuffer} buffer The array buffer to clone.
+     * @returns {ArrayBuffer} Returns the cloned array buffer.
+     */
+    function bufferClone(buffer) {
+      var result = new ArrayBuffer(buffer.byteLength),
+          view = new Uint8Array(result);
+
+      view.set(new Uint8Array(buffer));
       return result;
     }
 
     /**
-     * The base implementation of `_.flatten` without support for callback
-     * shorthands or `thisArg` binding.
-     *
-     * @private
-     * @param {Array} array The array to flatten.
-     * @param {boolean} [isShallow=false] A flag to restrict flattening to a single level.
-     * @param {boolean} [isStrict=false] A flag to restrict flattening to arrays and `arguments` objects.
-     * @param {number} [fromIndex=0] The index to start from.
-     * @returns {Array} Returns a new flattened array.
-     */
-    function baseFlatten(array, isShallow, isStrict, fromIndex) {
-      var index = (fromIndex || 0) - 1,
-          length = array ? array.length : 0,
-          result = [];
-
-      while (++index < length) {
-        var value = array[index];
-
-        if (value && typeof value == 'object' && typeof value.length == 'number'
-            && (isArray(value) || isArguments(value))) {
-          // recursively flatten arrays (susceptible to call stack limits)
-          if (!isShallow) {
-            value = baseFlatten(value, isShallow, isStrict);
-          }
-          var valIndex = -1,
-              valLength = value.length,
-              resIndex = result.length;
-
-          result.length += valLength;
-          while (++valIndex < valLength) {
-            result[resIndex++] = value[valIndex];
-          }
-        } else if (!isStrict) {
-          result.push(value);
-        }
+     * Creates an array that is the composition of partially applied arguments,
+     * placeholders, and provided arguments into a single array of arguments.
+     *
+     * @private
+     * @param {Array|Object} args The provided arguments.
+     * @param {Array} partials The arguments to prepend to those provided.
+     * @param {Array} holders The `partials` placeholder indexes.
+     * @returns {Array} Returns the new array of composed arguments.
+     */
+    function composeArgs(args, partials, holders) {
+      var holdersLength = holders.length,
+          argsIndex = -1,
+          argsLength = nativeMax(args.length - holdersLength, 0),
+          leftIndex = -1,
+          leftLength = partials.length,
+          result = Array(leftLength + argsLength);
+
+      while (++leftIndex < leftLength) {
+        result[leftIndex] = partials[leftIndex];
+      }
+      while (++argsIndex < holdersLength) {
+        result[holders[argsIndex]] = args[argsIndex];
+      }
+      while (argsLength--) {
+        result[leftIndex++] = args[argsIndex++];
       }
       return result;
     }
 
     /**
-     * The base implementation of `_.isEqual`, without support for `thisArg` binding,
-     * that allows partial "_.where" style comparisons.
-     *
-     * @private
-     * @param {*} a The value to compare.
-     * @param {*} b The other value to compare.
-     * @param {Function} [callback] The function to customize comparing values.
-     * @param {Function} [isWhere=false] A flag to indicate performing partial comparisons.
-     * @param {Array} [stackA=[]] Tracks traversed `a` objects.
-     * @param {Array} [stackB=[]] Tracks traversed `b` objects.
-     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
-     */
-    function baseIsEqual(a, b, callback, isWhere, stackA, stackB) {
-      // used to indicate that when comparing objects, `a` has at least the properties of `b`
-      if (callback) {
-        var result = callback(a, b);
-        if (typeof result != 'undefined') {
-          return !!result;
-        }
-      }
-      // exit early for identical values
-      if (a === b) {
-        // treat `+0` vs. `-0` as not equal
-        return a !== 0 || (1 / a == 1 / b);
-      }
-      var type = typeof a,
-          otherType = typeof b;
-
-      // exit early for unlike primitive values
-      if (a === a &&
-          !(a && objectTypes[type]) &&
-          !(b && objectTypes[otherType])) {
-        return false;
-      }
-      // exit early for `null` and `undefined` avoiding ES3's Function#call behavior
-      // http://es5.github.io/#x15.3.4.4
-      if (a == null || b == null) {
-        return a === b;
-      }
-      // compare [[Class]] names
-      var className = toString.call(a),
-          otherClass = toString.call(b);
-
-      if (className == argsClass) {
-        className = objectClass;
-      }
-      if (otherClass == argsClass) {
-        otherClass = objectClass;
-      }
-      if (className != otherClass) {
-        return false;
-      }
-      switch (className) {
-        case boolClass:
-        case dateClass:
-          // coerce dates and booleans to numbers, dates to milliseconds and booleans
-          // to `1` or `0` treating invalid dates coerced to `NaN` as not equal
-          return +a == +b;
-
-        case numberClass:
-          // treat `NaN` vs. `NaN` as equal
-          return (a != +a)
-            ? b != +b
-            // but treat `+0` vs. `-0` as not equal
-            : (a == 0 ? (1 / a == 1 / b) : a == +b);
-
-        case regexpClass:
-        case stringClass:
-          // coerce regexes to strings (http://es5.github.io/#x15.10.6.4)
-          // treat string primitives and their corresponding object instances as equal
-          return a == String(b);
-      }
-      var isArr = className == arrayClass;
-      if (!isArr) {
-        // unwrap any `lodash` wrapped values
-        var aWrapped = hasOwnProperty.call(a, '__wrapped__'),
-            bWrapped = hasOwnProperty.call(b, '__wrapped__');
-
-        if (aWrapped || bWrapped) {
-          return baseIsEqual(aWrapped ? a.__wrapped__ : a, bWrapped ? b.__wrapped__ : b, callback, isWhere, stackA, stackB);
-        }
-        // exit for functions and DOM nodes
-        if (className != objectClass) {
-          return false;
-        }
-        // in older versions of Opera, `arguments` objects have `Array` constructors
-        var ctorA = a.constructor,
-            ctorB = b.constructor;
-
-        // non `Object` object instances with different constructors are not equal
-        if (ctorA != ctorB &&
-              !(isFunction(ctorA) && ctorA instanceof ctorA && isFunction(ctorB) && ctorB instanceof ctorB) &&
-              ('constructor' in a && 'constructor' in b)
-            ) {
-          return false;
-        }
-      }
-      // assume cyclic structures are equal
-      // the algorithm for detecting cyclic structures is adapted from ES 5.1
-      // section 15.12.3, abstract operation `JO` (http://es5.github.io/#x15.12.3)
-      var initedStack = !stackA;
-      stackA || (stackA = getArray());
-      stackB || (stackB = getArray());
-
-      var length = stackA.length;
-      while (length--) {
-        if (stackA[length] == a) {
-          return stackB[length] == b;
-        }
-      }
-      var size = 0;
-      result = true;
-
-      // add `a` and `b` to the stack of traversed objects
-      stackA.push(a);
-      stackB.push(b);
-
-      // recursively compare objects and arrays (susceptible to call stack limits)
-      if (isArr) {
-        // compare lengths to determine if a deep comparison is necessary
-        length = a.length;
-        size = b.length;
-        result = size == length;
-
-        if (result || isWhere) {
-          // deep compare the contents, ignoring non-numeric properties
-          while (size--) {
-            var index = length,
-                value = b[size];
-
-            if (isWhere) {
-              while (index--) {
-                if ((result = baseIsEqual(a[index], value, callback, isWhere, stackA, stackB))) {
-                  break;
-                }
-              }
-            } else if (!(result = baseIsEqual(a[size], value, callback, isWhere, stackA, stackB))) {
-              break;
-            }
-          }
-        }
-      }
-      else {
-        // deep compare objects using `forIn`, instead of `forOwn`, to avoid `Object.keys`
-        // which, in this case, is more costly
-        forIn(b, function(value, key, b) {
-          if (hasOwnProperty.call(b, key)) {
-            // count the number of properties.
-            size++;
-            // deep compare each property value.
-            return (result = hasOwnProperty.call(a, key) && baseIsEqual(a[key], value, callback, isWhere, stackA, stackB));
-          }
-        });
-
-        if (result && !isWhere) {
-          // ensure both objects have the same number of properties
-          forIn(a, function(value, key, a) {
-            if (hasOwnProperty.call(a, key)) {
-              // `size` will be `-1` if `a` has more properties than `b`
-              return (result = --size > -1);
-            }
-          });
-        }
-      }
-      stackA.pop();
-      stackB.pop();
-
-      if (initedStack) {
-        releaseArray(stackA);
-        releaseArray(stackB);
+     * This function is like `composeArgs` except that the arguments composition
+     * is tailored for `_.partialRight`.
+     *
+     * @private
+     * @param {Array|Object} args The provided arguments.
+     * @param {Array} partials The arguments to append to those provided.
+     * @param {Array} holders The `partials` placeholder indexes.
+     * @returns {Array} Returns the new array of composed arguments.
+     */
+    function composeArgsRight(args, partials, holders) {
+      var holdersIndex = -1,
+          holdersLength = holders.length,
+          argsIndex = -1,
+          argsLength = nativeMax(args.length - holdersLength, 0),
+          rightIndex = -1,
+          rightLength = partials.length,
+          result = Array(argsLength + rightLength);
+
+      while (++argsIndex < argsLength) {
+        result[argsIndex] = args[argsIndex];
+      }
+      var offset = argsIndex;
+      while (++rightIndex < rightLength) {
+        result[offset + rightIndex] = partials[rightIndex];
+      }
+      while (++holdersIndex < holdersLength) {
+        result[offset + holders[holdersIndex]] = args[argsIndex++];
       }
       return result;
     }
 
     /**
-     * The base implementation of `_.merge` without argument juggling or support
-     * for `thisArg` binding.
-     *
-     * @private
-     * @param {Object} object The destination object.
-     * @param {Object} source The source object.
-     * @param {Function} [callback] The function to customize merging properties.
-     * @param {Array} [stackA=[]] Tracks traversed source objects.
-     * @param {Array} [stackB=[]] Associates values with source counterparts.
-     */
-    function baseMerge(object, source, callback, stackA, stackB) {
-      (isArray(source) ? forEach : forOwn)(source, function(source, key) {
-        var found,
-            isArr,
-            result = source,
-            value = object[key];
-
-        if (source && ((isArr = isArray(source)) || isPlainObject(source))) {
-          // avoid merging previously merged cyclic sources
-          var stackLength = stackA.length;
-          while (stackLength--) {
-            if ((found = stackA[stackLength] == source)) {
-              value = stackB[stackLength];
-              break;
-            }
-          }
-          if (!found) {
-            var isShallow;
-            if (callback) {
-              result = callback(value, source);
-              if ((isShallow = typeof result != 'undefined')) {
-                value = result;
-              }
-            }
-            if (!isShallow) {
-              value = isArr
-                ? (isArray(value) ? value : [])
-                : (isPlainObject(value) ? value : {});
-            }
-            // add `source` and associated `value` to the stack of traversed objects
-            stackA.push(source);
-            stackB.push(value);
-
-            // recursively merge objects and arrays (susceptible to call stack limits)
-            if (!isShallow) {
-              baseMerge(value, source, callback, stackA, stackB);
-            }
-          }
-        }
-        else {
-          if (callback) {
-            result = callback(value, source);
-            if (typeof result == 'undefined') {
-              result = source;
-            }
-          }
-          if (typeof result != 'undefined') {
-            value = result;
-          }
-        }
-        object[key] = value;
-      });
-    }
-
-    /**
-     * The base implementation of `_.random` without argument juggling or support
-     * for returning floating-point numbers.
-     *
-     * @private
-     * @param {number} min The minimum possible value.
-     * @param {number} max The maximum possible value.
-     * @returns {number} Returns a random number.
-     */
-    function baseRandom(min, max) {
-      return min + floor(nativeRandom() * (max - min + 1));
-    }
-
-    /**
-     * The base implementation of `_.uniq` without support for callback shorthands
-     * or `thisArg` binding.
-     *
-     * @private
-     * @param {Array} array The array to process.
-     * @param {boolean} [isSorted=false] A flag to indicate that `array` is sorted.
-     * @param {Function} [callback] The function called per iteration.
-     * @returns {Array} Returns a duplicate-value-free array.
-     */
-    function baseUniq(array, isSorted, callback) {
-      var index = -1,
-          indexOf = getIndexOf(),
-          length = array ? array.length : 0,
-          result = [];
-
-      var isLarge = !isSorted && length >= largeArraySize && indexOf === baseIndexOf,
-          seen = (callback || isLarge) ? getArray() : result;
-
-      if (isLarge) {
-        var cache = createCache(seen);
-        indexOf = cacheIndexOf;
-        seen = cache;
-      }
-      while (++index < length) {
-        var value = array[index],
-            computed = callback ? callback(value, index, array) : value;
-
-        if (isSorted
-              ? !index || seen[seen.length - 1] !== computed
-              : indexOf(seen, computed) < 0
-            ) {
-          if (callback || isLarge) {
-            seen.push(computed);
-          }
-          result.push(value);
-        }
-      }
-      if (isLarge) {
-        releaseArray(seen.array);
-        releaseObject(seen);
-      } else if (callback) {
-        releaseArray(seen);
-      }
-      return result;
-    }
-
-    /**
-     * Creates a function that aggregates a collection, creating an object composed
-     * of keys generated from the results of running each element of the collection
-     * through a callback. The given `setter` function sets the keys and values
-     * of the composed object.
-     *
-     * @private
-     * @param {Function} setter The setter function.
+     * Creates a `_.countBy`, `_.groupBy`, `_.indexBy`, or `_.partition` function.
+     *
+     * @private
+     * @param {Function} setter The function to set keys and values of the accumulator object.
+     * @param {Function} [initializer] The function to initialize the accumulator object.
      * @returns {Function} Returns the new aggregator function.
      */
-    function createAggregator(setter) {
-      return function(collection, callback, thisArg) {
-        var result = {};
-        callback = lodash.createCallback(callback, thisArg, 3);
-
-        var index = -1,
-            length = collection ? collection.length : 0;
-
-        if (typeof length == 'number') {
+    function createAggregator(setter, initializer) {
+      return function(collection, iteratee, thisArg) {
+        var result = initializer ? initializer() : {};
+        iteratee = getCallback(iteratee, thisArg, 3);
+
+        if (isArray(collection)) {
+          var index = -1,
+              length = collection.length;
+
           while (++index < length) {
             var value = collection[index];
-            setter(result, value, callback(value, index, collection), collection);
+            setter(result, value, iteratee(value, index, collection), collection);
           }
         } else {
-          forOwn(collection, function(value, key, collection) {
-            setter(result, value, callback(value, key, collection), collection);
+          baseEach(collection, function(value, key, collection) {
+            setter(result, value, iteratee(value, key, collection), collection);
           });
         }
         return result;
@@ -1370,2054 +2993,3621 @@
     }
 
     /**
-     * Creates a function that, when called, either curries or invokes `func`
-     * with an optional `this` binding and partially applied arguments.
+     * Creates a `_.assign`, `_.defaults`, or `_.merge` function.
+     *
+     * @private
+     * @param {Function} assigner The function to assign values.
+     * @returns {Function} Returns the new assigner function.
+     */
+    function createAssigner(assigner) {
+      return restParam(function(object, sources) {
+        var index = -1,
+            length = object == null ? 0 : sources.length,
+            customizer = length > 2 ? sources[length - 2] : undefined,
+            guard = length > 2 ? sources[2] : undefined,
+            thisArg = length > 1 ? sources[length - 1] : undefined;
+
+        if (typeof customizer == 'function') {
+          customizer = bindCallback(customizer, thisArg, 5);
+          length -= 2;
+        } else {
+          customizer = typeof thisArg == 'function' ? thisArg : undefined;
+          length -= (customizer ? 1 : 0);
+        }
+        if (guard && isIterateeCall(sources[0], sources[1], guard)) {
+          customizer = length < 3 ? undefined : customizer;
+          length = 1;
+        }
+        while (++index < length) {
+          var source = sources[index];
+          if (source) {
+            assigner(object, source, customizer);
+          }
+        }
+        return object;
+      });
+    }
+
+    /**
+     * Creates a `baseEach` or `baseEachRight` function.
+     *
+     * @private
+     * @param {Function} eachFunc The function to iterate over a collection.
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new base function.
+     */
+    function createBaseEach(eachFunc, fromRight) {
+      return function(collection, iteratee) {
+        var length = collection ? getLength(collection) : 0;
+        if (!isLength(length)) {
+          return eachFunc(collection, iteratee);
+        }
+        var index = fromRight ? length : -1,
+            iterable = toObject(collection);
+
+        while ((fromRight ? index-- : ++index < length)) {
+          if (iteratee(iterable[index], index, iterable) === false) {
+            break;
+          }
+        }
+        return collection;
+      };
+    }
+
+    /**
+     * Creates a base function for `_.forIn` or `_.forInRight`.
+     *
+     * @private
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new base function.
+     */
+    function createBaseFor(fromRight) {
+      return function(object, iteratee, keysFunc) {
+        var iterable = toObject(object),
+            props = keysFunc(object),
+            length = props.length,
+            index = fromRight ? length : -1;
+
+        while ((fromRight ? index-- : ++index < length)) {
+          var key = props[index];
+          if (iteratee(iterable[key], key, iterable) === false) {
+            break;
+          }
+        }
+        return object;
+      };
+    }
+
+    /**
+     * Creates a function that wraps `func` and invokes it with the `this`
+     * binding of `thisArg`.
+     *
+     * @private
+     * @param {Function} func The function to bind.
+     * @param {*} [thisArg] The `this` binding of `func`.
+     * @returns {Function} Returns the new bound function.
+     */
+    function createBindWrapper(func, thisArg) {
+      var Ctor = createCtorWrapper(func);
+
+      function wrapper() {
+        var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
+        return fn.apply(thisArg, arguments);
+      }
+      return wrapper;
+    }
+
+    /**
+     * Creates a `Set` cache object to optimize linear searches of large arrays.
+     *
+     * @private
+     * @param {Array} [values] The values to cache.
+     * @returns {null|Object} Returns the new cache object if `Set` is supported, else `null`.
+     */
+    function createCache(values) {
+      return (nativeCreate && Set) ? new SetCache(values) : null;
+    }
+
+    /**
+     * Creates a function that produces compound words out of the words in a
+     * given string.
+     *
+     * @private
+     * @param {Function} callback The function to combine each word.
+     * @returns {Function} Returns the new compounder function.
+     */
+    function createCompounder(callback) {
+      return function(string) {
+        var index = -1,
+            array = words(deburr(string)),
+            length = array.length,
+            result = '';
+
+        while (++index < length) {
+          result = callback(result, array[index], index);
+        }
+        return result;
+      };
+    }
+
+    /**
+     * Creates a function that produces an instance of `Ctor` regardless of
+     * whether it was invoked as part of a `new` expression or by `call` or `apply`.
+     *
+     * @private
+     * @param {Function} Ctor The constructor to wrap.
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createCtorWrapper(Ctor) {
+      return function() {
+        // Use a `switch` statement to work with class constructors.
+        // See http://ecma-international.org/ecma-262/6.0/#sec-ecmascript-function-objects-call-thisargument-argumentslist
+        // for more details.
+        var args = arguments;
+        switch (args.length) {
+          case 0: return new Ctor;
+          case 1: return new Ctor(args[0]);
+          case 2: return new Ctor(args[0], args[1]);
+          case 3: return new Ctor(args[0], args[1], args[2]);
+          case 4: return new Ctor(args[0], args[1], args[2], args[3]);
+          case 5: return new Ctor(args[0], args[1], args[2], args[3], args[4]);
+          case 6: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5]);
+          case 7: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5], args[6]);
+        }
+        var thisBinding = baseCreate(Ctor.prototype),
+            result = Ctor.apply(thisBinding, args);
+
+        // Mimic the constructor's `return` behavior.
+        // See https://es5.github.io/#x13.2.2 for more details.
+        return isObject(result) ? result : thisBinding;
+      };
+    }
+
+    /**
+     * Creates a `_.curry` or `_.curryRight` function.
+     *
+     * @private
+     * @param {boolean} flag The curry bit flag.
+     * @returns {Function} Returns the new curry function.
+     */
+    function createCurry(flag) {
+      function curryFunc(func, arity, guard) {
+        if (guard && isIterateeCall(func, arity, guard)) {
+          arity = undefined;
+        }
+        var result = createWrapper(func, flag, undefined, undefined, undefined, undefined, undefined, arity);
+        result.placeholder = curryFunc.placeholder;
+        return result;
+      }
+      return curryFunc;
+    }
+
+    /**
+     * Creates a `_.defaults` or `_.defaultsDeep` function.
+     *
+     * @private
+     * @param {Function} assigner The function to assign values.
+     * @param {Function} customizer The function to customize assigned values.
+     * @returns {Function} Returns the new defaults function.
+     */
+    function createDefaults(assigner, customizer) {
+      return restParam(function(args) {
+        var object = args[0];
+        if (object == null) {
+          return object;
+        }
+        args.push(customizer);
+        return assigner.apply(undefined, args);
+      });
+    }
+
+    /**
+     * Creates a `_.max` or `_.min` function.
+     *
+     * @private
+     * @param {Function} comparator The function used to compare values.
+     * @param {*} exValue The initial extremum value.
+     * @returns {Function} Returns the new extremum function.
+     */
+    function createExtremum(comparator, exValue) {
+      return function(collection, iteratee, thisArg) {
+        if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
+          iteratee = undefined;
+        }
+        iteratee = getCallback(iteratee, thisArg, 3);
+        if (iteratee.length == 1) {
+          collection = isArray(collection) ? collection : toIterable(collection);
+          var result = arrayExtremum(collection, iteratee, comparator, exValue);
+          if (!(collection.length && result === exValue)) {
+            return result;
+          }
+        }
+        return baseExtremum(collection, iteratee, comparator, exValue);
+      };
+    }
+
+    /**
+     * Creates a `_.find` or `_.findLast` function.
+     *
+     * @private
+     * @param {Function} eachFunc The function to iterate over a collection.
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new find function.
+     */
+    function createFind(eachFunc, fromRight) {
+      return function(collection, predicate, thisArg) {
+        predicate = getCallback(predicate, thisArg, 3);
+        if (isArray(collection)) {
+          var index = baseFindIndex(collection, predicate, fromRight);
+          return index > -1 ? collection[index] : undefined;
+        }
+        return baseFind(collection, predicate, eachFunc);
+      };
+    }
+
+    /**
+     * Creates a `_.findIndex` or `_.findLastIndex` function.
+     *
+     * @private
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new find function.
+     */
+    function createFindIndex(fromRight) {
+      return function(array, predicate, thisArg) {
+        if (!(array && array.length)) {
+          return -1;
+        }
+        predicate = getCallback(predicate, thisArg, 3);
+        return baseFindIndex(array, predicate, fromRight);
+      };
+    }
+
+    /**
+     * Creates a `_.findKey` or `_.findLastKey` function.
+     *
+     * @private
+     * @param {Function} objectFunc The function to iterate over an object.
+     * @returns {Function} Returns the new find function.
+     */
+    function createFindKey(objectFunc) {
+      return function(object, predicate, thisArg) {
+        predicate = getCallback(predicate, thisArg, 3);
+        return baseFind(object, predicate, objectFunc, true);
+      };
+    }
+
+    /**
+     * Creates a `_.flow` or `_.flowRight` function.
+     *
+     * @private
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new flow function.
+     */
+    function createFlow(fromRight) {
+      return function() {
+        var wrapper,
+            length = arguments.length,
+            index = fromRight ? length : -1,
+            leftIndex = 0,
+            funcs = Array(length);
+
+        while ((fromRight ? index-- : ++index < length)) {
+          var func = funcs[leftIndex++] = arguments[index];
+          if (typeof func != 'function') {
+            throw new TypeError(FUNC_ERROR_TEXT);
+          }
+          if (!wrapper && LodashWrapper.prototype.thru && getFuncName(func) == 'wrapper') {
+            wrapper = new LodashWrapper([], true);
+          }
+        }
+        index = wrapper ? -1 : length;
+        while (++index < length) {
+          func = funcs[index];
+
+          var funcName = getFuncName(func),
+              data = funcName == 'wrapper' ? getData(func) : undefined;
+
+          if (data && isLaziable(data[0]) && data[1] == (ARY_FLAG | CURRY_FLAG | PARTIAL_FLAG | REARG_FLAG) && !data[4].length && data[9] == 1) {
+            wrapper = wrapper[getFuncName(data[0])].apply(wrapper, data[3]);
+          } else {
+            wrapper = (func.length == 1 && isLaziable(func)) ? wrapper[funcName]() : wrapper.thru(func);
+          }
+        }
+        return function() {
+          var args = arguments,
+              value = args[0];
+
+          if (wrapper && args.length == 1 && isArray(value) && value.length >= LARGE_ARRAY_SIZE) {
+            return wrapper.plant(value).value();
+          }
+          var index = 0,
+              result = length ? funcs[index].apply(this, args) : value;
+
+          while (++index < length) {
+            result = funcs[index].call(this, result);
+          }
+          return result;
+        };
+      };
+    }
+
+    /**
+     * Creates a function for `_.forEach` or `_.forEachRight`.
+     *
+     * @private
+     * @param {Function} arrayFunc The function to iterate over an array.
+     * @param {Function} eachFunc The function to iterate over a collection.
+     * @returns {Function} Returns the new each function.
+     */
+    function createForEach(arrayFunc, eachFunc) {
+      return function(collection, iteratee, thisArg) {
+        return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
+          ? arrayFunc(collection, iteratee)
+          : eachFunc(collection, bindCallback(iteratee, thisArg, 3));
+      };
+    }
+
+    /**
+     * Creates a function for `_.forIn` or `_.forInRight`.
+     *
+     * @private
+     * @param {Function} objectFunc The function to iterate over an object.
+     * @returns {Function} Returns the new each function.
+     */
+    function createForIn(objectFunc) {
+      return function(object, iteratee, thisArg) {
+        if (typeof iteratee != 'function' || thisArg !== undefined) {
+          iteratee = bindCallback(iteratee, thisArg, 3);
+        }
+        return objectFunc(object, iteratee, keysIn);
+      };
+    }
+
+    /**
+     * Creates a function for `_.forOwn` or `_.forOwnRight`.
+     *
+     * @private
+     * @param {Function} objectFunc The function to iterate over an object.
+     * @returns {Function} Returns the new each function.
+     */
+    function createForOwn(objectFunc) {
+      return function(object, iteratee, thisArg) {
+        if (typeof iteratee != 'function' || thisArg !== undefined) {
+          iteratee = bindCallback(iteratee, thisArg, 3);
+        }
+        return objectFunc(object, iteratee);
+      };
+    }
+
+    /**
+     * Creates a function for `_.mapKeys` or `_.mapValues`.
+     *
+     * @private
+     * @param {boolean} [isMapKeys] Specify mapping keys instead of values.
+     * @returns {Function} Returns the new map function.
+     */
+    function createObjectMapper(isMapKeys) {
+      return function(object, iteratee, thisArg) {
+        var result = {};
+        iteratee = getCallback(iteratee, thisArg, 3);
+
+        baseForOwn(object, function(value, key, object) {
+          var mapped = iteratee(value, key, object);
+          key = isMapKeys ? mapped : key;
+          value = isMapKeys ? value : mapped;
+          result[key] = value;
+        });
+        return result;
+      };
+    }
+
+    /**
+     * Creates a function for `_.padLeft` or `_.padRight`.
+     *
+     * @private
+     * @param {boolean} [fromRight] Specify padding from the right.
+     * @returns {Function} Returns the new pad function.
+     */
+    function createPadDir(fromRight) {
+      return function(string, length, chars) {
+        string = baseToString(string);
+        return (fromRight ? string : '') + createPadding(string, length, chars) + (fromRight ? '' : string);
+      };
+    }
+
+    /**
+     * Creates a `_.partial` or `_.partialRight` function.
+     *
+     * @private
+     * @param {boolean} flag The partial bit flag.
+     * @returns {Function} Returns the new partial function.
+     */
+    function createPartial(flag) {
+      var partialFunc = restParam(function(func, partials) {
+        var holders = replaceHolders(partials, partialFunc.placeholder);
+        return createWrapper(func, flag, undefined, partials, holders);
+      });
+      return partialFunc;
+    }
+
+    /**
+     * Creates a function for `_.reduce` or `_.reduceRight`.
+     *
+     * @private
+     * @param {Function} arrayFunc The function to iterate over an array.
+     * @param {Function} eachFunc The function to iterate over a collection.
+     * @returns {Function} Returns the new each function.
+     */
+    function createReduce(arrayFunc, eachFunc) {
+      return function(collection, iteratee, accumulator, thisArg) {
+        var initFromArray = arguments.length < 3;
+        return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
+          ? arrayFunc(collection, iteratee, accumulator, initFromArray)
+          : baseReduce(collection, getCallback(iteratee, thisArg, 4), accumulator, initFromArray, eachFunc);
+      };
+    }
+
+    /**
+     * Creates a function that wraps `func` and invokes it with optional `this`
+     * binding of, partial application, and currying.
      *
      * @private
      * @param {Function|string} func The function or method name to reference.
-     * @param {number} bitmask The bitmask of method flags to compose.
+     * @param {number} bitmask The bitmask of flags. See `createWrapper` for more details.
+     * @param {*} [thisArg] The `this` binding of `func`.
+     * @param {Array} [partials] The arguments to prepend to those provided to the new function.
+     * @param {Array} [holders] The `partials` placeholder indexes.
+     * @param {Array} [partialsRight] The arguments to append to those provided to the new function.
+     * @param {Array} [holdersRight] The `partialsRight` placeholder indexes.
+     * @param {Array} [argPos] The argument positions of the new function.
+     * @param {number} [ary] The arity cap of `func`.
+     * @param {number} [arity] The arity of `func`.
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createHybridWrapper(func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity) {
+      var isAry = bitmask & ARY_FLAG,
+          isBind = bitmask & BIND_FLAG,
+          isBindKey = bitmask & BIND_KEY_FLAG,
+          isCurry = bitmask & CURRY_FLAG,
+          isCurryBound = bitmask & CURRY_BOUND_FLAG,
+          isCurryRight = bitmask & CURRY_RIGHT_FLAG,
+          Ctor = isBindKey ? undefined : createCtorWrapper(func);
+
+      function wrapper() {
+        // Avoid `arguments` object use disqualifying optimizations by
+        // converting it to an array before providing it to other functions.
+        var length = arguments.length,
+            index = length,
+            args = Array(length);
+
+        while (index--) {
+          args[index] = arguments[index];
+        }
+        if (partials) {
+          args = composeArgs(args, partials, holders);
+        }
+        if (partialsRight) {
+          args = composeArgsRight(args, partialsRight, holdersRight);
+        }
+        if (isCurry || isCurryRight) {
+          var placeholder = wrapper.placeholder,
+              argsHolders = replaceHolders(args, placeholder);
+
+          length -= argsHolders.length;
+          if (length < arity) {
+            var newArgPos = argPos ? arrayCopy(argPos) : undefined,
+                newArity = nativeMax(arity - length, 0),
+                newsHolders = isCurry ? argsHolders : undefined,
+                newHoldersRight = isCurry ? undefined : argsHolders,
+                newPartials = isCurry ? args : undefined,
+                newPartialsRight = isCurry ? undefined : args;
+
+            bitmask |= (isCurry ? PARTIAL_FLAG : PARTIAL_RIGHT_FLAG);
+            bitmask &= ~(isCurry ? PARTIAL_RIGHT_FLAG : PARTIAL_FLAG);
+
+            if (!isCurryBound) {
+              bitmask &= ~(BIND_FLAG | BIND_KEY_FLAG);
+            }
+            var newData = [func, bitmask, thisArg, newPartials, newsHolders, newPartialsRight, newHoldersRight, newArgPos, ary, newArity],
+                result = createHybridWrapper.apply(undefined, newData);
+
+            if (isLaziable(func)) {
+              setData(result, newData);
+            }
+            result.placeholder = placeholder;
+            return result;
+          }
+        }
+        var thisBinding = isBind ? thisArg : this,
+            fn = isBindKey ? thisBinding[func] : func;
+
+        if (argPos) {
+          args = reorder(args, argPos);
+        }
+        if (isAry && ary < args.length) {
+          args.length = ary;
+        }
+        if (this && this !== root && this instanceof wrapper) {
+          fn = Ctor || createCtorWrapper(func);
+        }
+        return fn.apply(thisBinding, args);
+      }
+      return wrapper;
+    }
+
+    /**
+     * Creates the padding required for `string` based on the given `length`.
+     * The `chars` string is truncated if the number of characters exceeds `length`.
+     *
+     * @private
+     * @param {string} string The string to create padding for.
+     * @param {number} [length=0] The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the pad for `string`.
+     */
+    function createPadding(string, length, chars) {
+      var strLength = string.length;
+      length = +length;
+
+      if (strLength >= length || !nativeIsFinite(length)) {
+        return '';
+      }
+      var padLength = length - strLength;
+      chars = chars == null ? ' ' : (chars + '');
+      return repeat(chars, nativeCeil(padLength / chars.length)).slice(0, padLength);
+    }
+
+    /**
+     * Creates a function that wraps `func` and invokes it with the optional `this`
+     * binding of `thisArg` and the `partials` prepended to those provided to
+     * the wrapper.
+     *
+     * @private
+     * @param {Function} func The function to partially apply arguments to.
+     * @param {number} bitmask The bitmask of flags. See `createWrapper` for more details.
+     * @param {*} thisArg The `this` binding of `func`.
+     * @param {Array} partials The arguments to prepend to those provided to the new function.
+     * @returns {Function} Returns the new bound function.
+     */
+    function createPartialWrapper(func, bitmask, thisArg, partials) {
+      var isBind = bitmask & BIND_FLAG,
+          Ctor = createCtorWrapper(func);
+
+      function wrapper() {
+        // Avoid `arguments` object use disqualifying optimizations by
+        // converting it to an array before providing it `func`.
+        var argsIndex = -1,
+            argsLength = arguments.length,
+            leftIndex = -1,
+            leftLength = partials.length,
+            args = Array(leftLength + argsLength);
+
+        while (++leftIndex < leftLength) {
+          args[leftIndex] = partials[leftIndex];
+        }
+        while (argsLength--) {
+          args[leftIndex++] = arguments[++argsIndex];
+        }
+        var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
+        return fn.apply(isBind ? thisArg : this, args);
+      }
+      return wrapper;
+    }
+
+    /**
+     * Creates a `_.ceil`, `_.floor`, or `_.round` function.
+     *
+     * @private
+     * @param {string} methodName The name of the `Math` method to use when rounding.
+     * @returns {Function} Returns the new round function.
+     */
+    function createRound(methodName) {
+      var func = Math[methodName];
+      return function(number, precision) {
+        precision = precision === undefined ? 0 : (+precision || 0);
+        if (precision) {
+          precision = pow(10, precision);
+          return func(number * precision) / precision;
+        }
+        return func(number);
+      };
+    }
+
+    /**
+     * Creates a `_.sortedIndex` or `_.sortedLastIndex` function.
+     *
+     * @private
+     * @param {boolean} [retHighest] Specify returning the highest qualified index.
+     * @returns {Function} Returns the new index function.
+     */
+    function createSortedIndex(retHighest) {
+      return function(array, value, iteratee, thisArg) {
+        var callback = getCallback(iteratee);
+        return (iteratee == null && callback === baseCallback)
+          ? binaryIndex(array, value, retHighest)
+          : binaryIndexBy(array, value, callback(iteratee, thisArg, 1), retHighest);
+      };
+    }
+
+    /**
+     * Creates a function that either curries or invokes `func` with optional
+     * `this` binding and partially applied arguments.
+     *
+     * @private
+     * @param {Function|string} func The function or method name to reference.
+     * @param {number} bitmask The bitmask of flags.
      *  The bitmask may be composed of the following flags:
-     *  1 - `_.bind`
-     *  2 - `_.bindKey`
-     *  4 - `_.curry`
-     *  8 - `_.curry` (bound)
-     *  16 - `_.partial`
-     *  32 - `_.partialRight`
-     * @param {Array} [partialArgs] An array of arguments to prepend to those
-     *  provided to the new function.
-     * @param {Array} [partialRightArgs] An array of arguments to append to those
-     *  provided to the new function.
+     *     1 - `_.bind`
+     *     2 - `_.bindKey`
+     *     4 - `_.curry` or `_.curryRight` of a bound function
+     *     8 - `_.curry`
+     *    16 - `_.curryRight`
+     *    32 - `_.partial`
+     *    64 - `_.partialRight`
+     *   128 - `_.rearg`
+     *   256 - `_.ary`
      * @param {*} [thisArg] The `this` binding of `func`.
+     * @param {Array} [partials] The arguments to be partially applied.
+     * @param {Array} [holders] The `partials` placeholder indexes.
+     * @param {Array} [argPos] The argument positions of the new function.
+     * @param {number} [ary] The arity cap of `func`.
      * @param {number} [arity] The arity of `func`.
-     * @returns {Function} Returns the new function.
-     */
-    function createWrapper(func, bitmask, partialArgs, partialRightArgs, thisArg, arity) {
-      var isBind = bitmask & 1,
-          isBindKey = bitmask & 2,
-          isCurry = bitmask & 4,
-          isCurryBound = bitmask & 8,
-          isPartial = bitmask & 16,
-          isPartialRight = bitmask & 32;
-
-      if (!isBindKey && !isFunction(func)) {
-        throw new TypeError;
-      }
-      if (isPartial && !partialArgs.length) {
-        bitmask &= ~16;
-        isPartial = partialArgs = false;
-      }
-      if (isPartialRight && !partialRightArgs.length) {
-        bitmask &= ~32;
-        isPartialRight = partialRightArgs = false;
-      }
-      var bindData = func && func.__bindData__;
-      if (bindData && bindData !== true) {
-        // clone `bindData`
-        bindData = slice(bindData);
-        if (bindData[2]) {
-          bindData[2] = slice(bindData[2]);
-        }
-        if (bindData[3]) {
-          bindData[3] = slice(bindData[3]);
-        }
-        // set `thisBinding` is not previously bound
-        if (isBind && !(bindData[1] & 1)) {
-          bindData[4] = thisArg;
-        }
-        // set if previously bound but not currently (subsequent curried functions)
-        if (!isBind && bindData[1] & 1) {
-          bitmask |= 8;
-        }
-        // set curried arity if not yet set
-        if (isCurry && !(bindData[1] & 4)) {
-          bindData[5] = arity;
-        }
-        // append partial left arguments
-        if (isPartial) {
-          push.apply(bindData[2] || (bindData[2] = []), partialArgs);
-        }
-        // append partial right arguments
-        if (isPartialRight) {
-          unshift.apply(bindData[3] || (bindData[3] = []), partialRightArgs);
-        }
-        // merge flags
-        bindData[1] |= bitmask;
-        return createWrapper.apply(null, bindData);
-      }
-      // fast path for `_.bind`
-      var creater = (bitmask == 1 || bitmask === 17) ? baseBind : baseCreateWrapper;
-      return creater([func, bitmask, partialArgs, partialRightArgs, thisArg, arity]);
-    }
-
-    /**
-     * Used by `escape` to convert characters to HTML entities.
-     *
-     * @private
-     * @param {string} match The matched character to escape.
-     * @returns {string} Returns the escaped character.
-     */
-    function escapeHtmlChar(match) {
-      return htmlEscapes[match];
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createWrapper(func, bitmask, thisArg, partials, holders, argPos, ary, arity) {
+      var isBindKey = bitmask & BIND_KEY_FLAG;
+      if (!isBindKey && typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      var length = partials ? partials.length : 0;
+      if (!length) {
+        bitmask &= ~(PARTIAL_FLAG | PARTIAL_RIGHT_FLAG);
+        partials = holders = undefined;
+      }
+      length -= (holders ? holders.length : 0);
+      if (bitmask & PARTIAL_RIGHT_FLAG) {
+        var partialsRight = partials,
+            holdersRight = holders;
+
+        partials = holders = undefined;
+      }
+      var data = isBindKey ? undefined : getData(func),
+          newData = [func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity];
+
+      if (data) {
+        mergeData(newData, data);
+        bitmask = newData[1];
+        arity = newData[9];
+      }
+      newData[9] = arity == null
+        ? (isBindKey ? 0 : func.length)
+        : (nativeMax(arity - length, 0) || 0);
+
+      if (bitmask == BIND_FLAG) {
+        var result = createBindWrapper(newData[0], newData[2]);
+      } else if ((bitmask == PARTIAL_FLAG || bitmask == (BIND_FLAG | PARTIAL_FLAG)) && !newData[4].length) {
+        result = createPartialWrapper.apply(undefined, newData);
+      } else {
+        result = createHybridWrapper.apply(undefined, newData);
+      }
+      var setter = data ? baseSetData : setData;
+      return setter(result, newData);
+    }
+
+    /**
+     * A specialized version of `baseIsEqualDeep` for arrays with support for
+     * partial deep comparisons.
+     *
+     * @private
+     * @param {Array} array The array to compare.
+     * @param {Array} other The other array to compare.
+     * @param {Function} equalFunc The function to determine equivalents of values.
+     * @param {Function} [customizer] The function to customize comparing arrays.
+     * @param {boolean} [isLoose] Specify performing partial comparisons.
+     * @param {Array} [stackA] Tracks traversed `value` objects.
+     * @param {Array} [stackB] Tracks traversed `other` objects.
+     * @returns {boolean} Returns `true` if the arrays are equivalent, else `false`.
+     */
+    function equalArrays(array, other, equalFunc, customizer, isLoose, stackA, stackB) {
+      var index = -1,
+          arrLength = array.length,
+          othLength = other.length;
+
+      if (arrLength != othLength && !(isLoose && othLength > arrLength)) {
+        return false;
+      }
+      // Ignore non-index properties.
+      while (++index < arrLength) {
+        var arrValue = array[index],
+            othValue = other[index],
+            result = customizer ? customizer(isLoose ? othValue : arrValue, isLoose ? arrValue : othValue, index) : undefined;
+
+        if (result !== undefined) {
+          if (result) {
+            continue;
+          }
+          return false;
+        }
+        // Recursively compare arrays (susceptible to call stack limits).
+        if (isLoose) {
+          if (!arraySome(other, function(othValue) {
+                return arrValue === othValue || equalFunc(arrValue, othValue, customizer, isLoose, stackA, stackB);
+              })) {
+            return false;
+          }
+        } else if (!(arrValue === othValue || equalFunc(arrValue, othValue, customizer, isLoose, stackA, stackB))) {
+          return false;
+        }
+      }
+      return true;
+    }
+
+    /**
+     * A specialized version of `baseIsEqualDeep` for comparing objects of
+     * the same `toStringTag`.
+     *
+     * **Note:** This function only supports comparing values with tags of
+     * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
+     *
+     * @private
+     * @param {Object} object The object to compare.
+     * @param {Object} other The other object to compare.
+     * @param {string} tag The `toStringTag` of the objects to compare.
+     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
+     */
+    function equalByTag(object, other, tag) {
+      switch (tag) {
+        case boolTag:
+        case dateTag:
+          // Coerce dates and booleans to numbers, dates to milliseconds and booleans
+          // to `1` or `0` treating invalid dates coerced to `NaN` as not equal.
+          return +object == +other;
+
+        case errorTag:
+          return object.name == other.name && object.message == other.message;
+
+        case numberTag:
+          // Treat `NaN` vs. `NaN` as equal.
+          return (object != +object)
+            ? other != +other
+            : object == +other;
+
+        case regexpTag:
+        case stringTag:
+          // Coerce regexes to strings and treat strings primitives and string
+          // objects as equal. See https://es5.github.io/#x15.10.6.4 for more details.
+          return object == (other + '');
+      }
+      return false;
+    }
+
+    /**
+     * A specialized version of `baseIsEqualDeep` for objects with support for
+     * partial deep comparisons.
+     *
+     * @private
+     * @param {Object} object The object to compare.
+     * @param {Object} other The other object to compare.
+     * @param {Function} equalFunc The function to determine equivalents of values.
+     * @param {Function} [customizer] The function to customize comparing values.
+     * @param {boolean} [isLoose] Specify performing partial comparisons.
+     * @param {Array} [stackA] Tracks traversed `value` objects.
+     * @param {Array} [stackB] Tracks traversed `other` objects.
+     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
+     */
+    function equalObjects(object, other, equalFunc, customizer, isLoose, stackA, stackB) {
+      var objProps = keys(object),
+          objLength = objProps.length,
+          othProps = keys(other),
+          othLength = othProps.length;
+
+      if (objLength != othLength && !isLoose) {
+        return false;
+      }
+      var index = objLength;
+      while (index--) {
+        var key = objProps[index];
+        if (!(isLoose ? key in other : hasOwnProperty.call(other, key))) {
+          return false;
+        }
+      }
+      var skipCtor = isLoose;
+      while (++index < objLength) {
+        key = objProps[index];
+        var objValue = object[key],
+            othValue = other[key],
+            result = customizer ? customizer(isLoose ? othValue : objValue, isLoose? objValue : othValue, key) : undefined;
+
+        // Recursively compare objects (susceptible to call stack limits).
+        if (!(result === undefined ? equalFunc(objValue, othValue, customizer, isLoose, stackA, stackB) : result)) {
+          return false;
+        }
+        skipCtor || (skipCtor = key == 'constructor');
+      }
+      if (!skipCtor) {
+        var objCtor = object.constructor,
+            othCtor = other.constructor;
+
+        // Non `Object` object instances with different constructors are not equal.
+        if (objCtor != othCtor &&
+            ('constructor' in object && 'constructor' in other) &&
+            !(typeof objCtor == 'function' && objCtor instanceof objCtor &&
+              typeof othCtor == 'function' && othCtor instanceof othCtor)) {
+          return false;
+        }
+      }
+      return true;
+    }
+
+    /**
+     * Gets the appropriate "callback" function. If the `_.callback` method is
+     * customized this function returns the custom method, otherwise it returns
+     * the `baseCallback` function. If arguments are provided the chosen function
+     * is invoked with them and its result is returned.
+     *
+     * @private
+     * @returns {Function} Returns the chosen function or its result.
+     */
+    function getCallback(func, thisArg, argCount) {
+      var result = lodash.callback || callback;
+      result = result === callback ? baseCallback : result;
+      return argCount ? result(func, thisArg, argCount) : result;
+    }
+
+    /**
+     * Gets metadata for `func`.
+     *
+     * @private
+     * @param {Function} func The function to query.
+     * @returns {*} Returns the metadata for `func`.
+     */
+    var getData = !metaMap ? noop : function(func) {
+      return metaMap.get(func);
+    };
+
+    /**
+     * Gets the name of `func`.
+     *
+     * @private
+     * @param {Function} func The function to query.
+     * @returns {string} Returns the function name.
+     */
+    function getFuncName(func) {
+      var result = (func.name + ''),
+          array = realNames[result],
+          length = array ? array.length : 0;
+
+      while (length--) {
+        var data = array[length],
+            otherFunc = data.func;
+        if (otherFunc == null || otherFunc == func) {
+          return data.name;
+        }
+      }
+      return result;
     }
 
     /**
      * Gets the appropriate "indexOf" function. If the `_.indexOf` method is
-     * customized, this method returns the custom method, otherwise it returns
-     * the `baseIndexOf` function.
-     *
-     * @private
-     * @returns {Function} Returns the "indexOf" function.
-     */
-    function getIndexOf() {
-      var result = (result = lodash.indexOf) === indexOf ? baseIndexOf : result;
+     * customized this function returns the custom method, otherwise it returns
+     * the `baseIndexOf` function. If arguments are provided the chosen function
+     * is invoked with them and its result is returned.
+     *
+     * @private
+     * @returns {Function|number} Returns the chosen function or its result.
+     */
+    function getIndexOf(collection, target, fromIndex) {
+      var result = lodash.indexOf || indexOf;
+      result = result === indexOf ? baseIndexOf : result;
+      return collection ? result(collection, target, fromIndex) : result;
+    }
+
+    /**
+     * Gets the "length" property value of `object`.
+     *
+     * **Note:** This function is used to avoid a [JIT bug](https://bugs.webkit.org/show_bug.cgi?id=142792)
+     * that affects Safari on at least iOS 8.1-8.3 ARM64.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {*} Returns the "length" value.
+     */
+    var getLength = baseProperty('length');
+
+    /**
+     * Gets the propery names, values, and compare flags of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the match data of `object`.
+     */
+    function getMatchData(object) {
+      var result = pairs(object),
+          length = result.length;
+
+      while (length--) {
+        result[length][2] = isStrictComparable(result[length][1]);
+      }
       return result;
     }
 
     /**
-     * Checks if `value` is a native function.
+     * Gets the native function at `key` of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {string} key The key of the method to get.
+     * @returns {*} Returns the function if it's native, else `undefined`.
+     */
+    function getNative(object, key) {
+      var value = object == null ? undefined : object[key];
+      return isNative(value) ? value : undefined;
+    }
+
+    /**
+     * Gets the view, applying any `transforms` to the `start` and `end` positions.
+     *
+     * @private
+     * @param {number} start The start of the view.
+     * @param {number} end The end of the view.
+     * @param {Array} transforms The transformations to apply to the view.
+     * @returns {Object} Returns an object containing the `start` and `end`
+     *  positions of the view.
+     */
+    function getView(start, end, transforms) {
+      var index = -1,
+          length = transforms.length;
+
+      while (++index < length) {
+        var data = transforms[index],
+            size = data.size;
+
+        switch (data.type) {
+          case 'drop':      start += size; break;
+          case 'dropRight': end -= size; break;
+          case 'take':      end = nativeMin(end, start + size); break;
+          case 'takeRight': start = nativeMax(start, end - size); break;
+        }
+      }
+      return { 'start': start, 'end': end };
+    }
+
+    /**
+     * Initializes an array clone.
+     *
+     * @private
+     * @param {Array} array The array to clone.
+     * @returns {Array} Returns the initialized clone.
+     */
+    function initCloneArray(array) {
+      var length = array.length,
+          result = new array.constructor(length);
+
+      // Add array properties assigned by `RegExp#exec`.
+      if (length && typeof array[0] == 'string' && hasOwnProperty.call(array, 'index')) {
+        result.index = array.index;
+        result.input = array.input;
+      }
+      return result;
+    }
+
+    /**
+     * Initializes an object clone.
+     *
+     * @private
+     * @param {Object} object The object to clone.
+     * @returns {Object} Returns the initialized clone.
+     */
+    function initCloneObject(object) {
+      var Ctor = object.constructor;
+      if (!(typeof Ctor == 'function' && Ctor instanceof Ctor)) {
+        Ctor = Object;
+      }
+      return new Ctor;
+    }
+
+    /**
+     * Initializes an object clone based on its `toStringTag`.
+     *
+     * **Note:** This function only supports cloning values with tags of
+     * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
+     *
+     * @private
+     * @param {Object} object The object to clone.
+     * @param {string} tag The `toStringTag` of the object to clone.
+     * @param {boolean} [isDeep] Specify a deep clone.
+     * @returns {Object} Returns the initialized clone.
+     */
+    function initCloneByTag(object, tag, isDeep) {
+      var Ctor = object.constructor;
+      switch (tag) {
+        case arrayBufferTag:
+          return bufferClone(object);
+
+        case boolTag:
+        case dateTag:
+          return new Ctor(+object);
+
+        case float32Tag: case float64Tag:
+        case int8Tag: case int16Tag: case int32Tag:
+        case uint8Tag: case uint8ClampedTag: case uint16Tag: case uint32Tag:
+          var buffer = object.buffer;
+          return new Ctor(isDeep ? bufferClone(buffer) : buffer, object.byteOffset, object.length);
+
+        case numberTag:
+        case stringTag:
+          return new Ctor(object);
+
+        case regexpTag:
+          var result = new Ctor(object.source, reFlags.exec(object));
+          result.lastIndex = object.lastIndex;
+      }
+      return result;
+    }
+
+    /**
+     * Invokes the method at `path` on `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the method to invoke.
+     * @param {Array} args The arguments to invoke the method with.
+     * @returns {*} Returns the result of the invoked method.
+     */
+    function invokePath(object, path, args) {
+      if (object != null && !isKey(path, object)) {
+        path = toPath(path);
+        object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+        path = last(path);
+      }
+      var func = object == null ? object : object[path];
+      return func == null ? undefined : func.apply(object, args);
+    }
+
+    /**
+     * Checks if `value` is array-like.
      *
      * @private
      * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a native function, else `false`.
-     */
-    function isNative(value) {
-      return typeof value == 'function' && reNative.test(value);
-    }
-
-    /**
-     * Sets `this` binding data on a given function.
-     *
-     * @private
-     * @param {Function} func The function to set data on.
-     * @param {Array} value The data array to set.
-     */
-    var setBindData = !defineProperty ? noop : function(func, value) {
-      descriptor.value = value;
-      defineProperty(func, '__bindData__', descriptor);
-      descriptor.value = null;
-    };
-
-    /**
-     * A fallback implementation of `isPlainObject` which checks if a given value
-     * is an object created by the `Object` constructor, assuming objects created
-     * by the `Object` constructor have no inherited enumerable properties and that
-     * there are no `Object.prototype` extensions.
+     * @returns {boolean} Returns `true` if `value` is array-like, else `false`.
+     */
+    function isArrayLike(value) {
+      return value != null && isLength(getLength(value));
+    }
+
+    /**
+     * Checks if `value` is a valid array-like index.
      *
      * @private
      * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
-     */
-    function shimIsPlainObject(value) {
-      var ctor,
-          result;
-
-      // avoid non Object objects, `arguments` objects, and DOM elements
-      if (!(value && toString.call(value) == objectClass) ||
-          (ctor = value.constructor, isFunction(ctor) && !(ctor instanceof ctor))) {
-        return false;
-      }
-      // In most environments an object's own properties are iterated before
-      // its inherited properties. If the last iterated property is an object's
-      // own property then there are no inherited enumerable properties.
-      forIn(value, function(value, key) {
-        result = key;
-      });
-      return typeof result == 'undefined' || hasOwnProperty.call(value, result);
-    }
-
-    /**
-     * Used by `unescape` to convert HTML entities to characters.
-     *
-     * @private
-     * @param {string} match The matched character to unescape.
-     * @returns {string} Returns the unescaped character.
-     */
-    function unescapeHtmlChar(match) {
-      return htmlUnescapes[match];
-    }
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Checks if `value` is an `arguments` object.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is an `arguments` object, else `false`.
-     * @example
-     *
-     * (function() { return _.isArguments(arguments); })(1, 2, 3);
-     * // => true
-     *
-     * _.isArguments([1, 2, 3]);
-     * // => false
-     */
-    function isArguments(value) {
-      return value && typeof value == 'object' && typeof value.length == 'number' &&
-        toString.call(value) == argsClass || false;
-    }
-
-    /**
-     * Checks if `value` is an array.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is an array, else `false`.
-     * @example
-     *
-     * (function() { return _.isArray(arguments); })();
-     * // => false
-     *
-     * _.isArray([1, 2, 3]);
-     * // => true
-     */
-    var isArray = nativeIsArray || function(value) {
-      return value && typeof value == 'object' && typeof value.length == 'number' &&
-        toString.call(value) == arrayClass || false;
-    };
-
-    /**
-     * A fallback implementation of `Object.keys` which produces an array of the
-     * given object's own enumerable property names.
-     *
-     * @private
-     * @type Function
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property names.
-     */
-    var shimKeys = function(object) {
-      var index, iterable = object, result = [];
-      if (!iterable) return result;
-      if (!(objectTypes[typeof object])) return result;
-        for (index in iterable) {
-          if (hasOwnProperty.call(iterable, index)) {
-            result.push(index);
-          }
-        }
-      return result
-    };
-
-    /**
-     * Creates an array composed of the own enumerable property names of an object.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property names.
-     * @example
-     *
-     * _.keys({ 'one': 1, 'two': 2, 'three': 3 });
-     * // => ['one', 'two', 'three'] (property order is not guaranteed across environments)
-     */
-    var keys = !nativeKeys ? shimKeys : function(object) {
+     * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
+     * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
+     */
+    function isIndex(value, length) {
+      value = (typeof value == 'number' || reIsUint.test(value)) ? +value : -1;
+      length = length == null ? MAX_SAFE_INTEGER : length;
+      return value > -1 && value % 1 == 0 && value < length;
+    }
+
+    /**
+     * Checks if the provided arguments are from an iteratee call.
+     *
+     * @private
+     * @param {*} value The potential iteratee value argument.
+     * @param {*} index The potential iteratee index or key argument.
+     * @param {*} object The potential iteratee object argument.
+     * @returns {boolean} Returns `true` if the arguments are from an iteratee call, else `false`.
+     */
+    function isIterateeCall(value, index, object) {
       if (!isObject(object)) {
-        return [];
-      }
-      return nativeKeys(object);
-    };
-
-    /**
-     * Used to convert characters to HTML entities:
-     *
-     * Though the `>` character is escaped for symmetry, characters like `>` and `/`
-     * don't require escaping in HTML and have no special meaning unless they're part
-     * of a tag or an unquoted attribute value.
-     * http://mathiasbynens.be/notes/ambiguous-ampersands (under "semi-related fun fact")
-     */
-    var htmlEscapes = {
-      '&': '&amp;',
-      '<': '&lt;',
-      '>': '&gt;',
-      '"': '&quot;',
-      "'": '&#39;'
-    };
-
-    /** Used to convert HTML entities to characters */
-    var htmlUnescapes = invert(htmlEscapes);
-
-    /** Used to match HTML entities and HTML characters */
-    var reEscapedHtml = RegExp('(' + keys(htmlUnescapes).join('|') + ')', 'g'),
-        reUnescapedHtml = RegExp('[' + keys(htmlEscapes).join('') + ']', 'g');
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Assigns own enumerable properties of source object(s) to the destination
-     * object. Subsequent sources will overwrite property assignments of previous
-     * sources. If a callback is provided it will be executed to produce the
-     * assigned values. The callback is bound to `thisArg` and invoked with two
-     * arguments; (objectValue, sourceValue).
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @alias extend
-     * @category Objects
-     * @param {Object} object The destination object.
-     * @param {...Object} [source] The source objects.
-     * @param {Function} [callback] The function to customize assigning values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns the destination object.
-     * @example
-     *
-     * _.assign({ 'name': 'fred' }, { 'employer': 'slate' });
-     * // => { 'name': 'fred', 'employer': 'slate' }
-     *
-     * var defaults = _.partialRight(_.assign, function(a, b) {
-     *   return typeof a == 'undefined' ? b : a;
-     * });
-     *
-     * var object = { 'name': 'barney' };
-     * defaults(object, { 'name': 'fred', 'employer': 'slate' });
-     * // => { 'name': 'barney', 'employer': 'slate' }
-     */
-    var assign = function(object, source, guard) {
-      var index, iterable = object, result = iterable;
-      if (!iterable) return result;
-      var args = arguments,
-          argsIndex = 0,
-          argsLength = typeof guard == 'number' ? 2 : args.length;
-      if (argsLength > 3 && typeof args[argsLength - 2] == 'function') {
-        var callback = baseCreateCallback(args[--argsLength - 1], args[argsLength--], 2);
-      } else if (argsLength > 2 && typeof args[argsLength - 1] == 'function') {
-        callback = args[--argsLength];
-      }
-      while (++argsIndex < argsLength) {
-        iterable = args[argsIndex];
-        if (iterable && objectTypes[typeof iterable]) {
-        var ownIndex = -1,
-            ownProps = objectTypes[typeof iterable] && keys(iterable),
-            length = ownProps ? ownProps.length : 0;
-
-        while (++ownIndex < length) {
-          index = ownProps[ownIndex];
-          result[index] = callback ? callback(result[index], iterable[index]) : iterable[index];
-        }
-        }
-      }
-      return result
-    };
-
-    /**
-     * Creates a clone of `value`. If `isDeep` is `true` nested objects will also
-     * be cloned, otherwise they will be assigned by reference. If a callback
-     * is provided it will be executed to produce the cloned values. If the
-     * callback returns `undefined` cloning will be handled by the method instead.
-     * The callback is bound to `thisArg` and invoked with one argument; (value).
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to clone.
-     * @param {boolean} [isDeep=false] Specify a deep clone.
-     * @param {Function} [callback] The function to customize cloning values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the cloned value.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
-     *
-     * var shallow = _.clone(characters);
-     * shallow[0] === characters[0];
-     * // => true
-     *
-     * var deep = _.clone(characters, true);
-     * deep[0] === characters[0];
-     * // => false
-     *
-     * _.mixin({
-     *   'clone': _.partialRight(_.clone, function(value) {
-     *     return _.isElement(value) ? value.cloneNode(false) : undefined;
-     *   })
-     * });
-     *
-     * var clone = _.clone(document.body);
-     * clone.childNodes.length;
-     * // => 0
-     */
-    function clone(value, isDeep, callback, thisArg) {
-      // allows working with "Collections" methods without using their `index`
-      // and `collection` arguments for `isDeep` and `callback`
-      if (typeof isDeep != 'boolean' && isDeep != null) {
-        thisArg = callback;
-        callback = isDeep;
-        isDeep = false;
-      }
-      return baseClone(value, isDeep, typeof callback == 'function' && baseCreateCallback(callback, thisArg, 1));
-    }
-
-    /**
-     * Creates a deep clone of `value`. If a callback is provided it will be
-     * executed to produce the cloned values. If the callback returns `undefined`
-     * cloning will be handled by the method instead. The callback is bound to
-     * `thisArg` and invoked with one argument; (value).
-     *
-     * Note: This method is loosely based on the structured clone algorithm. Functions
-     * and DOM nodes are **not** cloned. The enumerable properties of `arguments` objects and
-     * objects created by constructors other than `Object` are cloned to plain `Object` objects.
-     * See http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to deep clone.
-     * @param {Function} [callback] The function to customize cloning values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the deep cloned value.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
-     *
-     * var deep = _.cloneDeep(characters);
-     * deep[0] === characters[0];
-     * // => false
-     *
-     * var view = {
-     *   'label': 'docs',
-     *   'node': element
-     * };
-     *
-     * var clone = _.cloneDeep(view, function(value) {
-     *   return _.isElement(value) ? value.cloneNode(true) : undefined;
-     * });
-     *
-     * clone.node == view.node;
-     * // => false
-     */
-    function cloneDeep(value, callback, thisArg) {
-      return baseClone(value, true, typeof callback == 'function' && baseCreateCallback(callback, thisArg, 1));
-    }
-
-    /**
-     * Creates an object that inherits from the given `prototype` object. If a
-     * `properties` object is provided its own enumerable properties are assigned
-     * to the created object.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} prototype The object to inherit from.
-     * @param {Object} [properties] The properties to assign to the object.
+        return false;
+      }
+      var type = typeof index;
+      if (type == 'number'
+          ? (isArrayLike(object) && isIndex(index, object.length))
+          : (type == 'string' && index in object)) {
+        var other = object[index];
+        return value === value ? (value === other) : (other !== other);
+      }
+      return false;
+    }
+
+    /**
+     * Checks if `value` is a property name and not a property path.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @param {Object} [object] The object to query keys on.
+     * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
+     */
+    function isKey(value, object) {
+      var type = typeof value;
+      if ((type == 'string' && reIsPlainProp.test(value)) || type == 'number') {
+        return true;
+      }
+      if (isArray(value)) {
+        return false;
+      }
+      var result = !reIsDeepProp.test(value);
+      return result || (object != null && value in toObject(object));
+    }
+
+    /**
+     * Checks if `func` has a lazy counterpart.
+     *
+     * @private
+     * @param {Function} func The function to check.
+     * @returns {boolean} Returns `true` if `func` has a lazy counterpart, else `false`.
+     */
+    function isLaziable(func) {
+      var funcName = getFuncName(func),
+          other = lodash[funcName];
+
+      if (typeof other != 'function' || !(funcName in LazyWrapper.prototype)) {
+        return false;
+      }
+      if (func === other) {
+        return true;
+      }
+      var data = getData(other);
+      return !!data && func === data[0];
+    }
+
+    /**
+     * Checks if `value` is a valid array-like length.
+     *
+     * **Note:** This function is based on [`ToLength`](http://ecma-international.org/ecma-262/6.0/#sec-tolength).
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a valid length, else `false`.
+     */
+    function isLength(value) {
+      return typeof value == 'number' && value > -1 && value % 1 == 0 && value <= MAX_SAFE_INTEGER;
+    }
+
+    /**
+     * Checks if `value` is suitable for strict equality comparisons, i.e. `===`.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` if suitable for strict
+     *  equality comparisons, else `false`.
+     */
+    function isStrictComparable(value) {
+      return value === value && !isObject(value);
+    }
+
+    /**
+     * Merges the function metadata of `source` into `data`.
+     *
+     * Merging metadata reduces the number of wrappers required to invoke a function.
+     * This is possible because methods like `_.bind`, `_.curry`, and `_.partial`
+     * may be applied regardless of execution order. Methods like `_.ary` and `_.rearg`
+     * augment function arguments, making the order in which they are executed important,
+     * preventing the merging of metadata. However, we make an exception for a safe
+     * common case where curried functions have `_.ary` and or `_.rearg` applied.
+     *
+     * @private
+     * @param {Array} data The destination metadata.
+     * @param {Array} source The source metadata.
+     * @returns {Array} Returns `data`.
+     */
+    function mergeData(data, source) {
+      var bitmask = data[1],
+          srcBitmask = source[1],
+          newBitmask = bitmask | srcBitmask,
+          isCommon = newBitmask < ARY_FLAG;
+
+      var isCombo =
+        (srcBitmask == ARY_FLAG && bitmask == CURRY_FLAG) ||
+        (srcBitmask == ARY_FLAG && bitmask == REARG_FLAG && data[7].length <= source[8]) ||
+        (srcBitmask == (ARY_FLAG | REARG_FLAG) && bitmask == CURRY_FLAG);
+
+      // Exit early if metadata can't be merged.
+      if (!(isCommon || isCombo)) {
+        return data;
+      }
+      // Use source `thisArg` if available.
+      if (srcBitmask & BIND_FLAG) {
+        data[2] = source[2];
+        // Set when currying a bound function.
+        newBitmask |= (bitmask & BIND_FLAG) ? 0 : CURRY_BOUND_FLAG;
+      }
+      // Compose partial arguments.
+      var value = source[3];
+      if (value) {
+        var partials = data[3];
+        data[3] = partials ? composeArgs(partials, value, source[4]) : arrayCopy(value);
+        data[4] = partials ? replaceHolders(data[3], PLACEHOLDER) : arrayCopy(source[4]);
+      }
+      // Compose partial right arguments.
+      value = source[5];
+      if (value) {
+        partials = data[5];
+        data[5] = partials ? composeArgsRight(partials, value, source[6]) : arrayCopy(value);
+        data[6] = partials ? replaceHolders(data[5], PLACEHOLDER) : arrayCopy(source[6]);
+      }
+      // Use source `argPos` if available.
+      value = source[7];
+      if (value) {
+        data[7] = arrayCopy(value);
+      }
+      // Use source `ary` if it's smaller.
+      if (srcBitmask & ARY_FLAG) {
+        data[8] = data[8] == null ? source[8] : nativeMin(data[8], source[8]);
+      }
+      // Use source `arity` if one is not provided.
+      if (data[9] == null) {
+        data[9] = source[9];
+      }
+      // Use source `func` and merge bitmasks.
+      data[0] = source[0];
+      data[1] = newBitmask;
+
+      return data;
+    }
+
+    /**
+     * Used by `_.defaultsDeep` to customize its `_.merge` use.
+     *
+     * @private
+     * @param {*} objectValue The destination object property value.
+     * @param {*} sourceValue The source object property value.
+     * @returns {*} Returns the value to assign to the destination object.
+     */
+    function mergeDefaults(objectValue, sourceValue) {
+      return objectValue === undefined ? sourceValue : merge(objectValue, sourceValue, mergeDefaults);
+    }
+
+    /**
+     * A specialized version of `_.pick` which picks `object` properties specified
+     * by `props`.
+     *
+     * @private
+     * @param {Object} object The source object.
+     * @param {string[]} props The property names to pick.
      * @returns {Object} Returns the new object.
-     * @example
-     *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
-     *
-     * function Circle() {
-     *   Shape.call(this);
-     * }
-     *
-     * Circle.prototype = _.create(Shape.prototype, { 'constructor': Circle });
-     *
-     * var circle = new Circle;
-     * circle instanceof Circle;
-     * // => true
-     *
-     * circle instanceof Shape;
-     * // => true
-     */
-    function create(prototype, properties) {
-      var result = baseCreate(prototype);
-      return properties ? assign(result, properties) : result;
-    }
-
-    /**
-     * Assigns own enumerable properties of source object(s) to the destination
-     * object for all destination properties that resolve to `undefined`. Once a
-     * property is set, additional defaults of the same property will be ignored.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {Object} object The destination object.
-     * @param {...Object} [source] The source objects.
-     * @param- {Object} [guard] Allows working with `_.reduce` without using its
-     *  `key` and `object` arguments as sources.
-     * @returns {Object} Returns the destination object.
-     * @example
-     *
-     * var object = { 'name': 'barney' };
-     * _.defaults(object, { 'name': 'fred', 'employer': 'slate' });
-     * // => { 'name': 'barney', 'employer': 'slate' }
-     */
-    var defaults = function(object, source, guard) {
-      var index, iterable = object, result = iterable;
-      if (!iterable) return result;
-      var args = arguments,
-          argsIndex = 0,
-          argsLength = typeof guard == 'number' ? 2 : args.length;
-      while (++argsIndex < argsLength) {
-        iterable = args[argsIndex];
-        if (iterable && objectTypes[typeof iterable]) {
-        var ownIndex = -1,
-            ownProps = objectTypes[typeof iterable] && keys(iterable),
-            length = ownProps ? ownProps.length : 0;
-
-        while (++ownIndex < length) {
-          index = ownProps[ownIndex];
-          if (typeof result[index] == 'undefined') result[index] = iterable[index];
-        }
-        }
-      }
-      return result
-    };
-
-    /**
-     * This method is like `_.findIndex` except that it returns the key of the
-     * first element that passes the callback check, instead of the element itself.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to search.
-     * @param {Function|Object|string} [callback=identity] The function called per
-     *  iteration. If a property name or object is provided it will be used to
-     *  create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {string|undefined} Returns the key of the found element, else `undefined`.
-     * @example
-     *
-     * var characters = {
-     *   'barney': {  'age': 36, 'blocked': false },
-     *   'fred': {    'age': 40, 'blocked': true },
-     *   'pebbles': { 'age': 1,  'blocked': false }
-     * };
-     *
-     * _.findKey(characters, function(chr) {
-     *   return chr.age < 40;
-     * });
-     * // => 'barney' (property order is not guaranteed across environments)
-     *
-     * // using "_.where" callback shorthand
-     * _.findKey(characters, { 'age': 1 });
-     * // => 'pebbles'
-     *
-     * // using "_.pluck" callback shorthand
-     * _.findKey(characters, 'blocked');
-     * // => 'fred'
-     */
-    function findKey(object, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      forOwn(object, function(value, key, object) {
-        if (callback(value, key, object)) {
-          result = key;
-          return false;
-        }
-      });
-      return result;
-    }
-
-    /**
-     * This method is like `_.findKey` except that it iterates over elements
-     * of a `collection` in the opposite order.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to search.
-     * @param {Function|Object|string} [callback=identity] The function called per
-     *  iteration. If a property name or object is provided it will be used to
-     *  create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {string|undefined} Returns the key of the found element, else `undefined`.
-     * @example
-     *
-     * var characters = {
-     *   'barney': {  'age': 36, 'blocked': true },
-     *   'fred': {    'age': 40, 'blocked': false },
-     *   'pebbles': { 'age': 1,  'blocked': true }
-     * };
-     *
-     * _.findLastKey(characters, function(chr) {
-     *   return chr.age < 40;
-     * });
-     * // => returns `pebbles`, assuming `_.findKey` returns `barney`
-     *
-     * // using "_.where" callback shorthand
-     * _.findLastKey(characters, { 'age': 40 });
-     * // => 'fred'
-     *
-     * // using "_.pluck" callback shorthand
-     * _.findLastKey(characters, 'blocked');
-     * // => 'pebbles'
-     */
-    function findLastKey(object, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      forOwnRight(object, function(value, key, object) {
-        if (callback(value, key, object)) {
-          result = key;
-          return false;
-        }
-      });
-      return result;
-    }
-
-    /**
-     * Iterates over own and inherited enumerable properties of an object,
-     * executing the callback for each property. The callback is bound to `thisArg`
-     * and invoked with three arguments; (value, key, object). Callbacks may exit
-     * iteration early by explicitly returning `false`.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
-     * @example
-     *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
-     *
-     * Shape.prototype.move = function(x, y) {
-     *   this.x += x;
-     *   this.y += y;
-     * };
-     *
-     * _.forIn(new Shape, function(value, key) {
-     *   console.log(key);
-     * });
-     * // => logs 'x', 'y', and 'move' (property order is not guaranteed across environments)
-     */
-    var forIn = function(collection, callback, thisArg) {
-      var index, iterable = collection, result = iterable;
-      if (!iterable) return result;
-      if (!objectTypes[typeof iterable]) return result;
-      callback = callback && typeof thisArg == 'undefined' ? callback : baseCreateCallback(callback, thisArg, 3);
-        for (index in iterable) {
-          if (callback(iterable[index], index, collection) === false) return result;
-        }
-      return result
-    };
-
-    /**
-     * This method is like `_.forIn` except that it iterates over elements
-     * of a `collection` in the opposite order.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
-     * @example
-     *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
-     *
-     * Shape.prototype.move = function(x, y) {
-     *   this.x += x;
-     *   this.y += y;
-     * };
-     *
-     * _.forInRight(new Shape, function(value, key) {
-     *   console.log(key);
-     * });
-     * // => logs 'move', 'y', and 'x' assuming `_.forIn ` logs 'x', 'y', and 'move'
-     */
-    function forInRight(object, callback, thisArg) {
-      var pairs = [];
-
-      forIn(object, function(value, key) {
-        pairs.push(key, value);
-      });
-
-      var length = pairs.length;
-      callback = baseCreateCallback(callback, thisArg, 3);
-      while (length--) {
-        if (callback(pairs[length--], pairs[length], object) === false) {
-          break;
-        }
-      }
-      return object;
-    }
-
-    /**
-     * Iterates over own enumerable properties of an object, executing the callback
-     * for each property. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, key, object). Callbacks may exit iteration early by
-     * explicitly returning `false`.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
-     * @example
-     *
-     * _.forOwn({ '0': 'zero', '1': 'one', 'length': 2 }, function(num, key) {
-     *   console.log(key);
-     * });
-     * // => logs '0', '1', and 'length' (property order is not guaranteed across environments)
-     */
-    var forOwn = function(collection, callback, thisArg) {
-      var index, iterable = collection, result = iterable;
-      if (!iterable) return result;
-      if (!objectTypes[typeof iterable]) return result;
-      callback = callback && typeof thisArg == 'undefined' ? callback : baseCreateCallback(callback, thisArg, 3);
-        var ownIndex = -1,
-            ownProps = objectTypes[typeof iterable] && keys(iterable),
-            length = ownProps ? ownProps.length : 0;
-
-        while (++ownIndex < length) {
-          index = ownProps[ownIndex];
-          if (callback(iterable[index], index, collection) === false) return result;
-        }
-      return result
-    };
-
-    /**
-     * This method is like `_.forOwn` except that it iterates over elements
-     * of a `collection` in the opposite order.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
-     * @example
-     *
-     * _.forOwnRight({ '0': 'zero', '1': 'one', 'length': 2 }, function(num, key) {
-     *   console.log(key);
-     * });
-     * // => logs 'length', '1', and '0' assuming `_.forOwn` logs '0', '1', and 'length'
-     */
-    function forOwnRight(object, callback, thisArg) {
-      var props = keys(object),
-          length = props.length;
-
-      callback = baseCreateCallback(callback, thisArg, 3);
-      while (length--) {
-        var key = props[length];
-        if (callback(object[key], key, object) === false) {
-          break;
-        }
-      }
-      return object;
-    }
-
-    /**
-     * Creates a sorted array of property names of all enumerable properties,
-     * own and inherited, of `object` that have function values.
-     *
-     * @static
-     * @memberOf _
-     * @alias methods
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property names that have function values.
-     * @example
-     *
-     * _.functions(_);
-     * // => ['all', 'any', 'bind', 'bindAll', 'clone', 'compact', 'compose', ...]
-     */
-    function functions(object) {
-      var result = [];
-      forIn(object, function(value, key) {
-        if (isFunction(value)) {
-          result.push(key);
-        }
-      });
-      return result.sort();
-    }
-
-    /**
-     * Checks if the specified property name exists as a direct property of `object`,
-     * instead of an inherited property.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @param {string} key The name of the property to check.
-     * @returns {boolean} Returns `true` if key is a direct property, else `false`.
-     * @example
-     *
-     * _.has({ 'a': 1, 'b': 2, 'c': 3 }, 'b');
-     * // => true
-     */
-    function has(object, key) {
-      return object ? hasOwnProperty.call(object, key) : false;
-    }
-
-    /**
-     * Creates an object composed of the inverted keys and values of the given object.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to invert.
-     * @returns {Object} Returns the created inverted object.
-     * @example
-     *
-     * _.invert({ 'first': 'fred', 'second': 'barney' });
-     * // => { 'fred': 'first', 'barney': 'second' }
-     */
-    function invert(object) {
+     */
+    function pickByArray(object, props) {
+      object = toObject(object);
+
       var index = -1,
-          props = keys(object),
           length = props.length,
           result = {};
 
       while (++index < length) {
         var key = props[index];
-        result[object[key]] = key;
+        if (key in object) {
+          result[key] = object[key];
+        }
       }
       return result;
     }
 
     /**
-     * Checks if `value` is a boolean value.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a boolean value, else `false`.
-     * @example
-     *
-     * _.isBoolean(null);
-     * // => false
-     */
-    function isBoolean(value) {
-      return value === true || value === false ||
-        value && typeof value == 'object' && toString.call(value) == boolClass || false;
-    }
-
-    /**
-     * Checks if `value` is a date.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a date, else `false`.
-     * @example
-     *
-     * _.isDate(new Date);
-     * // => true
-     */
-    function isDate(value) {
-      return value && typeof value == 'object' && toString.call(value) == dateClass || false;
-    }
-
-    /**
-     * Checks if `value` is a DOM element.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a DOM element, else `false`.
-     * @example
-     *
-     * _.isElement(document.body);
-     * // => true
-     */
-    function isElement(value) {
-      return value && value.nodeType === 1 || false;
-    }
-
-    /**
-     * Checks if `value` is empty. Arrays, strings, or `arguments` objects with a
-     * length of `0` and objects with no own enumerable properties are considered
-     * "empty".
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Array|Object|string} value The value to inspect.
-     * @returns {boolean} Returns `true` if the `value` is empty, else `false`.
-     * @example
-     *
-     * _.isEmpty([1, 2, 3]);
-     * // => false
-     *
-     * _.isEmpty({});
-     * // => true
-     *
-     * _.isEmpty('');
-     * // => true
-     */
-    function isEmpty(value) {
-      var result = true;
-      if (!value) {
-        return result;
-      }
-      var className = toString.call(value),
-          length = value.length;
-
-      if ((className == arrayClass || className == stringClass || className == argsClass ) ||
-          (className == objectClass && typeof length == 'number' && isFunction(value.splice))) {
-        return !length;
-      }
-      forOwn(value, function() {
-        return (result = false);
+     * A specialized version of `_.pick` which picks `object` properties `predicate`
+     * returns truthy for.
+     *
+     * @private
+     * @param {Object} object The source object.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {Object} Returns the new object.
+     */
+    function pickByCallback(object, predicate) {
+      var result = {};
+      baseForIn(object, function(value, key, object) {
+        if (predicate(value, key, object)) {
+          result[key] = value;
+        }
+      });
+      return result;
+    }
+
+    /**
+     * Reorder `array` according to the specified indexes where the element at
+     * the first index is assigned as the first element, the element at
+     * the second index is assigned as the second element, and so on.
+     *
+     * @private
+     * @param {Array} array The array to reorder.
+     * @param {Array} indexes The arranged array indexes.
+     * @returns {Array} Returns `array`.
+     */
+    function reorder(array, indexes) {
+      var arrLength = array.length,
+          length = nativeMin(indexes.length, arrLength),
+          oldArray = arrayCopy(array);
+
+      while (length--) {
+        var index = indexes[length];
+        array[length] = isIndex(index, arrLength) ? oldArray[index] : undefined;
+      }
+      return array;
+    }
+
+    /**
+     * Sets metadata for `func`.
+     *
+     * **Note:** If this function becomes hot, i.e. is invoked a lot in a short
+     * period of time, it will trip its breaker and transition to an identity function
+     * to avoid garbage collection pauses in V8. See [V8 issue 2070](https://code.google.com/p/v8/issues/detail?id=2070)
+     * for more details.
+     *
+     * @private
+     * @param {Function} func The function to associate metadata with.
+     * @param {*} data The metadata.
+     * @returns {Function} Returns `func`.
+     */
+    var setData = (function() {
+      var count = 0,
+          lastCalled = 0;
+
+      return function(key, value) {
+        var stamp = now(),
+            remaining = HOT_SPAN - (stamp - lastCalled);
+
+        lastCalled = stamp;
+        if (remaining > 0) {
+          if (++count >= HOT_COUNT) {
+            return key;
+          }
+        } else {
+          count = 0;
+        }
+        return baseSetData(key, value);
+      };
+    }());
+
+    /**
+     * A fallback implementation of `Object.keys` which creates an array of the
+     * own enumerable property names of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names.
+     */
+    function shimKeys(object) {
+      var props = keysIn(object),
+          propsLength = props.length,
+          length = propsLength && object.length;
+
+      var allowIndexes = !!length && isLength(length) &&
+        (isArray(object) || isArguments(object));
+
+      var index = -1,
+          result = [];
+
+      while (++index < propsLength) {
+        var key = props[index];
+        if ((allowIndexes && isIndex(key, length)) || hasOwnProperty.call(object, key)) {
+          result.push(key);
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Converts `value` to an array-like object if it's not one.
+     *
+     * @private
+     * @param {*} value The value to process.
+     * @returns {Array|Object} Returns the array-like object.
+     */
+    function toIterable(value) {
+      if (value == null) {
+        return [];
+      }
+      if (!isArrayLike(value)) {
+        return values(value);
+      }
+      return isObject(value) ? value : Object(value);
+    }
+
+    /**
+     * Converts `value` to an object if it's not one.
+     *
+     * @private
+     * @param {*} value The value to process.
+     * @returns {Object} Returns the object.
+     */
+    function toObject(value) {
+      return isObject(value) ? value : Object(value);
+    }
+
+    /**
+     * Converts `value` to property path array if it's not one.
+     *
+     * @private
+     * @param {*} value The value to process.
+     * @returns {Array} Returns the property path array.
+     */
+    function toPath(value) {
+      if (isArray(value)) {
+        return value;
+      }
+      var result = [];
+      baseToString(value).replace(rePropName, function(match, number, quote, string) {
+        result.push(quote ? string.replace(reEscapeChar, '$1') : (number || match));
       });
       return result;
     }
 
     /**
-     * Performs a deep comparison between two values to determine if they are
-     * equivalent to each other. If a callback is provided it will be executed
-     * to compare values. If the callback returns `undefined` comparisons will
-     * be handled by the method instead. The callback is bound to `thisArg` and
-     * invoked with two arguments; (a, b).
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} a The value to compare.
-     * @param {*} b The other value to compare.
-     * @param {Function} [callback] The function to customize comparing values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
-     * @example
-     *
-     * var object = { 'name': 'fred' };
-     * var copy = { 'name': 'fred' };
-     *
-     * object == copy;
-     * // => false
-     *
-     * _.isEqual(object, copy);
-     * // => true
-     *
-     * var words = ['hello', 'goodbye'];
-     * var otherWords = ['hi', 'goodbye'];
-     *
-     * _.isEqual(words, otherWords, function(a, b) {
-     *   var reGreet = /^(?:hello|hi)$/i,
-     *       aGreet = _.isString(a) && reGreet.test(a),
-     *       bGreet = _.isString(b) && reGreet.test(b);
-     *
-     *   return (aGreet || bGreet) ? (aGreet == bGreet) : undefined;
+     * Creates a clone of `wrapper`.
+     *
+     * @private
+     * @param {Object} wrapper The wrapper to clone.
+     * @returns {Object} Returns the cloned wrapper.
+     */
+    function wrapperClone(wrapper) {
+      return wrapper instanceof LazyWrapper
+        ? wrapper.clone()
+        : new LodashWrapper(wrapper.__wrapped__, wrapper.__chain__, arrayCopy(wrapper.__actions__));
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates an array of elements split into groups the length of `size`.
+     * If `collection` can't be split evenly, the final chunk will be the remaining
+     * elements.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to process.
+     * @param {number} [size=1] The length of each chunk.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the new array containing chunks.
+     * @example
+     *
+     * _.chunk(['a', 'b', 'c', 'd'], 2);
+     * // => [['a', 'b'], ['c', 'd']]
+     *
+     * _.chunk(['a', 'b', 'c', 'd'], 3);
+     * // => [['a', 'b', 'c'], ['d']]
+     */
+    function chunk(array, size, guard) {
+      if (guard ? isIterateeCall(array, size, guard) : size == null) {
+        size = 1;
+      } else {
+        size = nativeMax(nativeFloor(size) || 1, 1);
+      }
+      var index = 0,
+          length = array ? array.length : 0,
+          resIndex = -1,
+          result = Array(nativeCeil(length / size));
+
+      while (index < length) {
+        result[++resIndex] = baseSlice(array, index, (index += size));
+      }
+      return result;
+    }
+
+    /**
+     * Creates an array with all falsey values removed. The values `false`, `null`,
+     * `0`, `""`, `undefined`, and `NaN` are falsey.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to compact.
+     * @returns {Array} Returns the new array of filtered values.
+     * @example
+     *
+     * _.compact([0, 1, false, 2, '', 3]);
+     * // => [1, 2, 3]
+     */
+    function compact(array) {
+      var index = -1,
+          length = array ? array.length : 0,
+          resIndex = -1,
+          result = [];
+
+      while (++index < length) {
+        var value = array[index];
+        if (value) {
+          result[++resIndex] = value;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Creates an array of unique `array` values not included in the other
+     * provided arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {...Array} [values] The arrays of values to exclude.
+     * @returns {Array} Returns the new array of filtered values.
+     * @example
+     *
+     * _.difference([1, 2, 3], [4, 2]);
+     * // => [1, 3]
+     */
+    var difference = restParam(function(array, values) {
+      return (isObjectLike(array) && isArrayLike(array))
+        ? baseDifference(array, baseFlatten(values, false, true))
+        : [];
+    });
+
+    /**
+     * Creates a slice of `array` with `n` elements dropped from the beginning.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to drop.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.drop([1, 2, 3]);
+     * // => [2, 3]
+     *
+     * _.drop([1, 2, 3], 2);
+     * // => [3]
+     *
+     * _.drop([1, 2, 3], 5);
+     * // => []
+     *
+     * _.drop([1, 2, 3], 0);
+     * // => [1, 2, 3]
+     */
+    function drop(array, n, guard) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (guard ? isIterateeCall(array, n, guard) : n == null) {
+        n = 1;
+      }
+      return baseSlice(array, n < 0 ? 0 : n);
+    }
+
+    /**
+     * Creates a slice of `array` with `n` elements dropped from the end.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to drop.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.dropRight([1, 2, 3]);
+     * // => [1, 2]
+     *
+     * _.dropRight([1, 2, 3], 2);
+     * // => [1]
+     *
+     * _.dropRight([1, 2, 3], 5);
+     * // => []
+     *
+     * _.dropRight([1, 2, 3], 0);
+     * // => [1, 2, 3]
+     */
+    function dropRight(array, n, guard) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (guard ? isIterateeCall(array, n, guard) : n == null) {
+        n = 1;
+      }
+      n = length - (+n || 0);
+      return baseSlice(array, 0, n < 0 ? 0 : n);
+    }
+
+    /**
+     * Creates a slice of `array` excluding elements dropped from the end.
+     * Elements are dropped until `predicate` returns falsey. The predicate is
+     * bound to `thisArg` and invoked with three arguments: (value, index, array).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that match the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.dropRightWhile([1, 2, 3], function(n) {
+     *   return n > 1;
+     * });
+     * // => [1]
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': true },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': false }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.dropRightWhile(users, { 'user': 'pebbles', 'active': false }), 'user');
+     * // => ['barney', 'fred']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.dropRightWhile(users, 'active', false), 'user');
+     * // => ['barney']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.dropRightWhile(users, 'active'), 'user');
+     * // => ['barney', 'fred', 'pebbles']
+     */
+    function dropRightWhile(array, predicate, thisArg) {
+      return (array && array.length)
+        ? baseWhile(array, getCallback(predicate, thisArg, 3), true, true)
+        : [];
+    }
+
+    /**
+     * Creates a slice of `array` excluding elements dropped from the beginning.
+     * Elements are dropped until `predicate` returns falsey. The predicate is
+     * bound to `thisArg` and invoked with three arguments: (value, index, array).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.dropWhile([1, 2, 3], function(n) {
+     *   return n < 3;
      * });
-     * // => true
-     */
-    function isEqual(a, b, callback, thisArg) {
-      return baseIsEqual(a, b, typeof callback == 'function' && baseCreateCallback(callback, thisArg, 2));
-    }
-
-    /**
-     * Checks if `value` is, or can be coerced to, a finite number.
-     *
-     * Note: This is not the same as native `isFinite` which will return true for
-     * booleans and empty strings. See http://es5.github.io/#x15.1.2.5.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is finite, else `false`.
-     * @example
-     *
-     * _.isFinite(-101);
-     * // => true
-     *
-     * _.isFinite('10');
-     * // => true
-     *
-     * _.isFinite(true);
-     * // => false
-     *
-     * _.isFinite('');
-     * // => false
-     *
-     * _.isFinite(Infinity);
-     * // => false
-     */
-    function isFinite(value) {
-      return nativeIsFinite(value) && !nativeIsNaN(parseFloat(value));
-    }
-
-    /**
-     * Checks if `value` is a function.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a function, else `false`.
-     * @example
-     *
-     * _.isFunction(_);
-     * // => true
-     */
-    function isFunction(value) {
-      return typeof value == 'function';
-    }
-
-    /**
-     * Checks if `value` is the language type of Object.
-     * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is an object, else `false`.
-     * @example
-     *
-     * _.isObject({});
-     * // => true
-     *
-     * _.isObject([1, 2, 3]);
-     * // => true
-     *
-     * _.isObject(1);
-     * // => false
-     */
-    function isObject(value) {
-      // check if the value is the ECMAScript language type of Object
-      // http://es5.github.io/#x8
-      // and avoid a V8 bug
-      // http://code.google.com/p/v8/issues/detail?id=2291
-      return !!(value && objectTypes[typeof value]);
-    }
-
-    /**
-     * Checks if `value` is `NaN`.
-     *
-     * Note: This is not the same as native `isNaN` which will return `true` for
-     * `undefined` and other non-numeric values. See http://es5.github.io/#x15.1.2.4.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is `NaN`, else `false`.
-     * @example
-     *
-     * _.isNaN(NaN);
-     * // => true
-     *
-     * _.isNaN(new Number(NaN));
-     * // => true
-     *
-     * isNaN(undefined);
-     * // => true
-     *
-     * _.isNaN(undefined);
-     * // => false
-     */
-    function isNaN(value) {
-      // `NaN` as a primitive is the only value that is not equal to itself
-      // (perform the [[Class]] check first to avoid errors with some host objects in IE)
-      return isNumber(value) && value != +value;
-    }
-
-    /**
-     * Checks if `value` is `null`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is `null`, else `false`.
-     * @example
-     *
-     * _.isNull(null);
-     * // => true
-     *
-     * _.isNull(undefined);
-     * // => false
-     */
-    function isNull(value) {
-      return value === null;
-    }
-
-    /**
-     * Checks if `value` is a number.
-     *
-     * Note: `NaN` is considered a number. See http://es5.github.io/#x8.5.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a number, else `false`.
-     * @example
-     *
-     * _.isNumber(8.4 * 5);
-     * // => true
-     */
-    function isNumber(value) {
-      return typeof value == 'number' ||
-        value && typeof value == 'object' && toString.call(value) == numberClass || false;
-    }
-
-    /**
-     * Checks if `value` is an object created by the `Object` constructor.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
-     * @example
-     *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
-     *
-     * _.isPlainObject(new Shape);
-     * // => false
-     *
-     * _.isPlainObject([1, 2, 3]);
-     * // => false
-     *
-     * _.isPlainObject({ 'x': 0, 'y': 0 });
-     * // => true
-     */
-    var isPlainObject = !getPrototypeOf ? shimIsPlainObject : function(value) {
-      if (!(value && toString.call(value) == objectClass)) {
-        return false;
-      }
-      var valueOf = value.valueOf,
-          objProto = isNative(valueOf) && (objProto = getPrototypeOf(valueOf)) && getPrototypeOf(objProto);
-
-      return objProto
-        ? (value == objProto || getPrototypeOf(value) == objProto)
-        : shimIsPlainObject(value);
-    };
-
-    /**
-     * Checks if `value` is a regular expression.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a regular expression, else `false`.
-     * @example
-     *
-     * _.isRegExp(/fred/);
-     * // => true
-     */
-    function isRegExp(value) {
-      return value && typeof value == 'object' && toString.call(value) == regexpClass || false;
-    }
-
-    /**
-     * Checks if `value` is a string.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a string, else `false`.
-     * @example
-     *
-     * _.isString('fred');
-     * // => true
-     */
-    function isString(value) {
-      return typeof value == 'string' ||
-        value && typeof value == 'object' && toString.call(value) == stringClass || false;
-    }
-
-    /**
-     * Checks if `value` is `undefined`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is `undefined`, else `false`.
-     * @example
-     *
-     * _.isUndefined(void 0);
-     * // => true
-     */
-    function isUndefined(value) {
-      return typeof value == 'undefined';
-    }
-
-    /**
-     * Creates an object with the same keys as `object` and values generated by
-     * running each own enumerable property of `object` through the callback.
-     * The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, key, object).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new object with values of the results of each `callback` execution.
-     * @example
-     *
-     * _.mapValues({ 'a': 1, 'b': 2, 'c': 3} , function(num) { return num * 3; });
-     * // => { 'a': 3, 'b': 6, 'c': 9 }
-     *
-     * var characters = {
-     *   'fred': { 'name': 'fred', 'age': 40 },
-     *   'pebbles': { 'name': 'pebbles', 'age': 1 }
-     * };
-     *
-     * // using "_.pluck" callback shorthand
-     * _.mapValues(characters, 'age');
-     * // => { 'fred': 40, 'pebbles': 1 }
-     */
-    function mapValues(object, callback, thisArg) {
-      var result = {};
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      forOwn(object, function(value, key, object) {
-        result[key] = callback(value, key, object);
-      });
+     * // => [3]
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': false },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': true }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.dropWhile(users, { 'user': 'barney', 'active': false }), 'user');
+     * // => ['fred', 'pebbles']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.dropWhile(users, 'active', false), 'user');
+     * // => ['pebbles']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.dropWhile(users, 'active'), 'user');
+     * // => ['barney', 'fred', 'pebbles']
+     */
+    function dropWhile(array, predicate, thisArg) {
+      return (array && array.length)
+        ? baseWhile(array, getCallback(predicate, thisArg, 3), true)
+        : [];
+    }
+
+    /**
+     * Fills elements of `array` with `value` from `start` up to, but not
+     * including, `end`.
+     *
+     * **Note:** This method mutates `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to fill.
+     * @param {*} value The value to fill `array` with.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns `array`.
+     * @example
+     *
+     * var array = [1, 2, 3];
+     *
+     * _.fill(array, 'a');
+     * console.log(array);
+     * // => ['a', 'a', 'a']
+     *
+     * _.fill(Array(3), 2);
+     * // => [2, 2, 2]
+     *
+     * _.fill([4, 6, 8], '*', 1, 2);
+     * // => [4, '*', 8]
+     */
+    function fill(array, value, start, end) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (start && typeof start != 'number' && isIterateeCall(array, value, start)) {
+        start = 0;
+        end = length;
+      }
+      return baseFill(array, value, start, end);
+    }
+
+    /**
+     * This method is like `_.find` except that it returns the index of the first
+     * element `predicate` returns truthy for instead of the element itself.
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {number} Returns the index of the found element, else `-1`.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': false },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': true }
+     * ];
+     *
+     * _.findIndex(users, function(chr) {
+     *   return chr.user == 'barney';
+     * });
+     * // => 0
+     *
+     * // using the `_.matches` callback shorthand
+     * _.findIndex(users, { 'user': 'fred', 'active': false });
+     * // => 1
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.findIndex(users, 'active', false);
+     * // => 0
+     *
+     * // using the `_.property` callback shorthand
+     * _.findIndex(users, 'active');
+     * // => 2
+     */
+    var findIndex = createFindIndex();
+
+    /**
+     * This method is like `_.findIndex` except that it iterates over elements
+     * of `collection` from right to left.
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {number} Returns the index of the found element, else `-1`.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': true },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': false }
+     * ];
+     *
+     * _.findLastIndex(users, function(chr) {
+     *   return chr.user == 'pebbles';
+     * });
+     * // => 2
+     *
+     * // using the `_.matches` callback shorthand
+     * _.findLastIndex(users, { 'user': 'barney', 'active': true });
+     * // => 0
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.findLastIndex(users, 'active', false);
+     * // => 2
+     *
+     * // using the `_.property` callback shorthand
+     * _.findLastIndex(users, 'active');
+     * // => 0
+     */
+    var findLastIndex = createFindIndex(true);
+
+    /**
+     * Gets the first element of `array`.
+     *
+     * @static
+     * @memberOf _
+     * @alias head
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {*} Returns the first element of `array`.
+     * @example
+     *
+     * _.first([1, 2, 3]);
+     * // => 1
+     *
+     * _.first([]);
+     * // => undefined
+     */
+    function first(array) {
+      return array ? array[0] : undefined;
+    }
+
+    /**
+     * Flattens a nested array. If `isDeep` is `true` the array is recursively
+     * flattened, otherwise it's only flattened a single level.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to flatten.
+     * @param {boolean} [isDeep] Specify a deep flatten.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the new flattened array.
+     * @example
+     *
+     * _.flatten([1, [2, 3, [4]]]);
+     * // => [1, 2, 3, [4]]
+     *
+     * // using `isDeep`
+     * _.flatten([1, [2, 3, [4]]], true);
+     * // => [1, 2, 3, 4]
+     */
+    function flatten(array, isDeep, guard) {
+      var length = array ? array.length : 0;
+      if (guard && isIterateeCall(array, isDeep, guard)) {
+        isDeep = false;
+      }
+      return length ? baseFlatten(array, isDeep) : [];
+    }
+
+    /**
+     * Recursively flattens a nested array.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to recursively flatten.
+     * @returns {Array} Returns the new flattened array.
+     * @example
+     *
+     * _.flattenDeep([1, [2, 3, [4]]]);
+     * // => [1, 2, 3, 4]
+     */
+    function flattenDeep(array) {
+      var length = array ? array.length : 0;
+      return length ? baseFlatten(array, true) : [];
+    }
+
+    /**
+     * Gets the index at which the first occurrence of `value` is found in `array`
+     * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons. If `fromIndex` is negative, it's used as the offset
+     * from the end of `array`. If `array` is sorted providing `true` for `fromIndex`
+     * performs a faster binary search.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to search.
+     * @param {*} value The value to search for.
+     * @param {boolean|number} [fromIndex=0] The index to search from or `true`
+     *  to perform a binary search on a sorted array.
+     * @returns {number} Returns the index of the matched value, else `-1`.
+     * @example
+     *
+     * _.indexOf([1, 2, 1, 2], 2);
+     * // => 1
+     *
+     * // using `fromIndex`
+     * _.indexOf([1, 2, 1, 2], 2, 2);
+     * // => 3
+     *
+     * // performing a binary search
+     * _.indexOf([1, 1, 2, 2], 2, true);
+     * // => 2
+     */
+    function indexOf(array, value, fromIndex) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return -1;
+      }
+      if (typeof fromIndex == 'number') {
+        fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : fromIndex;
+      } else if (fromIndex) {
+        var index = binaryIndex(array, value);
+        if (index < length &&
+            (value === value ? (value === array[index]) : (array[index] !== array[index]))) {
+          return index;
+        }
+        return -1;
+      }
+      return baseIndexOf(array, value, fromIndex || 0);
+    }
+
+    /**
+     * Gets all but the last element of `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.initial([1, 2, 3]);
+     * // => [1, 2]
+     */
+    function initial(array) {
+      return dropRight(array, 1);
+    }
+
+    /**
+     * Creates an array of unique values that are included in all of the provided
+     * arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @returns {Array} Returns the new array of shared values.
+     * @example
+     * _.intersection([1, 2], [4, 2], [2, 1]);
+     * // => [2]
+     */
+    var intersection = restParam(function(arrays) {
+      var othLength = arrays.length,
+          othIndex = othLength,
+          caches = Array(length),
+          indexOf = getIndexOf(),
+          isCommon = indexOf === baseIndexOf,
+          result = [];
+
+      while (othIndex--) {
+        var value = arrays[othIndex] = isArrayLike(value = arrays[othIndex]) ? value : [];
+        caches[othIndex] = (isCommon && value.length >= 120) ? createCache(othIndex && value) : null;
+      }
+      var array = arrays[0],
+          index = -1,
+          length = array ? array.length : 0,
+          seen = caches[0];
+
+      outer:
+      while (++index < length) {
+        value = array[index];
+        if ((seen ? cacheIndexOf(seen, value) : indexOf(result, value, 0)) < 0) {
+          var othIndex = othLength;
+          while (--othIndex) {
+            var cache = caches[othIndex];
+            if ((cache ? cacheIndexOf(cache, value) : indexOf(arrays[othIndex], value, 0)) < 0) {
+              continue outer;
+            }
+          }
+          if (seen) {
+            seen.push(value);
+          }
+          result.push(value);
+        }
+      }
       return result;
-    }
-
-    /**
-     * Recursively merges own enumerable properties of the source object(s), that
-     * don't resolve to `undefined` into the destination object. Subsequent sources
-     * will overwrite property assignments of previous sources. If a callback is
-     * provided it will be executed to produce the merged values of the destination
-     * and source properties. If the callback returns `undefined` merging will
-     * be handled by the method instead. The callback is bound to `thisArg` and
-     * invoked with two arguments; (objectValue, sourceValue).
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The destination object.
-     * @param {...Object} [source] The source objects.
-     * @param {Function} [callback] The function to customize merging properties.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns the destination object.
-     * @example
-     *
-     * var names = {
-     *   'characters': [
-     *     { 'name': 'barney' },
-     *     { 'name': 'fred' }
-     *   ]
-     * };
-     *
-     * var ages = {
-     *   'characters': [
-     *     { 'age': 36 },
-     *     { 'age': 40 }
-     *   ]
-     * };
-     *
-     * _.merge(names, ages);
-     * // => { 'characters': [{ 'name': 'barney', 'age': 36 }, { 'name': 'fred', 'age': 40 }] }
-     *
-     * var food = {
-     *   'fruits': ['apple'],
-     *   'vegetables': ['beet']
-     * };
-     *
-     * var otherFood = {
-     *   'fruits': ['banana'],
-     *   'vegetables': ['carrot']
-     * };
-     *
-     * _.merge(food, otherFood, function(a, b) {
-     *   return _.isArray(a) ? a.concat(b) : undefined;
-     * });
-     * // => { 'fruits': ['apple', 'banana'], 'vegetables': ['beet', 'carrot] }
-     */
-    function merge(object) {
+    });
+
+    /**
+     * Gets the last element of `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {*} Returns the last element of `array`.
+     * @example
+     *
+     * _.last([1, 2, 3]);
+     * // => 3
+     */
+    function last(array) {
+      var length = array ? array.length : 0;
+      return length ? array[length - 1] : undefined;
+    }
+
+    /**
+     * This method is like `_.indexOf` except that it iterates over elements of
+     * `array` from right to left.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to search.
+     * @param {*} value The value to search for.
+     * @param {boolean|number} [fromIndex=array.length-1] The index to search from
+     *  or `true` to perform a binary search on a sorted array.
+     * @returns {number} Returns the index of the matched value, else `-1`.
+     * @example
+     *
+     * _.lastIndexOf([1, 2, 1, 2], 2);
+     * // => 3
+     *
+     * // using `fromIndex`
+     * _.lastIndexOf([1, 2, 1, 2], 2, 2);
+     * // => 1
+     *
+     * // performing a binary search
+     * _.lastIndexOf([1, 1, 2, 2], 2, true);
+     * // => 3
+     */
+    function lastIndexOf(array, value, fromIndex) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return -1;
+      }
+      var index = length;
+      if (typeof fromIndex == 'number') {
+        index = (fromIndex < 0 ? nativeMax(length + fromIndex, 0) : nativeMin(fromIndex || 0, length - 1)) + 1;
+      } else if (fromIndex) {
+        index = binaryIndex(array, value, true) - 1;
+        var other = array[index];
+        if (value === value ? (value === other) : (other !== other)) {
+          return index;
+        }
+        return -1;
+      }
+      if (value !== value) {
+        return indexOfNaN(array, index, true);
+      }
+      while (index--) {
+        if (array[index] === value) {
+          return index;
+        }
+      }
+      return -1;
+    }
+
+    /**
+     * Removes all provided values from `array` using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * **Note:** Unlike `_.without`, this method mutates `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {...*} [values] The values to remove.
+     * @returns {Array} Returns `array`.
+     * @example
+     *
+     * var array = [1, 2, 3, 1, 2, 3];
+     *
+     * _.pull(array, 2, 3);
+     * console.log(array);
+     * // => [1, 1]
+     */
+    function pull() {
       var args = arguments,
-          length = 2;
-
-      if (!isObject(object)) {
-        return object;
-      }
-      // allows working with `_.reduce` and `_.reduceRight` without using
-      // their `index` and `collection` arguments
-      if (typeof args[2] != 'number') {
-        length = args.length;
-      }
-      if (length > 3 && typeof args[length - 2] == 'function') {
-        var callback = baseCreateCallback(args[--length - 1], args[length--], 2);
-      } else if (length > 2 && typeof args[length - 1] == 'function') {
-        callback = args[--length];
-      }
-      var sources = slice(arguments, 1, length),
-          index = -1,
-          stackA = getArray(),
-          stackB = getArray();
+          array = args[0];
+
+      if (!(array && array.length)) {
+        return array;
+      }
+      var index = 0,
+          indexOf = getIndexOf(),
+          length = args.length;
 
       while (++index < length) {
-        baseMerge(object, sources[index], callback, stackA, stackB);
-      }
-      releaseArray(stackA);
-      releaseArray(stackB);
-      return object;
-    }
-
-    /**
-     * Creates a shallow clone of `object` excluding the specified properties.
-     * Property names may be specified as individual arguments or as arrays of
-     * property names. If a callback is provided it will be executed for each
-     * property of `object` omitting the properties the callback returns truey
-     * for. The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, key, object).
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The source object.
-     * @param {Function|...string|string[]} [callback] The properties to omit or the
-     *  function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns an object without the omitted properties.
-     * @example
-     *
-     * _.omit({ 'name': 'fred', 'age': 40 }, 'age');
-     * // => { 'name': 'fred' }
-     *
-     * _.omit({ 'name': 'fred', 'age': 40 }, function(value) {
-     *   return typeof value == 'number';
+        var fromIndex = 0,
+            value = args[index];
+
+        while ((fromIndex = indexOf(array, value, fromIndex)) > -1) {
+          splice.call(array, fromIndex, 1);
+        }
+      }
+      return array;
+    }
+
+    /**
+     * Removes elements from `array` corresponding to the given indexes and returns
+     * an array of the removed elements. Indexes may be specified as an array of
+     * indexes or as individual arguments.
+     *
+     * **Note:** Unlike `_.at`, this method mutates `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {...(number|number[])} [indexes] The indexes of elements to remove,
+     *  specified as individual indexes or arrays of indexes.
+     * @returns {Array} Returns the new array of removed elements.
+     * @example
+     *
+     * var array = [5, 10, 15, 20];
+     * var evens = _.pullAt(array, 1, 3);
+     *
+     * console.log(array);
+     * // => [5, 15]
+     *
+     * console.log(evens);
+     * // => [10, 20]
+     */
+    var pullAt = restParam(function(array, indexes) {
+      indexes = baseFlatten(indexes);
+
+      var result = baseAt(array, indexes);
+      basePullAt(array, indexes.sort(baseCompareAscending));
+      return result;
+    });
+
+    /**
+     * Removes all elements from `array` that `predicate` returns truthy for
+     * and returns an array of the removed elements. The predicate is bound to
+     * `thisArg` and invoked with three arguments: (value, index, array).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * **Note:** Unlike `_.filter`, this method mutates `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the new array of removed elements.
+     * @example
+     *
+     * var array = [1, 2, 3, 4];
+     * var evens = _.remove(array, function(n) {
+     *   return n % 2 == 0;
      * });
-     * // => { 'name': 'fred' }
-     */
-    function omit(object, callback, thisArg) {
-      var result = {};
-      if (typeof callback != 'function') {
-        var props = [];
-        forIn(object, function(value, key) {
-          props.push(key);
-        });
-        props = baseDifference(props, baseFlatten(arguments, true, false, 1));
-
-        var index = -1,
-            length = props.length;
-
-        while (++index < length) {
-          var key = props[index];
-          result[key] = object[key];
-        }
-      } else {
-        callback = lodash.createCallback(callback, thisArg, 3);
-        forIn(object, function(value, key, object) {
-          if (!callback(value, key, object)) {
-            result[key] = value;
-          }
-        });
-      }
+     *
+     * console.log(array);
+     * // => [1, 3]
+     *
+     * console.log(evens);
+     * // => [2, 4]
+     */
+    function remove(array, predicate, thisArg) {
+      var result = [];
+      if (!(array && array.length)) {
+        return result;
+      }
+      var index = -1,
+          indexes = [],
+          length = array.length;
+
+      predicate = getCallback(predicate, thisArg, 3);
+      while (++index < length) {
+        var value = array[index];
+        if (predicate(value, index, array)) {
+          result.push(value);
+          indexes.push(index);
+        }
+      }
+      basePullAt(array, indexes);
       return result;
     }
 
     /**
-     * Creates a two dimensional array of an object's key-value pairs,
-     * i.e. `[[key1, value1], [key2, value2]]`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns new array of key-value pairs.
-     * @example
-     *
-     * _.pairs({ 'barney': 36, 'fred': 40 });
-     * // => [['barney', 36], ['fred', 40]] (property order is not guaranteed across environments)
-     */
-    function pairs(object) {
+     * Gets all but the first element of `array`.
+     *
+     * @static
+     * @memberOf _
+     * @alias tail
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.rest([1, 2, 3]);
+     * // => [2, 3]
+     */
+    function rest(array) {
+      return drop(array, 1);
+    }
+
+    /**
+     * Creates a slice of `array` from `start` up to, but not including, `end`.
+     *
+     * **Note:** This method is used instead of `Array#slice` to support node
+     * lists in IE < 9 and to ensure dense arrays are returned.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to slice.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns the slice of `array`.
+     */
+    function slice(array, start, end) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (end && typeof end != 'number' && isIterateeCall(array, start, end)) {
+        start = 0;
+        end = length;
+      }
+      return baseSlice(array, start, end);
+    }
+
+    /**
+     * Uses a binary search to determine the lowest index at which `value` should
+     * be inserted into `array` in order to maintain its sort order. If an iteratee
+     * function is provided it's invoked for `value` and each element of `array`
+     * to compute their sort ranking. The iteratee is bound to `thisArg` and
+     * invoked with one argument; (value).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
+     * @example
+     *
+     * _.sortedIndex([30, 50], 40);
+     * // => 1
+     *
+     * _.sortedIndex([4, 4, 5, 5], 5);
+     * // => 2
+     *
+     * var dict = { 'data': { 'thirty': 30, 'forty': 40, 'fifty': 50 } };
+     *
+     * // using an iteratee function
+     * _.sortedIndex(['thirty', 'fifty'], 'forty', function(word) {
+     *   return this.data[word];
+     * }, dict);
+     * // => 1
+     *
+     * // using the `_.property` callback shorthand
+     * _.sortedIndex([{ 'x': 30 }, { 'x': 50 }], { 'x': 40 }, 'x');
+     * // => 1
+     */
+    var sortedIndex = createSortedIndex();
+
+    /**
+     * This method is like `_.sortedIndex` except that it returns the highest
+     * index at which `value` should be inserted into `array` in order to
+     * maintain its sort order.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
+     * @example
+     *
+     * _.sortedLastIndex([4, 4, 5, 5], 5);
+     * // => 4
+     */
+    var sortedLastIndex = createSortedIndex(true);
+
+    /**
+     * Creates a slice of `array` with `n` elements taken from the beginning.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to take.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.take([1, 2, 3]);
+     * // => [1]
+     *
+     * _.take([1, 2, 3], 2);
+     * // => [1, 2]
+     *
+     * _.take([1, 2, 3], 5);
+     * // => [1, 2, 3]
+     *
+     * _.take([1, 2, 3], 0);
+     * // => []
+     */
+    function take(array, n, guard) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (guard ? isIterateeCall(array, n, guard) : n == null) {
+        n = 1;
+      }
+      return baseSlice(array, 0, n < 0 ? 0 : n);
+    }
+
+    /**
+     * Creates a slice of `array` with `n` elements taken from the end.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to take.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.takeRight([1, 2, 3]);
+     * // => [3]
+     *
+     * _.takeRight([1, 2, 3], 2);
+     * // => [2, 3]
+     *
+     * _.takeRight([1, 2, 3], 5);
+     * // => [1, 2, 3]
+     *
+     * _.takeRight([1, 2, 3], 0);
+     * // => []
+     */
+    function takeRight(array, n, guard) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (guard ? isIterateeCall(array, n, guard) : n == null) {
+        n = 1;
+      }
+      n = length - (+n || 0);
+      return baseSlice(array, n < 0 ? 0 : n);
+    }
+
+    /**
+     * Creates a slice of `array` with elements taken from the end. Elements are
+     * taken until `predicate` returns falsey. The predicate is bound to `thisArg`
+     * and invoked with three arguments: (value, index, array).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.takeRightWhile([1, 2, 3], function(n) {
+     *   return n > 1;
+     * });
+     * // => [2, 3]
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': true },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': false }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.takeRightWhile(users, { 'user': 'pebbles', 'active': false }), 'user');
+     * // => ['pebbles']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.takeRightWhile(users, 'active', false), 'user');
+     * // => ['fred', 'pebbles']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.takeRightWhile(users, 'active'), 'user');
+     * // => []
+     */
+    function takeRightWhile(array, predicate, thisArg) {
+      return (array && array.length)
+        ? baseWhile(array, getCallback(predicate, thisArg, 3), false, true)
+        : [];
+    }
+
+    /**
+     * Creates a slice of `array` with elements taken from the beginning. Elements
+     * are taken until `predicate` returns falsey. The predicate is bound to
+     * `thisArg` and invoked with three arguments: (value, index, array).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.takeWhile([1, 2, 3], function(n) {
+     *   return n < 3;
+     * });
+     * // => [1, 2]
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': false },
+     *   { 'user': 'fred',    'active': false},
+     *   { 'user': 'pebbles', 'active': true }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.takeWhile(users, { 'user': 'barney', 'active': false }), 'user');
+     * // => ['barney']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.takeWhile(users, 'active', false), 'user');
+     * // => ['barney', 'fred']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.takeWhile(users, 'active'), 'user');
+     * // => []
+     */
+    function takeWhile(array, predicate, thisArg) {
+      return (array && array.length)
+        ? baseWhile(array, getCallback(predicate, thisArg, 3))
+        : [];
+    }
+
+    /**
+     * Creates an array of unique values, in order, from all of the provided arrays
+     * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @returns {Array} Returns the new array of combined values.
+     * @example
+     *
+     * _.union([1, 2], [4, 2], [2, 1]);
+     * // => [1, 2, 4]
+     */
+    var union = restParam(function(arrays) {
+      return baseUniq(baseFlatten(arrays, false, true));
+    });
+
+    /**
+     * Creates a duplicate-free version of an array, using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons, in which only the first occurence of each element
+     * is kept. Providing `true` for `isSorted` performs a faster search algorithm
+     * for sorted arrays. If an iteratee function is provided it's invoked for
+     * each element in the array to generate the criterion by which uniqueness
+     * is computed. The `iteratee` is bound to `thisArg` and invoked with three
+     * arguments: (value, index, array).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @alias unique
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {boolean} [isSorted] Specify the array is sorted.
+     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the new duplicate-value-free array.
+     * @example
+     *
+     * _.uniq([2, 1, 2]);
+     * // => [2, 1]
+     *
+     * // using `isSorted`
+     * _.uniq([1, 1, 2], true);
+     * // => [1, 2]
+     *
+     * // using an iteratee function
+     * _.uniq([1, 2.5, 1.5, 2], function(n) {
+     *   return this.floor(n);
+     * }, Math);
+     * // => [1, 2.5]
+     *
+     * // using the `_.property` callback shorthand
+     * _.uniq([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
+     * // => [{ 'x': 1 }, { 'x': 2 }]
+     */
+    function uniq(array, isSorted, iteratee, thisArg) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (isSorted != null && typeof isSorted != 'boolean') {
+        thisArg = iteratee;
+        iteratee = isIterateeCall(array, isSorted, thisArg) ? undefined : isSorted;
+        isSorted = false;
+      }
+      var callback = getCallback();
+      if (!(iteratee == null && callback === baseCallback)) {
+        iteratee = callback(iteratee, thisArg, 3);
+      }
+      return (isSorted && getIndexOf() === baseIndexOf)
+        ? sortedUniq(array, iteratee)
+        : baseUniq(array, iteratee);
+    }
+
+    /**
+     * This method is like `_.zip` except that it accepts an array of grouped
+     * elements and creates an array regrouping the elements to their pre-zip
+     * configuration.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array of grouped elements to process.
+     * @returns {Array} Returns the new array of regrouped elements.
+     * @example
+     *
+     * var zipped = _.zip(['fred', 'barney'], [30, 40], [true, false]);
+     * // => [['fred', 30, true], ['barney', 40, false]]
+     *
+     * _.unzip(zipped);
+     * // => [['fred', 'barney'], [30, 40], [true, false]]
+     */
+    function unzip(array) {
+      if (!(array && array.length)) {
+        return [];
+      }
       var index = -1,
-          props = keys(object),
-          length = props.length,
-          result = Array(length);
-
+          length = 0;
+
+      array = arrayFilter(array, function(group) {
+        if (isArrayLike(group)) {
+          length = nativeMax(group.length, length);
+          return true;
+        }
+      });
+      var result = Array(length);
       while (++index < length) {
-        var key = props[index];
-        result[index] = [key, object[key]];
-      }
-      return result;
-    }
-
-    /**
-     * Creates a shallow clone of `object` composed of the specified properties.
-     * Property names may be specified as individual arguments or as arrays of
-     * property names. If a callback is provided it will be executed for each
-     * property of `object` picking the properties the callback returns truey
-     * for. The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, key, object).
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The source object.
-     * @param {Function|...string|string[]} [callback] The function called per
-     *  iteration or property names to pick, specified as individual property
-     *  names or arrays of property names.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns an object composed of the picked properties.
-     * @example
-     *
-     * _.pick({ 'name': 'fred', '_userid': 'fred1' }, 'name');
-     * // => { 'name': 'fred' }
-     *
-     * _.pick({ 'name': 'fred', '_userid': 'fred1' }, function(value, key) {
-     *   return key.charAt(0) != '_';
-     * });
-     * // => { 'name': 'fred' }
-     */
-    function pick(object, callback, thisArg) {
-      var result = {};
-      if (typeof callback != 'function') {
-        var index = -1,
-            props = baseFlatten(arguments, true, false, 1),
-            length = isObject(object) ? props.length : 0;
-
-        while (++index < length) {
-          var key = props[index];
-          if (key in object) {
-            result[key] = object[key];
-          }
-        }
-      } else {
-        callback = lodash.createCallback(callback, thisArg, 3);
-        forIn(object, function(value, key, object) {
-          if (callback(value, key, object)) {
-            result[key] = value;
-          }
-        });
+        result[index] = arrayMap(array, baseProperty(index));
       }
       return result;
     }
 
     /**
-     * An alternative to `_.reduce` this method transforms `object` to a new
-     * `accumulator` object which is the result of running each of its own
-     * enumerable properties through a callback, with each callback execution
-     * potentially mutating the `accumulator` object. The callback is bound to
-     * `thisArg` and invoked with four arguments; (accumulator, value, key, object).
-     * Callbacks may exit iteration early by explicitly returning `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Array|Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [accumulator] The custom accumulator value.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the accumulated value.
-     * @example
-     *
-     * var squares = _.transform([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], function(result, num) {
-     *   num *= num;
-     *   if (num % 2) {
-     *     return result.push(num) < 3;
-     *   }
-     * });
-     * // => [1, 9, 25]
-     *
-     * var mapped = _.transform({ 'a': 1, 'b': 2, 'c': 3 }, function(result, num, key) {
-     *   result[key] = num * 3;
-     * });
-     * // => { 'a': 3, 'b': 6, 'c': 9 }
-     */
-    function transform(object, callback, accumulator, thisArg) {
-      var isArr = isArray(object);
-      if (accumulator == null) {
-        if (isArr) {
-          accumulator = [];
-        } else {
-          var ctor = object && object.constructor,
-              proto = ctor && ctor.prototype;
-
-          accumulator = baseCreate(proto);
-        }
-      }
-      if (callback) {
-        callback = lodash.createCallback(callback, thisArg, 4);
-        (isArr ? forEach : forOwn)(object, function(value, index, object) {
-          return callback(accumulator, value, index, object);
-        });
-      }
-      return accumulator;
-    }
-
-    /**
-     * Creates an array composed of the own enumerable property values of `object`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property values.
-     * @example
-     *
-     * _.values({ 'one': 1, 'two': 2, 'three': 3 });
-     * // => [1, 2, 3] (property order is not guaranteed across environments)
-     */
-    function values(object) {
+     * This method is like `_.unzip` except that it accepts an iteratee to specify
+     * how regrouped values should be combined. The `iteratee` is bound to `thisArg`
+     * and invoked with four arguments: (accumulator, value, index, group).
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array of grouped elements to process.
+     * @param {Function} [iteratee] The function to combine regrouped values.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the new array of regrouped elements.
+     * @example
+     *
+     * var zipped = _.zip([1, 2], [10, 20], [100, 200]);
+     * // => [[1, 10, 100], [2, 20, 200]]
+     *
+     * _.unzipWith(zipped, _.add);
+     * // => [3, 30, 300]
+     */
+    function unzipWith(array, iteratee, thisArg) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      var result = unzip(array);
+      if (iteratee == null) {
+        return result;
+      }
+      iteratee = bindCallback(iteratee, thisArg, 4);
+      return arrayMap(result, function(group) {
+        return arrayReduce(group, iteratee, undefined, true);
+      });
+    }
+
+    /**
+     * Creates an array excluding all provided values using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to filter.
+     * @param {...*} [values] The values to exclude.
+     * @returns {Array} Returns the new array of filtered values.
+     * @example
+     *
+     * _.without([1, 2, 1, 3], 1, 2);
+     * // => [3]
+     */
+    var without = restParam(function(array, values) {
+      return isArrayLike(array)
+        ? baseDifference(array, values)
+        : [];
+    });
+
+    /**
+     * Creates an array of unique values that is the [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
+     * of the provided arrays.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @returns {Array} Returns the new array of values.
+     * @example
+     *
+     * _.xor([1, 2], [4, 2]);
+     * // => [1, 4]
+     */
+    function xor() {
       var index = -1,
-          props = keys(object),
-          length = props.length,
-          result = Array(length);
+          length = arguments.length;
 
       while (++index < length) {
-        result[index] = object[props[index]];
+        var array = arguments[index];
+        if (isArrayLike(array)) {
+          var result = result
+            ? arrayPush(baseDifference(result, array), baseDifference(array, result))
+            : array;
+        }
+      }
+      return result ? baseUniq(result) : [];
+    }
+
+    /**
+     * Creates an array of grouped elements, the first of which contains the first
+     * elements of the given arrays, the second of which contains the second elements
+     * of the given arrays, and so on.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {...Array} [arrays] The arrays to process.
+     * @returns {Array} Returns the new array of grouped elements.
+     * @example
+     *
+     * _.zip(['fred', 'barney'], [30, 40], [true, false]);
+     * // => [['fred', 30, true], ['barney', 40, false]]
+     */
+    var zip = restParam(unzip);
+
+    /**
+     * The inverse of `_.pairs`; this method returns an object composed from arrays
+     * of property names and values. Provide either a single two dimensional array,
+     * e.g. `[[key1, value1], [key2, value2]]` or two arrays, one of property names
+     * and one of corresponding values.
+     *
+     * @static
+     * @memberOf _
+     * @alias object
+     * @category Array
+     * @param {Array} props The property names.
+     * @param {Array} [values=[]] The property values.
+     * @returns {Object} Returns the new object.
+     * @example
+     *
+     * _.zipObject([['fred', 30], ['barney', 40]]);
+     * // => { 'fred': 30, 'barney': 40 }
+     *
+     * _.zipObject(['fred', 'barney'], [30, 40]);
+     * // => { 'fred': 30, 'barney': 40 }
+     */
+    function zipObject(props, values) {
+      var index = -1,
+          length = props ? props.length : 0,
+          result = {};
+
+      if (length && !values && !isArray(props[0])) {
+        values = [];
+      }
+      while (++index < length) {
+        var key = props[index];
+        if (values) {
+          result[key] = values[index];
+        } else if (key) {
+          result[key[0]] = key[1];
+        }
       }
       return result;
     }
 
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates an array of elements from the specified indexes, or keys, of the
-     * `collection`. Indexes may be specified as individual arguments or as arrays
-     * of indexes.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {...(number|number[]|string|string[])} [index] The indexes of `collection`
-     *   to retrieve, specified as individual indexes or arrays of indexes.
-     * @returns {Array} Returns a new array of elements corresponding to the
-     *  provided indexes.
-     * @example
-     *
-     * _.at(['a', 'b', 'c', 'd', 'e'], [0, 2, 4]);
-     * // => ['a', 'c', 'e']
-     *
-     * _.at(['fred', 'barney', 'pebbles'], 0, 2);
-     * // => ['fred', 'pebbles']
-     */
-    function at(collection) {
-      var args = arguments,
-          index = -1,
-          props = baseFlatten(args, true, false, 1),
-          length = (args[2] && args[2][args[1]] === collection) ? 1 : props.length,
-          result = Array(length);
-
-      while(++index < length) {
-        result[index] = collection[props[index]];
-      }
+    /**
+     * This method is like `_.zip` except that it accepts an iteratee to specify
+     * how grouped values should be combined. The `iteratee` is bound to `thisArg`
+     * and invoked with four arguments: (accumulator, value, index, group).
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {...Array} [arrays] The arrays to process.
+     * @param {Function} [iteratee] The function to combine grouped values.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the new array of grouped elements.
+     * @example
+     *
+     * _.zipWith([1, 2], [10, 20], [100, 200], _.add);
+     * // => [111, 222]
+     */
+    var zipWith = restParam(function(arrays) {
+      var length = arrays.length,
+          iteratee = length > 2 ? arrays[length - 2] : undefined,
+          thisArg = length > 1 ? arrays[length - 1] : undefined;
+
+      if (length > 2 && typeof iteratee == 'function') {
+        length -= 2;
+      } else {
+        iteratee = (length > 1 && typeof thisArg == 'function') ? (--length, thisArg) : undefined;
+        thisArg = undefined;
+      }
+      arrays.length = length;
+      return unzipWith(arrays, iteratee, thisArg);
+    });
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a `lodash` object that wraps `value` with explicit method
+     * chaining enabled.
+     *
+     * @static
+     * @memberOf _
+     * @category Chain
+     * @param {*} value The value to wrap.
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney',  'age': 36 },
+     *   { 'user': 'fred',    'age': 40 },
+     *   { 'user': 'pebbles', 'age': 1 }
+     * ];
+     *
+     * var youngest = _.chain(users)
+     *   .sortBy('age')
+     *   .map(function(chr) {
+     *     return chr.user + ' is ' + chr.age;
+     *   })
+     *   .first()
+     *   .value();
+     * // => 'pebbles is 1'
+     */
+    function chain(value) {
+      var result = lodash(value);
+      result.__chain__ = true;
       return result;
     }
 
     /**
-     * Checks if a given value is present in a collection using strict equality
-     * for comparisons, i.e. `===`. If `fromIndex` is negative, it is used as the
-     * offset from the end of the collection.
-     *
-     * @static
-     * @memberOf _
-     * @alias include
-     * @category Collections
+     * This method invokes `interceptor` and returns `value`. The interceptor is
+     * bound to `thisArg` and invoked with one argument; (value). The purpose of
+     * this method is to "tap into" a method chain in order to perform operations
+     * on intermediate results within the chain.
+     *
+     * @static
+     * @memberOf _
+     * @category Chain
+     * @param {*} value The value to provide to `interceptor`.
+     * @param {Function} interceptor The function to invoke.
+     * @param {*} [thisArg] The `this` binding of `interceptor`.
+     * @returns {*} Returns `value`.
+     * @example
+     *
+     * _([1, 2, 3])
+     *  .tap(function(array) {
+     *    array.pop();
+     *  })
+     *  .reverse()
+     *  .value();
+     * // => [2, 1]
+     */
+    function tap(value, interceptor, thisArg) {
+      interceptor.call(thisArg, value);
+      return value;
+    }
+
+    /**
+     * This method is like `_.tap` except that it returns the result of `interceptor`.
+     *
+     * @static
+     * @memberOf _
+     * @category Chain
+     * @param {*} value The value to provide to `interceptor`.
+     * @param {Function} interceptor The function to invoke.
+     * @param {*} [thisArg] The `this` binding of `interceptor`.
+     * @returns {*} Returns the result of `interceptor`.
+     * @example
+     *
+     * _('  abc  ')
+     *  .chain()
+     *  .trim()
+     *  .thru(function(value) {
+     *    return [value];
+     *  })
+     *  .value();
+     * // => ['abc']
+     */
+    function thru(value, interceptor, thisArg) {
+      return interceptor.call(thisArg, value);
+    }
+
+    /**
+     * Enables explicit method chaining on the wrapper object.
+     *
+     * @name chain
+     * @memberOf _
+     * @category Chain
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 40 }
+     * ];
+     *
+     * // without explicit chaining
+     * _(users).first();
+     * // => { 'user': 'barney', 'age': 36 }
+     *
+     * // with explicit chaining
+     * _(users).chain()
+     *   .first()
+     *   .pick('user')
+     *   .value();
+     * // => { 'user': 'barney' }
+     */
+    function wrapperChain() {
+      return chain(this);
+    }
+
+    /**
+     * Executes the chained sequence and returns the wrapped result.
+     *
+     * @name commit
+     * @memberOf _
+     * @category Chain
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var array = [1, 2];
+     * var wrapped = _(array).push(3);
+     *
+     * console.log(array);
+     * // => [1, 2]
+     *
+     * wrapped = wrapped.commit();
+     * console.log(array);
+     * // => [1, 2, 3]
+     *
+     * wrapped.last();
+     * // => 3
+     *
+     * console.log(array);
+     * // => [1, 2, 3]
+     */
+    function wrapperCommit() {
+      return new LodashWrapper(this.value(), this.__chain__);
+    }
+
+    /**
+     * Creates a new array joining a wrapped array with any additional arrays
+     * and/or values.
+     *
+     * @name concat
+     * @memberOf _
+     * @category Chain
+     * @param {...*} [values] The values to concatenate.
+     * @returns {Array} Returns the new concatenated array.
+     * @example
+     *
+     * var array = [1];
+     * var wrapped = _(array).concat(2, [3], [[4]]);
+     *
+     * console.log(wrapped.value());
+     * // => [1, 2, 3, [4]]
+     *
+     * console.log(array);
+     * // => [1]
+     */
+    var wrapperConcat = restParam(function(values) {
+      values = baseFlatten(values);
+      return this.thru(function(array) {
+        return arrayConcat(isArray(array) ? array : [toObject(array)], values);
+      });
+    });
+
+    /**
+     * Creates a clone of the chained sequence planting `value` as the wrapped value.
+     *
+     * @name plant
+     * @memberOf _
+     * @category Chain
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var array = [1, 2];
+     * var wrapped = _(array).map(function(value) {
+     *   return Math.pow(value, 2);
+     * });
+     *
+     * var other = [3, 4];
+     * var otherWrapped = wrapped.plant(other);
+     *
+     * otherWrapped.value();
+     * // => [9, 16]
+     *
+     * wrapped.value();
+     * // => [1, 4]
+     */
+    function wrapperPlant(value) {
+      var result,
+          parent = this;
+
+      while (parent instanceof baseLodash) {
+        var clone = wrapperClone(parent);
+        if (result) {
+          previous.__wrapped__ = clone;
+        } else {
+          result = clone;
+        }
+        var previous = clone;
+        parent = parent.__wrapped__;
+      }
+      previous.__wrapped__ = value;
+      return result;
+    }
+
+    /**
+     * Reverses the wrapped array so the first element becomes the last, the
+     * second element becomes the second to last, and so on.
+     *
+     * **Note:** This method mutates the wrapped array.
+     *
+     * @name reverse
+     * @memberOf _
+     * @category Chain
+     * @returns {Object} Returns the new reversed `lodash` wrapper instance.
+     * @example
+     *
+     * var array = [1, 2, 3];
+     *
+     * _(array).reverse().value()
+     * // => [3, 2, 1]
+     *
+     * console.log(array);
+     * // => [3, 2, 1]
+     */
+    function wrapperReverse() {
+      var value = this.__wrapped__;
+
+      var interceptor = function(value) {
+        return value.reverse();
+      };
+      if (value instanceof LazyWrapper) {
+        var wrapped = value;
+        if (this.__actions__.length) {
+          wrapped = new LazyWrapper(this);
+        }
+        wrapped = wrapped.reverse();
+        wrapped.__actions__.push({ 'func': thru, 'args': [interceptor], 'thisArg': undefined });
+        return new LodashWrapper(wrapped, this.__chain__);
+      }
+      return this.thru(interceptor);
+    }
+
+    /**
+     * Produces the result of coercing the unwrapped value to a string.
+     *
+     * @name toString
+     * @memberOf _
+     * @category Chain
+     * @returns {string} Returns the coerced string value.
+     * @example
+     *
+     * _([1, 2, 3]).toString();
+     * // => '1,2,3'
+     */
+    function wrapperToString() {
+      return (this.value() + '');
+    }
+
+    /**
+     * Executes the chained sequence to extract the unwrapped value.
+     *
+     * @name value
+     * @memberOf _
+     * @alias run, toJSON, valueOf
+     * @category Chain
+     * @returns {*} Returns the resolved unwrapped value.
+     * @example
+     *
+     * _([1, 2, 3]).value();
+     * // => [1, 2, 3]
+     */
+    function wrapperValue() {
+      return baseWrapperValue(this.__wrapped__, this.__actions__);
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates an array of elements corresponding to the given keys, or indexes,
+     * of `collection`. Keys may be specified as individual arguments or as arrays
+     * of keys.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {*} target The value to check for.
-     * @param {number} [fromIndex=0] The index to search from.
-     * @returns {boolean} Returns `true` if the `target` element is found, else `false`.
-     * @example
-     *
-     * _.contains([1, 2, 3], 1);
-     * // => true
-     *
-     * _.contains([1, 2, 3], 1, 2);
-     * // => false
-     *
-     * _.contains({ 'name': 'fred', 'age': 40 }, 'fred');
-     * // => true
-     *
-     * _.contains('pebbles', 'eb');
-     * // => true
-     */
-    function contains(collection, target, fromIndex) {
-      var index = -1,
-          indexOf = getIndexOf(),
-          length = collection ? collection.length : 0,
-          result = false;
-
-      fromIndex = (fromIndex < 0 ? nativeMax(0, length + fromIndex) : fromIndex) || 0;
-      if (isArray(collection)) {
-        result = indexOf(collection, target, fromIndex) > -1;
-      } else if (typeof length == 'number') {
-        result = (isString(collection) ? collection.indexOf(target, fromIndex) : indexOf(collection, target, fromIndex)) > -1;
-      } else {
-        forOwn(collection, function(value) {
-          if (++index >= fromIndex) {
-            return !(result = value === target);
-          }
-        });
-      }
-      return result;
-    }
+     * @param {...(number|number[]|string|string[])} [props] The property names
+     *  or indexes of elements to pick, specified individually or in arrays.
+     * @returns {Array} Returns the new array of picked elements.
+     * @example
+     *
+     * _.at(['a', 'b', 'c'], [0, 2]);
+     * // => ['a', 'c']
+     *
+     * _.at(['barney', 'fred', 'pebbles'], 0, 2);
+     * // => ['barney', 'pebbles']
+     */
+    var at = restParam(function(collection, props) {
+      return baseAt(collection, baseFlatten(props));
+    });
 
     /**
      * Creates an object composed of keys generated from the results of running
-     * each element of `collection` through the callback. The corresponding value
-     * of each key is the number of times the key was returned by the callback.
-     * The callback is bound to `thisArg` and invoked with three arguments;
+     * each element of `collection` through `iteratee`. The corresponding value
+     * of each key is the number of times the key was returned by `iteratee`.
+     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
      * (value, index|key, collection).
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {Object} Returns the composed aggregate object.
      * @example
      *
-     * _.countBy([4.3, 6.1, 6.4], function(num) { return Math.floor(num); });
+     * _.countBy([4.3, 6.1, 6.4], function(n) {
+     *   return Math.floor(n);
+     * });
      * // => { '4': 1, '6': 2 }
      *
-     * _.countBy([4.3, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
+     * _.countBy([4.3, 6.1, 6.4], function(n) {
+     *   return this.floor(n);
+     * }, Math);
      * // => { '4': 1, '6': 2 }
      *
      * _.countBy(['one', 'two', 'three'], 'length');
      * // => { '3': 2, '5': 1 }
      */
     var countBy = createAggregator(function(result, value, key) {
-      (hasOwnProperty.call(result, key) ? result[key]++ : result[key] = 1);
+      hasOwnProperty.call(result, key) ? ++result[key] : (result[key] = 1);
     });
 
     /**
-     * Checks if the given callback returns truey value for **all** elements of
-     * a collection. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * Checks if `predicate` returns truthy for **all** elements of `collection`.
+     * The predicate is bound to `thisArg` and invoked with three arguments:
+     * (value, index|key, collection).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
      *
      * @static
      * @memberOf _
      * @alias all
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {boolean} Returns `true` if all elements passed the callback check,
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {boolean} Returns `true` if all elements pass the predicate check,
      *  else `false`.
      * @example
      *
-     * _.every([true, 1, null, 'yes']);
+     * _.every([true, 1, null, 'yes'], Boolean);
      * // => false
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * var users = [
+     *   { 'user': 'barney', 'active': false },
+     *   { 'user': 'fred',   'active': false }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.every(characters, 'age');
+     * // using the `_.matches` callback shorthand
+     * _.every(users, { 'user': 'barney', 'active': false });
+     * // => false
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.every(users, 'active', false);
      * // => true
      *
-     * // using "_.where" callback shorthand
-     * _.every(characters, { 'age': 36 });
+     * // using the `_.property` callback shorthand
+     * _.every(users, 'active');
      * // => false
      */
-    function every(collection, callback, thisArg) {
-      var result = true;
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      if (typeof length == 'number') {
-        while (++index < length) {
-          if (!(result = !!callback(collection[index], index, collection))) {
-            break;
-          }
-        }
-      } else {
-        forOwn(collection, function(value, index, collection) {
-          return (result = !!callback(value, index, collection));
-        });
-      }
-      return result;
-    }
-
-    /**
-     * Iterates over elements of a collection, returning an array of all elements
-     * the callback returns truey for. The callback is bound to `thisArg` and
-     * invoked with three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+    function every(collection, predicate, thisArg) {
+      var func = isArray(collection) ? arrayEvery : baseEvery;
+      if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
+        predicate = undefined;
+      }
+      if (typeof predicate != 'function' || thisArg !== undefined) {
+        predicate = getCallback(predicate, thisArg, 3);
+      }
+      return func(collection, predicate);
+    }
+
+    /**
+     * Iterates over elements of `collection`, returning an array of all elements
+     * `predicate` returns truthy for. The predicate is bound to `thisArg` and
+     * invoked with three arguments: (value, index|key, collection).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
      *
      * @static
      * @memberOf _
      * @alias select
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of elements that passed the callback check.
-     * @example
-     *
-     * var evens = _.filter([1, 2, 3, 4, 5, 6], function(num) { return num % 2 == 0; });
-     * // => [2, 4, 6]
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'blocked': false },
-     *   { 'name': 'fred',   'age': 40, 'blocked': true }
-     * ];
-     *
-     * // using "_.pluck" callback shorthand
-     * _.filter(characters, 'blocked');
-     * // => [{ 'name': 'fred', 'age': 40, 'blocked': true }]
-     *
-     * // using "_.where" callback shorthand
-     * _.filter(characters, { 'age': 36 });
-     * // => [{ 'name': 'barney', 'age': 36, 'blocked': false }]
-     */
-    function filter(collection, callback, thisArg) {
-      var result = [];
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      if (typeof length == 'number') {
-        while (++index < length) {
-          var value = collection[index];
-          if (callback(value, index, collection)) {
-            result.push(value);
-          }
-        }
-      } else {
-        forOwn(collection, function(value, index, collection) {
-          if (callback(value, index, collection)) {
-            result.push(value);
-          }
-        });
-      }
-      return result;
-    }
-
-    /**
-     * Iterates over elements of a collection, returning the first element that
-     * the callback returns truey for. The callback is bound to `thisArg` and
-     * invoked with three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @alias detect, findWhere
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the found element, else `undefined`.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36, 'blocked': false },
-     *   { 'name': 'fred',    'age': 40, 'blocked': true },
-     *   { 'name': 'pebbles', 'age': 1,  'blocked': false }
-     * ];
-     *
-     * _.find(characters, function(chr) {
-     *   return chr.age < 40;
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the new filtered array.
+     * @example
+     *
+     * _.filter([4, 5, 6], function(n) {
+     *   return n % 2 == 0;
      * });
-     * // => { 'name': 'barney', 'age': 36, 'blocked': false }
-     *
-     * // using "_.where" callback shorthand
-     * _.find(characters, { 'age': 1 });
-     * // =>  { 'name': 'pebbles', 'age': 1, 'blocked': false }
-     *
-     * // using "_.pluck" callback shorthand
-     * _.find(characters, 'blocked');
-     * // => { 'name': 'fred', 'age': 40, 'blocked': true }
-     */
-    function find(collection, callback, thisArg) {
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      if (typeof length == 'number') {
-        while (++index < length) {
-          var value = collection[index];
-          if (callback(value, index, collection)) {
-            return value;
-          }
-        }
-      } else {
-        var result;
-        forOwn(collection, function(value, index, collection) {
-          if (callback(value, index, collection)) {
-            result = value;
-            return false;
-          }
-        });
-        return result;
-      }
-    }
-
-    /**
-     * This method is like `_.find` except that it iterates over elements
-     * of a `collection` from right to left.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the found element, else `undefined`.
-     * @example
-     *
-     * _.findLast([1, 2, 3, 4], function(num) {
-     *   return num % 2 == 1;
+     * // => [4, 6]
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': true },
+     *   { 'user': 'fred',   'age': 40, 'active': false }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.filter(users, { 'age': 36, 'active': true }), 'user');
+     * // => ['barney']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.filter(users, 'active', false), 'user');
+     * // => ['fred']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.filter(users, 'active'), 'user');
+     * // => ['barney']
+     */
+    function filter(collection, predicate, thisArg) {
+      var func = isArray(collection) ? arrayFilter : baseFilter;
+      predicate = getCallback(predicate, thisArg, 3);
+      return func(collection, predicate);
+    }
+
+    /**
+     * Iterates over elements of `collection`, returning the first element
+     * `predicate` returns truthy for. The predicate is bound to `thisArg` and
+     * invoked with three arguments: (value, index|key, collection).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @alias detect
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {*} Returns the matched element, else `undefined`.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney',  'age': 36, 'active': true },
+     *   { 'user': 'fred',    'age': 40, 'active': false },
+     *   { 'user': 'pebbles', 'age': 1,  'active': true }
+     * ];
+     *
+     * _.result(_.find(users, function(chr) {
+     *   return chr.age < 40;
+     * }), 'user');
+     * // => 'barney'
+     *
+     * // using the `_.matches` callback shorthand
+     * _.result(_.find(users, { 'age': 1, 'active': true }), 'user');
+     * // => 'pebbles'
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.result(_.find(users, 'active', false), 'user');
+     * // => 'fred'
+     *
+     * // using the `_.property` callback shorthand
+     * _.result(_.find(users, 'active'), 'user');
+     * // => 'barney'
+     */
+    var find = createFind(baseEach);
+
+    /**
+     * This method is like `_.find` except that it iterates over elements of
+     * `collection` from right to left.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {*} Returns the matched element, else `undefined`.
+     * @example
+     *
+     * _.findLast([1, 2, 3, 4], function(n) {
+     *   return n % 2 == 1;
      * });
      * // => 3
      */
-    function findLast(collection, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      forEachRight(collection, function(value, index, collection) {
-        if (callback(value, index, collection)) {
-          result = value;
-          return false;
-        }
-      });
-      return result;
-    }
-
-    /**
-     * Iterates over elements of a collection, executing the callback for each
-     * element. The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, index|key, collection). Callbacks may exit iteration early by
-     * explicitly returning `false`.
-     *
-     * Note: As with other "Collections" methods, objects with a `length` property
+    var findLast = createFind(baseEachRight, true);
+
+    /**
+     * Performs a deep comparison between each element in `collection` and the
+     * source object, returning the first element that has equivalent property
+     * values.
+     *
+     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
+     * numbers, `Object` objects, regexes, and strings. Objects are compared by
+     * their own, not inherited, enumerable properties. For comparing a single
+     * own or inherited property value see `_.matchesProperty`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {Object} source The object of property values to match.
+     * @returns {*} Returns the matched element, else `undefined`.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': true },
+     *   { 'user': 'fred',   'age': 40, 'active': false }
+     * ];
+     *
+     * _.result(_.findWhere(users, { 'age': 36, 'active': true }), 'user');
+     * // => 'barney'
+     *
+     * _.result(_.findWhere(users, { 'age': 40, 'active': false }), 'user');
+     * // => 'fred'
+     */
+    function findWhere(collection, source) {
+      return find(collection, baseMatches(source));
+    }
+
+    /**
+     * Iterates over elements of `collection` invoking `iteratee` for each element.
+     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
+     * (value, index|key, collection). Iteratee functions may exit iteration early
+     * by explicitly returning `false`.
+     *
+     * **Note:** As with other "Collections" methods, objects with a "length" property
      * are iterated like arrays. To avoid this behavior `_.forIn` or `_.forOwn`
      * may be used for object iteration.
      *
      * @static
      * @memberOf _
      * @alias each
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {Array|Object|string} Returns `collection`.
      * @example
      *
-     * _([1, 2, 3]).forEach(function(num) { console.log(num); }).join(',');
-     * // => logs each number and returns '1,2,3'
-     *
-     * _.forEach({ 'one': 1, 'two': 2, 'three': 3 }, function(num) { console.log(num); });
-     * // => logs each number and returns the object (property order is not guaranteed across environments)
-     */
-    function forEach(collection, callback, thisArg) {
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      callback = callback && typeof thisArg == 'undefined' ? callback : baseCreateCallback(callback, thisArg, 3);
-      if (typeof length == 'number') {
-        while (++index < length) {
-          if (callback(collection[index], index, collection) === false) {
-            break;
-          }
-        }
-      } else {
-        forOwn(collection, callback);
-      }
-      return collection;
-    }
-
-    /**
-     * This method is like `_.forEach` except that it iterates over elements
-     * of a `collection` from right to left.
+     * _([1, 2]).forEach(function(n) {
+     *   console.log(n);
+     * }).value();
+     * // => logs each value from left to right and returns the array
+     *
+     * _.forEach({ 'a': 1, 'b': 2 }, function(n, key) {
+     *   console.log(n, key);
+     * });
+     * // => logs each value-key pair and returns the object (iteration order is not guaranteed)
+     */
+    var forEach = createForEach(arrayEach, baseEach);
+
+    /**
+     * This method is like `_.forEach` except that it iterates over elements of
+     * `collection` from right to left.
      *
      * @static
      * @memberOf _
      * @alias eachRight
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {Array|Object|string} Returns `collection`.
      * @example
      *
-     * _([1, 2, 3]).forEachRight(function(num) { console.log(num); }).join(',');
-     * // => logs each number from right to left and returns '3,2,1'
-     */
-    function forEachRight(collection, callback, thisArg) {
-      var length = collection ? collection.length : 0;
-      callback = callback && typeof thisArg == 'undefined' ? callback : baseCreateCallback(callback, thisArg, 3);
-      if (typeof length == 'number') {
-        while (length--) {
-          if (callback(collection[length], length, collection) === false) {
-            break;
-          }
-        }
+     * _([1, 2]).forEachRight(function(n) {
+     *   console.log(n);
+     * }).value();
+     * // => logs each value from right to left and returns the array
+     */
+    var forEachRight = createForEach(arrayEachRight, baseEachRight);
+
+    /**
+     * Creates an object composed of keys generated from the results of running
+     * each element of `collection` through `iteratee`. The corresponding value
+     * of each key is an array of the elements responsible for generating the key.
+     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
+     * (value, index|key, collection).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns the composed aggregate object.
+     * @example
+     *
+     * _.groupBy([4.2, 6.1, 6.4], function(n) {
+     *   return Math.floor(n);
+     * });
+     * // => { '4': [4.2], '6': [6.1, 6.4] }
+     *
+     * _.groupBy([4.2, 6.1, 6.4], function(n) {
+     *   return this.floor(n);
+     * }, Math);
+     * // => { '4': [4.2], '6': [6.1, 6.4] }
+     *
+     * // using the `_.property` callback shorthand
+     * _.groupBy(['one', 'two', 'three'], 'length');
+     * // => { '3': ['one', 'two'], '5': ['three'] }
+     */
+    var groupBy = createAggregator(function(result, value, key) {
+      if (hasOwnProperty.call(result, key)) {
+        result[key].push(value);
       } else {
-        var props = keys(collection);
-        length = props.length;
-        forOwn(collection, function(value, key, collection) {
-          key = props ? props[--length] : --length;
-          return callback(collection[key], key, collection);
-        });
-      }
-      return collection;
+        result[key] = [value];
+      }
+    });
+
+    /**
+     * Checks if `target` is in `collection` using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons. If `fromIndex` is negative, it's used as the offset
+     * from the end of `collection`.
+     *
+     * @static
+     * @memberOf _
+     * @alias contains, include
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {*} target The value to search for.
+     * @param {number} [fromIndex=0] The index to search from.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
+     * @returns {boolean} Returns `true` if a matching element is found, else `false`.
+     * @example
+     *
+     * _.includes([1, 2, 3], 1);
+     * // => true
+     *
+     * _.includes([1, 2, 3], 1, 2);
+     * // => false
+     *
+     * _.includes({ 'user': 'fred', 'age': 40 }, 'fred');
+     * // => true
+     *
+     * _.includes('pebbles', 'eb');
+     * // => true
+     */
+    function includes(collection, target, fromIndex, guard) {
+      var length = collection ? getLength(collection) : 0;
+      if (!isLength(length)) {
+        collection = values(collection);
+        length = collection.length;
+      }
+      if (typeof fromIndex != 'number' || (guard && isIterateeCall(target, fromIndex, guard))) {
+        fromIndex = 0;
+      } else {
+        fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : (fromIndex || 0);
+      }
+      return (typeof collection == 'string' || !isArray(collection) && isString(collection))
+        ? (fromIndex <= length && collection.indexOf(target, fromIndex) > -1)
+        : (!!length && getIndexOf(collection, target, fromIndex) > -1);
     }
 
     /**
      * Creates an object composed of keys generated from the results of running
-     * each element of a collection through the callback. The corresponding value
-     * of each key is an array of the elements responsible for generating the key.
-     * The callback is bound to `thisArg` and invoked with three arguments;
+     * each element of `collection` through `iteratee`. The corresponding value
+     * of each key is the last element responsible for generating the key. The
+     * iteratee function is bound to `thisArg` and invoked with three arguments:
      * (value, index|key, collection).
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {Object} Returns the composed aggregate object.
      * @example
      *
-     * _.groupBy([4.2, 6.1, 6.4], function(num) { return Math.floor(num); });
-     * // => { '4': [4.2], '6': [6.1, 6.4] }
-     *
-     * _.groupBy([4.2, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
-     * // => { '4': [4.2], '6': [6.1, 6.4] }
-     *
-     * // using "_.pluck" callback shorthand
-     * _.groupBy(['one', 'two', 'three'], 'length');
-     * // => { '3': ['one', 'two'], '5': ['three'] }
-     */
-    var groupBy = createAggregator(function(result, value, key) {
-      (hasOwnProperty.call(result, key) ? result[key] : result[key] = []).push(value);
-    });
-
-    /**
-     * Creates an object composed of keys generated from the results of running
-     * each element of the collection through the given callback. The corresponding
-     * value of each key is the last element responsible for generating the key.
-     * The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns the composed aggregate object.
-     * @example
-     *
-     * var keys = [
+     * var keyData = [
      *   { 'dir': 'left', 'code': 97 },
      *   { 'dir': 'right', 'code': 100 }
      * ];
      *
-     * _.indexBy(keys, 'dir');
+     * _.indexBy(keyData, 'dir');
      * // => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }
      *
-     * _.indexBy(keys, function(key) { return String.fromCharCode(key.code); });
+     * _.indexBy(keyData, function(object) {
+     *   return String.fromCharCode(object.code);
+     * });
      * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
      *
-     * _.indexBy(characters, function(key) { this.fromCharCode(key.code); }, String);
+     * _.indexBy(keyData, function(object) {
+     *   return this.fromCharCode(object.code);
+     * }, String);
      * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
      */
     var indexBy = createAggregator(function(result, value, key) {
@@ -3425,19 +6615,19 @@
     });
 
     /**
-     * Invokes the method named by `methodName` on each element in the `collection`
-     * returning an array of the results of each invoked method. Additional arguments
-     * will be provided to each invoked method. If `methodName` is a function it
-     * will be invoked for, and `this` bound to, each element in the `collection`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * Invokes the method at `path` of each element in `collection`, returning
+     * an array of the results of each invoked method. Any additional arguments
+     * are provided to each invoked method. If `methodName` is a function it's
+     * invoked for, and `this` bound to, each element in `collection`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|string} methodName The name of the method to invoke or
+     * @param {Array|Function|string} path The path of the method to invoke or
      *  the function invoked per iteration.
-     * @param {...*} [arg] Arguments to invoke the method with.
-     * @returns {Array} Returns a new array of the results of each invoked method.
+     * @param {...*} [args] The arguments to invoke the method with.
+     * @returns {Array} Returns the array of results.
      * @example
      *
      * _.invoke([[5, 1, 7], [3, 2, 1]], 'sort');
@@ -3446,390 +6636,288 @@
      * _.invoke([123, 456], String.prototype.split, '');
      * // => [['1', '2', '3'], ['4', '5', '6']]
      */
-    function invoke(collection, methodName) {
-      var args = slice(arguments, 2),
-          index = -1,
-          isFunc = typeof methodName == 'function',
-          length = collection ? collection.length : 0,
-          result = Array(typeof length == 'number' ? length : 0);
-
-      forEach(collection, function(value) {
-        result[++index] = (isFunc ? methodName : value[methodName]).apply(value, args);
+    var invoke = restParam(function(collection, path, args) {
+      var index = -1,
+          isFunc = typeof path == 'function',
+          isProp = isKey(path),
+          result = isArrayLike(collection) ? Array(collection.length) : [];
+
+      baseEach(collection, function(value) {
+        var func = isFunc ? path : ((isProp && value != null) ? value[path] : undefined);
+        result[++index] = func ? func.apply(value, args) : invokePath(value, path, args);
       });
       return result;
-    }
-
-    /**
-     * Creates an array of values by running each element in the collection
-     * through the callback. The callback is bound to `thisArg` and invoked with
-     * three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+    });
+
+    /**
+     * Creates an array of values by running each element in `collection` through
+     * `iteratee`. The `iteratee` is bound to `thisArg` and invoked with three
+     * arguments: (value, index|key, collection).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * Many lodash methods are guarded to work as iteratees for methods like
+     * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
+     *
+     * The guarded methods are:
+     * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`,
+     * `drop`, `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`,
+     * `parseInt`, `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`,
+     * `trimLeft`, `trimRight`, `trunc`, `random`, `range`, `sample`, `some`,
+     * `sum`, `uniq`, and `words`
      *
      * @static
      * @memberOf _
      * @alias collect
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of the results of each `callback` execution.
-     * @example
-     *
-     * _.map([1, 2, 3], function(num) { return num * 3; });
-     * // => [3, 6, 9]
-     *
-     * _.map({ 'one': 1, 'two': 2, 'three': 3 }, function(num) { return num * 3; });
-     * // => [3, 6, 9] (property order is not guaranteed across environments)
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
-     *
-     * // using "_.pluck" callback shorthand
-     * _.map(characters, 'name');
-     * // => ['barney', 'fred']
-     */
-    function map(collection, callback, thisArg) {
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      callback = lodash.createCallback(callback, thisArg, 3);
-      if (typeof length == 'number') {
-        var result = Array(length);
-        while (++index < length) {
-          result[index] = callback(collection[index], index, collection);
-        }
-      } else {
-        result = [];
-        forOwn(collection, function(value, key, collection) {
-          result[++index] = callback(value, key, collection);
-        });
-      }
-      return result;
-    }
-
-    /**
-     * Retrieves the maximum value of a collection. If the collection is empty or
-     * falsey `-Infinity` is returned. If a callback is provided it will be executed
-     * for each value in the collection to generate the criterion by which the value
-     * is ranked. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the maximum value.
-     * @example
-     *
-     * _.max([4, 2, 8, 6]);
-     * // => 8
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the new mapped array.
+     * @example
+     *
+     * function timesThree(n) {
+     *   return n * 3;
+     * }
+     *
+     * _.map([1, 2], timesThree);
+     * // => [3, 6]
+     *
+     * _.map({ 'a': 1, 'b': 2 }, timesThree);
+     * // => [3, 6] (iteration order is not guaranteed)
+     *
+     * var users = [
+     *   { 'user': 'barney' },
+     *   { 'user': 'fred' }
      * ];
      *
-     * _.max(characters, function(chr) { return chr.age; });
-     * // => { 'name': 'fred', 'age': 40 };
-     *
-     * // using "_.pluck" callback shorthand
-     * _.max(characters, 'age');
-     * // => { 'name': 'fred', 'age': 40 };
-     */
-    function max(collection, callback, thisArg) {
-      var computed = -Infinity,
-          result = computed;
-
-      // allows working with functions like `_.map` without using
-      // their `index` argument as a callback
-      if (typeof callback != 'function' && thisArg && thisArg[callback] === collection) {
-        callback = null;
-      }
-      if (callback == null && isArray(collection)) {
-        var index = -1,
-            length = collection.length;
-
-        while (++index < length) {
-          var value = collection[index];
-          if (value > result) {
-            result = value;
-          }
-        }
-      } else {
-        callback = (callback == null && isString(collection))
-          ? charAtCallback
-          : lodash.createCallback(callback, thisArg, 3);
-
-        forEach(collection, function(value, index, collection) {
-          var current = callback(value, index, collection);
-          if (current > computed) {
-            computed = current;
-            result = value;
-          }
-        });
-      }
-      return result;
-    }
-
-    /**
-     * Retrieves the minimum value of a collection. If the collection is empty or
-     * falsey `Infinity` is returned. If a callback is provided it will be executed
-     * for each value in the collection to generate the criterion by which the value
-     * is ranked. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * // using the `_.property` callback shorthand
+     * _.map(users, 'user');
+     * // => ['barney', 'fred']
+     */
+    function map(collection, iteratee, thisArg) {
+      var func = isArray(collection) ? arrayMap : baseMap;
+      iteratee = getCallback(iteratee, thisArg, 3);
+      return func(collection, iteratee);
+    }
+
+    /**
+     * Creates an array of elements split into two groups, the first of which
+     * contains elements `predicate` returns truthy for, while the second of which
+     * contains elements `predicate` returns falsey for. The predicate is bound
+     * to `thisArg` and invoked with three arguments: (value, index|key, collection).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the minimum value.
-     * @example
-     *
-     * _.min([4, 2, 8, 6]);
-     * // => 2
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the array of grouped elements.
+     * @example
+     *
+     * _.partition([1, 2, 3], function(n) {
+     *   return n % 2;
+     * });
+     * // => [[1, 3], [2]]
+     *
+     * _.partition([1.2, 2.3, 3.4], function(n) {
+     *   return this.floor(n) % 2;
+     * }, Math);
+     * // => [[1.2, 3.4], [2.3]]
+     *
+     * var users = [
+     *   { 'user': 'barney',  'age': 36, 'active': false },
+     *   { 'user': 'fred',    'age': 40, 'active': true },
+     *   { 'user': 'pebbles', 'age': 1,  'active': false }
      * ];
      *
-     * _.min(characters, function(chr) { return chr.age; });
-     * // => { 'name': 'barney', 'age': 36 };
-     *
-     * // using "_.pluck" callback shorthand
-     * _.min(characters, 'age');
-     * // => { 'name': 'barney', 'age': 36 };
-     */
-    function min(collection, callback, thisArg) {
-      var computed = Infinity,
-          result = computed;
-
-      // allows working with functions like `_.map` without using
-      // their `index` argument as a callback
-      if (typeof callback != 'function' && thisArg && thisArg[callback] === collection) {
-        callback = null;
-      }
-      if (callback == null && isArray(collection)) {
-        var index = -1,
-            length = collection.length;
-
-        while (++index < length) {
-          var value = collection[index];
-          if (value < result) {
-            result = value;
-          }
-        }
-      } else {
-        callback = (callback == null && isString(collection))
-          ? charAtCallback
-          : lodash.createCallback(callback, thisArg, 3);
-
-        forEach(collection, function(value, index, collection) {
-          var current = callback(value, index, collection);
-          if (current < computed) {
-            computed = current;
-            result = value;
-          }
-        });
-      }
-      return result;
-    }
-
-    /**
-     * Retrieves the value of a specified property from all elements in the collection.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Collections
+     * var mapper = function(array) {
+     *   return _.pluck(array, 'user');
+     * };
+     *
+     * // using the `_.matches` callback shorthand
+     * _.map(_.partition(users, { 'age': 1, 'active': false }), mapper);
+     * // => [['pebbles'], ['barney', 'fred']]
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.map(_.partition(users, 'active', false), mapper);
+     * // => [['barney', 'pebbles'], ['fred']]
+     *
+     * // using the `_.property` callback shorthand
+     * _.map(_.partition(users, 'active'), mapper);
+     * // => [['fred'], ['barney', 'pebbles']]
+     */
+    var partition = createAggregator(function(result, value, key) {
+      result[key ? 0 : 1].push(value);
+    }, function() { return [[], []]; });
+
+    /**
+     * Gets the property value of `path` from all elements in `collection`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {string} property The name of the property to pluck.
-     * @returns {Array} Returns a new array of property values.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * @param {Array|string} path The path of the property to pluck.
+     * @returns {Array} Returns the property values.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 40 }
      * ];
      *
-     * _.pluck(characters, 'name');
+     * _.pluck(users, 'user');
      * // => ['barney', 'fred']
-     */
-    var pluck = map;
-
-    /**
-     * Reduces a collection to a value which is the accumulated result of running
-     * each element in the collection through the callback, where each successive
-     * callback execution consumes the return value of the previous execution. If
-     * `accumulator` is not provided the first element of the collection will be
-     * used as the initial `accumulator` value. The callback is bound to `thisArg`
-     * and invoked with four arguments; (accumulator, value, index|key, collection).
+     *
+     * var userIndex = _.indexBy(users, 'user');
+     * _.pluck(userIndex, 'age');
+     * // => [36, 40] (iteration order is not guaranteed)
+     */
+    function pluck(collection, path) {
+      return map(collection, property(path));
+    }
+
+    /**
+     * Reduces `collection` to a value which is the accumulated result of running
+     * each element in `collection` through `iteratee`, where each successive
+     * invocation is supplied the return value of the previous. If `accumulator`
+     * is not provided the first element of `collection` is used as the initial
+     * value. The `iteratee` is bound to `thisArg` and invoked with four arguments:
+     * (accumulator, value, index|key, collection).
+     *
+     * Many lodash methods are guarded to work as iteratees for methods like
+     * `_.reduce`, `_.reduceRight`, and `_.transform`.
+     *
+     * The guarded methods are:
+     * `assign`, `defaults`, `defaultsDeep`, `includes`, `merge`, `sortByAll`,
+     * and `sortByOrder`
      *
      * @static
      * @memberOf _
      * @alias foldl, inject
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [accumulator] Initial value of the accumulator.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [accumulator] The initial value.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {*} Returns the accumulated value.
      * @example
      *
-     * var sum = _.reduce([1, 2, 3], function(sum, num) {
-     *   return sum + num;
+     * _.reduce([1, 2], function(total, n) {
+     *   return total + n;
      * });
-     * // => 6
-     *
-     * var mapped = _.reduce({ 'a': 1, 'b': 2, 'c': 3 }, function(result, num, key) {
-     *   result[key] = num * 3;
+     * // => 3
+     *
+     * _.reduce({ 'a': 1, 'b': 2 }, function(result, n, key) {
+     *   result[key] = n * 3;
      *   return result;
      * }, {});
-     * // => { 'a': 3, 'b': 6, 'c': 9 }
-     */
-    function reduce(collection, callback, accumulator, thisArg) {
-      if (!collection) return accumulator;
-      var noaccum = arguments.length < 3;
-      callback = lodash.createCallback(callback, thisArg, 4);
-
-      var index = -1,
-          length = collection.length;
-
-      if (typeof length == 'number') {
-        if (noaccum) {
-          accumulator = collection[++index];
-        }
-        while (++index < length) {
-          accumulator = callback(accumulator, collection[index], index, collection);
-        }
-      } else {
-        forOwn(collection, function(value, index, collection) {
-          accumulator = noaccum
-            ? (noaccum = false, value)
-            : callback(accumulator, value, index, collection)
-        });
-      }
-      return accumulator;
-    }
-
-    /**
-     * This method is like `_.reduce` except that it iterates over elements
-     * of a `collection` from right to left.
+     * // => { 'a': 3, 'b': 6 } (iteration order is not guaranteed)
+     */
+    var reduce = createReduce(arrayReduce, baseEach);
+
+    /**
+     * This method is like `_.reduce` except that it iterates over elements of
+     * `collection` from right to left.
      *
      * @static
      * @memberOf _
      * @alias foldr
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [accumulator] Initial value of the accumulator.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [accumulator] The initial value.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {*} Returns the accumulated value.
      * @example
      *
-     * var list = [[0, 1], [2, 3], [4, 5]];
-     * var flat = _.reduceRight(list, function(a, b) { return a.concat(b); }, []);
+     * var array = [[0, 1], [2, 3], [4, 5]];
+     *
+     * _.reduceRight(array, function(flattened, other) {
+     *   return flattened.concat(other);
+     * }, []);
      * // => [4, 5, 2, 3, 0, 1]
      */
-    function reduceRight(collection, callback, accumulator, thisArg) {
-      var noaccum = arguments.length < 3;
-      callback = lodash.createCallback(callback, thisArg, 4);
-      forEachRight(collection, function(value, index, collection) {
-        accumulator = noaccum
-          ? (noaccum = false, value)
-          : callback(accumulator, value, index, collection);
+    var reduceRight = createReduce(arrayReduceRight, baseEachRight);
+
+    /**
+     * The opposite of `_.filter`; this method returns the elements of `collection`
+     * that `predicate` does **not** return truthy for.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the new filtered array.
+     * @example
+     *
+     * _.reject([1, 2, 3, 4], function(n) {
+     *   return n % 2 == 0;
+     * });
+     * // => [1, 3]
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': false },
+     *   { 'user': 'fred',   'age': 40, 'active': true }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.reject(users, { 'age': 40, 'active': true }), 'user');
+     * // => ['barney']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.reject(users, 'active', false), 'user');
+     * // => ['fred']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.reject(users, 'active'), 'user');
+     * // => ['barney']
+     */
+    function reject(collection, predicate, thisArg) {
+      var func = isArray(collection) ? arrayFilter : baseFilter;
+      predicate = getCallback(predicate, thisArg, 3);
+      return func(collection, function(value, index, collection) {
+        return !predicate(value, index, collection);
       });
-      return accumulator;
-    }
-
-    /**
-     * The opposite of `_.filter` this method returns the elements of a
-     * collection that the callback does **not** return truey for.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of elements that failed the callback check.
-     * @example
-     *
-     * var odds = _.reject([1, 2, 3, 4, 5, 6], function(num) { return num % 2 == 0; });
-     * // => [1, 3, 5]
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'blocked': false },
-     *   { 'name': 'fred',   'age': 40, 'blocked': true }
-     * ];
-     *
-     * // using "_.pluck" callback shorthand
-     * _.reject(characters, 'blocked');
-     * // => [{ 'name': 'barney', 'age': 36, 'blocked': false }]
-     *
-     * // using "_.where" callback shorthand
-     * _.reject(characters, { 'age': 36 });
-     * // => [{ 'name': 'fred', 'age': 40, 'blocked': true }]
-     */
-    function reject(collection, callback, thisArg) {
-      callback = lodash.createCallback(callback, thisArg, 3);
-      return filter(collection, function(value, index, collection) {
-        return !callback(value, index, collection);
-      });
-    }
-
-    /**
-     * Retrieves a random element or `n` random elements from a collection.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+    }
+
+    /**
+     * Gets a random element or `n` random elements from a collection.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to sample.
      * @param {number} [n] The number of elements to sample.
-     * @param- {Object} [guard] Allows working with functions like `_.map`
-     *  without using their `index` arguments as `n`.
-     * @returns {Array} Returns the random sample(s) of `collection`.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {*} Returns the random sample(s).
      * @example
      *
      * _.sample([1, 2, 3, 4]);
@@ -3839,1287 +6927,354 @@
      * // => [3, 1]
      */
     function sample(collection, n, guard) {
-      if (collection && typeof collection.length != 'number') {
-        collection = values(collection);
-      }
-      if (n == null || guard) {
-        return collection ? collection[baseRandom(0, collection.length - 1)] : undefined;
-      }
-      var result = shuffle(collection);
-      result.length = nativeMin(nativeMax(0, n), result.length);
+      if (guard ? isIterateeCall(collection, n, guard) : n == null) {
+        collection = toIterable(collection);
+        var length = collection.length;
+        return length > 0 ? collection[baseRandom(0, length - 1)] : undefined;
+      }
+      var index = -1,
+          result = toArray(collection),
+          length = result.length,
+          lastIndex = length - 1;
+
+      n = nativeMin(n < 0 ? 0 : (+n || 0), length);
+      while (++index < n) {
+        var rand = baseRandom(index, lastIndex),
+            value = result[rand];
+
+        result[rand] = result[index];
+        result[index] = value;
+      }
+      result.length = n;
       return result;
     }
 
     /**
-     * Creates an array of shuffled values, using a version of the Fisher-Yates
-     * shuffle. See http://en.wikipedia.org/wiki/Fisher-Yates_shuffle.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * Creates an array of shuffled values, using a version of the
+     * [Fisher-Yates shuffle](https://en.wikipedia.org/wiki/Fisher-Yates_shuffle).
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to shuffle.
-     * @returns {Array} Returns a new shuffled collection.
-     * @example
-     *
-     * _.shuffle([1, 2, 3, 4, 5, 6]);
-     * // => [4, 1, 6, 3, 5, 2]
+     * @returns {Array} Returns the new shuffled array.
+     * @example
+     *
+     * _.shuffle([1, 2, 3, 4]);
+     * // => [4, 1, 3, 2]
      */
     function shuffle(collection) {
-      var index = -1,
-          length = collection ? collection.length : 0,
-          result = Array(typeof length == 'number' ? length : 0);
-
-      forEach(collection, function(value) {
-        var rand = baseRandom(0, ++index);
-        result[index] = result[rand];
-        result[rand] = value;
-      });
-      return result;
-    }
-
-    /**
-     * Gets the size of the `collection` by returning `collection.length` for arrays
-     * and array-like objects or the number of own enumerable properties for objects.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+      return sample(collection, POSITIVE_INFINITY);
+    }
+
+    /**
+     * Gets the size of `collection` by returning its length for array-like
+     * values or the number of own enumerable properties for objects.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to inspect.
-     * @returns {number} Returns `collection.length` or number of own enumerable properties.
-     * @example
-     *
-     * _.size([1, 2]);
+     * @returns {number} Returns the size of `collection`.
+     * @example
+     *
+     * _.size([1, 2, 3]);
+     * // => 3
+     *
+     * _.size({ 'a': 1, 'b': 2 });
      * // => 2
      *
-     * _.size({ 'one': 1, 'two': 2, 'three': 3 });
-     * // => 3
-     *
      * _.size('pebbles');
      * // => 7
      */
     function size(collection) {
-      var length = collection ? collection.length : 0;
-      return typeof length == 'number' ? length : keys(collection).length;
-    }
-
-    /**
-     * Checks if the callback returns a truey value for **any** element of a
-     * collection. The function returns as soon as it finds a passing value and
-     * does not iterate over the entire collection. The callback is bound to
-     * `thisArg` and invoked with three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+      var length = collection ? getLength(collection) : 0;
+      return isLength(length) ? length : keys(collection).length;
+    }
+
+    /**
+     * Checks if `predicate` returns truthy for **any** element of `collection`.
+     * The function returns as soon as it finds a passing value and does not iterate
+     * over the entire collection. The predicate is bound to `thisArg` and invoked
+     * with three arguments: (value, index|key, collection).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
      *
      * @static
      * @memberOf _
      * @alias any
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {boolean} Returns `true` if any element passed the callback check,
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {boolean} Returns `true` if any element passes the predicate check,
      *  else `false`.
      * @example
      *
      * _.some([null, 0, 'yes', false], Boolean);
      * // => true
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'blocked': false },
-     *   { 'name': 'fred',   'age': 40, 'blocked': true }
+     * var users = [
+     *   { 'user': 'barney', 'active': true },
+     *   { 'user': 'fred',   'active': false }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.some(characters, 'blocked');
-     * // => true
-     *
-     * // using "_.where" callback shorthand
-     * _.some(characters, { 'age': 1 });
+     * // using the `_.matches` callback shorthand
+     * _.some(users, { 'user': 'barney', 'active': false });
      * // => false
-     */
-    function some(collection, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      if (typeof length == 'number') {
-        while (++index < length) {
-          if ((result = callback(collection[index], index, collection))) {
-            break;
-          }
-        }
-      } else {
-        forOwn(collection, function(value, index, collection) {
-          return !(result = callback(value, index, collection));
-        });
-      }
-      return !!result;
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.some(users, 'active', false);
+     * // => true
+     *
+     * // using the `_.property` callback shorthand
+     * _.some(users, 'active');
+     * // => true
+     */
+    function some(collection, predicate, thisArg) {
+      var func = isArray(collection) ? arraySome : baseSome;
+      if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
+        predicate = undefined;
+      }
+      if (typeof predicate != 'function' || thisArg !== undefined) {
+        predicate = getCallback(predicate, thisArg, 3);
+      }
+      return func(collection, predicate);
     }
 
     /**
      * Creates an array of elements, sorted in ascending order by the results of
-     * running each element in a collection through the callback. This method
-     * performs a stable sort, that is, it will preserve the original sort order
-     * of equal elements. The callback is bound to `thisArg` and invoked with
-     * three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an array of property names is provided for `callback` the collection
-     * will be sorted by each property value.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * running each element in a collection through `iteratee`. This method performs
+     * a stable sort, that is, it preserves the original sort order of equal elements.
+     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
+     * (value, index|key, collection).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Array|Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of sorted elements.
-     * @example
-     *
-     * _.sortBy([1, 2, 3], function(num) { return Math.sin(num); });
-     * // => [3, 1, 2]
-     *
-     * _.sortBy([1, 2, 3], function(num) { return this.sin(num); }, Math);
-     * // => [3, 1, 2]
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36 },
-     *   { 'name': 'fred',    'age': 40 },
-     *   { 'name': 'barney',  'age': 26 },
-     *   { 'name': 'fred',    'age': 30 }
-     * ];
-     *
-     * // using "_.pluck" callback shorthand
-     * _.map(_.sortBy(characters, 'age'), _.values);
-     * // => [['barney', 26], ['fred', 30], ['barney', 36], ['fred', 40]]
-     *
-     * // sorting by multiple properties
-     * _.map(_.sortBy(characters, ['name', 'age']), _.values);
-     * // = > [['barney', 26], ['barney', 36], ['fred', 30], ['fred', 40]]
-     */
-    function sortBy(collection, callback, thisArg) {
-      var index = -1,
-          isArr = isArray(callback),
-          length = collection ? collection.length : 0,
-          result = Array(typeof length == 'number' ? length : 0);
-
-      if (!isArr) {
-        callback = lodash.createCallback(callback, thisArg, 3);
-      }
-      forEach(collection, function(value, key, collection) {
-        var object = result[++index] = getObject();
-        if (isArr) {
-          object.criteria = map(callback, function(key) { return value[key]; });
-        } else {
-          (object.criteria = getArray())[0] = callback(value, key, collection);
-        }
-        object.index = index;
-        object.value = value;
-      });
-
-      length = result.length;
-      result.sort(compareAscending);
-      while (length--) {
-        var object = result[length];
-        result[length] = object.value;
-        if (!isArr) {
-          releaseArray(object.criteria);
-        }
-        releaseObject(object);
-      }
-      return result;
-    }
-
-    /**
-     * Converts the `collection` to an array.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to convert.
-     * @returns {Array} Returns the new converted array.
-     * @example
-     *
-     * (function() { return _.toArray(arguments).slice(1); })(1, 2, 3, 4);
-     * // => [2, 3, 4]
-     */
-    function toArray(collection) {
-      if (collection && typeof collection.length == 'number') {
-        return slice(collection);
-      }
-      return values(collection);
-    }
-
-    /**
-     * Performs a deep comparison of each element in a `collection` to the given
-     * `properties` object, returning an array of all elements that have equivalent
-     * property values.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Object} props The object of property values to filter by.
-     * @returns {Array} Returns a new array of elements that have the given properties.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'pets': ['hoppy'] },
-     *   { 'name': 'fred',   'age': 40, 'pets': ['baby puss', 'dino'] }
-     * ];
-     *
-     * _.where(characters, { 'age': 36 });
-     * // => [{ 'name': 'barney', 'age': 36, 'pets': ['hoppy'] }]
-     *
-     * _.where(characters, { 'pets': ['dino'] });
-     * // => [{ 'name': 'fred', 'age': 40, 'pets': ['baby puss', 'dino'] }]
-     */
-    var where = filter;
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates an array with all falsey values removed. The values `false`, `null`,
-     * `0`, `""`, `undefined`, and `NaN` are all falsey.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to compact.
-     * @returns {Array} Returns a new array of filtered values.
-     * @example
-     *
-     * _.compact([0, 1, false, 2, '', 3]);
-     * // => [1, 2, 3]
-     */
-    function compact(array) {
-      var index = -1,
-          length = array ? array.length : 0,
-          result = [];
-
-      while (++index < length) {
-        var value = array[index];
-        if (value) {
-          result.push(value);
-        }
-      }
-      return result;
-    }
-
-    /**
-     * Creates an array excluding all values of the provided arrays using strict
-     * equality for comparisons, i.e. `===`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to process.
-     * @param {...Array} [values] The arrays of values to exclude.
-     * @returns {Array} Returns a new array of filtered values.
-     * @example
-     *
-     * _.difference([1, 2, 3, 4, 5], [5, 2, 10]);
-     * // => [1, 3, 4]
-     */
-    function difference(array) {
-      return baseDifference(array, baseFlatten(arguments, true, true, 1));
-    }
-
-    /**
-     * This method is like `_.find` except that it returns the index of the first
-     * element that passes the callback check, instead of the element itself.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {number} Returns the index of the found element, else `-1`.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36, 'blocked': false },
-     *   { 'name': 'fred',    'age': 40, 'blocked': true },
-     *   { 'name': 'pebbles', 'age': 1,  'blocked': false }
-     * ];
-     *
-     * _.findIndex(characters, function(chr) {
-     *   return chr.age < 20;
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the new sorted array.
+     * @example
+     *
+     * _.sortBy([1, 2, 3], function(n) {
+     *   return Math.sin(n);
      * });
-     * // => 2
-     *
-     * // using "_.where" callback shorthand
-     * _.findIndex(characters, { 'age': 36 });
-     * // => 0
-     *
-     * // using "_.pluck" callback shorthand
-     * _.findIndex(characters, 'blocked');
-     * // => 1
-     */
-    function findIndex(array, callback, thisArg) {
-      var index = -1,
-          length = array ? array.length : 0;
-
-      callback = lodash.createCallback(callback, thisArg, 3);
-      while (++index < length) {
-        if (callback(array[index], index, array)) {
-          return index;
-        }
-      }
-      return -1;
-    }
-
-    /**
-     * This method is like `_.findIndex` except that it iterates over elements
-     * of a `collection` from right to left.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {number} Returns the index of the found element, else `-1`.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36, 'blocked': true },
-     *   { 'name': 'fred',    'age': 40, 'blocked': false },
-     *   { 'name': 'pebbles', 'age': 1,  'blocked': true }
-     * ];
-     *
-     * _.findLastIndex(characters, function(chr) {
-     *   return chr.age > 30;
-     * });
-     * // => 1
-     *
-     * // using "_.where" callback shorthand
-     * _.findLastIndex(characters, { 'age': 36 });
-     * // => 0
-     *
-     * // using "_.pluck" callback shorthand
-     * _.findLastIndex(characters, 'blocked');
-     * // => 2
-     */
-    function findLastIndex(array, callback, thisArg) {
-      var length = array ? array.length : 0;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      while (length--) {
-        if (callback(array[length], length, array)) {
-          return length;
-        }
-      }
-      return -1;
-    }
-
-    /**
-     * Gets the first element or first `n` elements of an array. If a callback
-     * is provided elements at the beginning of the array are returned as long
-     * as the callback returns truey. The callback is bound to `thisArg` and
-     * invoked with three arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @alias head, take
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback] The function called
-     *  per element or the number of elements to return. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the first element(s) of `array`.
-     * @example
-     *
-     * _.first([1, 2, 3]);
-     * // => 1
-     *
-     * _.first([1, 2, 3], 2);
-     * // => [1, 2]
-     *
-     * _.first([1, 2, 3], function(num) {
-     *   return num < 3;
-     * });
-     * // => [1, 2]
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': false, 'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true,  'employer': 'na' }
+     * // => [3, 1, 2]
+     *
+     * _.sortBy([1, 2, 3], function(n) {
+     *   return this.sin(n);
+     * }, Math);
+     * // => [3, 1, 2]
+     *
+     * var users = [
+     *   { 'user': 'fred' },
+     *   { 'user': 'pebbles' },
+     *   { 'user': 'barney' }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.first(characters, 'blocked');
-     * // => [{ 'name': 'barney', 'blocked': true, 'employer': 'slate' }]
-     *
-     * // using "_.where" callback shorthand
-     * _.pluck(_.first(characters, { 'employer': 'slate' }), 'name');
-     * // => ['barney', 'fred']
-     */
-    function first(array, callback, thisArg) {
-      var n = 0,
-          length = array ? array.length : 0;
-
-      if (typeof callback != 'number' && callback != null) {
-        var index = -1;
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (++index < length && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = callback;
-        if (n == null || thisArg) {
-          return array ? array[0] : undefined;
-        }
-      }
-      return slice(array, 0, nativeMin(nativeMax(0, n), length));
-    }
-
-    /**
-     * Flattens a nested array (the nesting can be to any depth). If `isShallow`
-     * is truey, the array will only be flattened a single level. If a callback
-     * is provided each element of the array is passed through the callback before
-     * flattening. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to flatten.
-     * @param {boolean} [isShallow=false] A flag to restrict flattening to a single level.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new flattened array.
-     * @example
-     *
-     * _.flatten([1, [2], [3, [[4]]]]);
-     * // => [1, 2, 3, 4];
-     *
-     * _.flatten([1, [2], [3, [[4]]]], true);
-     * // => [1, 2, 3, [[4]]];
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 30, 'pets': ['hoppy'] },
-     *   { 'name': 'fred',   'age': 40, 'pets': ['baby puss', 'dino'] }
-     * ];
-     *
-     * // using "_.pluck" callback shorthand
-     * _.flatten(characters, 'pets');
-     * // => ['hoppy', 'baby puss', 'dino']
-     */
-    function flatten(array, isShallow, callback, thisArg) {
-      // juggle arguments
-      if (typeof isShallow != 'boolean' && isShallow != null) {
-        thisArg = callback;
-        callback = (typeof isShallow != 'function' && thisArg && thisArg[isShallow] === array) ? null : isShallow;
-        isShallow = false;
-      }
-      if (callback != null) {
-        array = map(array, callback, thisArg);
-      }
-      return baseFlatten(array, isShallow);
-    }
-
-    /**
-     * Gets the index at which the first occurrence of `value` is found using
-     * strict equality for comparisons, i.e. `===`. If the array is already sorted
-     * providing `true` for `fromIndex` will run a faster binary search.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {*} value The value to search for.
-     * @param {boolean|number} [fromIndex=0] The index to search from or `true`
-     *  to perform a binary search on a sorted array.
-     * @returns {number} Returns the index of the matched value or `-1`.
-     * @example
-     *
-     * _.indexOf([1, 2, 3, 1, 2, 3], 2);
-     * // => 1
-     *
-     * _.indexOf([1, 2, 3, 1, 2, 3], 2, 3);
-     * // => 4
-     *
-     * _.indexOf([1, 1, 2, 2, 3, 3], 2, true);
-     * // => 2
-     */
-    function indexOf(array, value, fromIndex) {
-      if (typeof fromIndex == 'number') {
-        var length = array ? array.length : 0;
-        fromIndex = (fromIndex < 0 ? nativeMax(0, length + fromIndex) : fromIndex || 0);
-      } else if (fromIndex) {
-        var index = sortedIndex(array, value);
-        return array[index] === value ? index : -1;
-      }
-      return baseIndexOf(array, value, fromIndex);
-    }
-
-    /**
-     * Gets all but the last element or last `n` elements of an array. If a
-     * callback is provided elements at the end of the array are excluded from
-     * the result as long as the callback returns truey. The callback is bound
-     * to `thisArg` and invoked with three arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback=1] The function called
-     *  per element or the number of elements to exclude. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a slice of `array`.
-     * @example
-     *
-     * _.initial([1, 2, 3]);
-     * // => [1, 2]
-     *
-     * _.initial([1, 2, 3], 2);
-     * // => [1]
-     *
-     * _.initial([1, 2, 3], function(num) {
-     *   return num > 1;
-     * });
-     * // => [1]
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': false, 'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true,  'employer': 'na' }
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.sortBy(users, 'user'), 'user');
+     * // => ['barney', 'fred', 'pebbles']
+     */
+    function sortBy(collection, iteratee, thisArg) {
+      if (collection == null) {
+        return [];
+      }
+      if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
+        iteratee = undefined;
+      }
+      var index = -1;
+      iteratee = getCallback(iteratee, thisArg, 3);
+
+      var result = baseMap(collection, function(value, key, collection) {
+        return { 'criteria': iteratee(value, key, collection), 'index': ++index, 'value': value };
+      });
+      return baseSortBy(result, compareAscending);
+    }
+
+    /**
+     * This method is like `_.sortBy` except that it can sort by multiple iteratees
+     * or property names.
+     *
+     * If a property name is provided for an iteratee the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If an object is provided for an iteratee the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {...(Function|Function[]|Object|Object[]|string|string[])} iteratees
+     *  The iteratees to sort by, specified as individual values or arrays of values.
+     * @returns {Array} Returns the new sorted array.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'fred',   'age': 48 },
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 42 },
+     *   { 'user': 'barney', 'age': 34 }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.initial(characters, 'blocked');
-     * // => [{ 'name': 'barney',  'blocked': false, 'employer': 'slate' }]
-     *
-     * // using "_.where" callback shorthand
-     * _.pluck(_.initial(characters, { 'employer': 'na' }), 'name');
-     * // => ['barney', 'fred']
-     */
-    function initial(array, callback, thisArg) {
-      var n = 0,
-          length = array ? array.length : 0;
-
-      if (typeof callback != 'number' && callback != null) {
-        var index = length;
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (index-- && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = (callback == null || thisArg) ? 1 : callback || n;
-      }
-      return slice(array, 0, nativeMin(nativeMax(0, length - n), length));
-    }
-
-    /**
-     * Creates an array of unique values present in all provided arrays using
-     * strict equality for comparisons, i.e. `===`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {...Array} [array] The arrays to inspect.
-     * @returns {Array} Returns an array of shared values.
-     * @example
-     *
-     * _.intersection([1, 2, 3], [5, 2, 1, 4], [2, 1]);
-     * // => [1, 2]
-     */
-    function intersection() {
-      var args = [],
-          argsIndex = -1,
-          argsLength = arguments.length,
-          caches = getArray(),
-          indexOf = getIndexOf(),
-          trustIndexOf = indexOf === baseIndexOf,
-          seen = getArray();
-
-      while (++argsIndex < argsLength) {
-        var value = arguments[argsIndex];
-        if (isArray(value) || isArguments(value)) {
-          args.push(value);
-          caches.push(trustIndexOf && value.length >= largeArraySize &&
-            createCache(argsIndex ? args[argsIndex] : seen));
-        }
-      }
-      var array = args[0],
-          index = -1,
-          length = array ? array.length : 0,
-          result = [];
-
-      outer:
-      while (++index < length) {
-        var cache = caches[0];
-        value = array[index];
-
-        if ((cache ? cacheIndexOf(cache, value) : indexOf(seen, value)) < 0) {
-          argsIndex = argsLength;
-          (cache || seen).push(value);
-          while (--argsIndex) {
-            cache = caches[argsIndex];
-            if ((cache ? cacheIndexOf(cache, value) : indexOf(args[argsIndex], value)) < 0) {
-              continue outer;
-            }
-          }
-          result.push(value);
-        }
-      }
-      while (argsLength--) {
-        cache = caches[argsLength];
-        if (cache) {
-          releaseObject(cache);
-        }
-      }
-      releaseArray(caches);
-      releaseArray(seen);
-      return result;
-    }
-
-    /**
-     * Gets the last element or last `n` elements of an array. If a callback is
-     * provided elements at the end of the array are returned as long as the
-     * callback returns truey. The callback is bound to `thisArg` and invoked
-     * with three arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback] The function called
-     *  per element or the number of elements to return. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the last element(s) of `array`.
-     * @example
-     *
-     * _.last([1, 2, 3]);
-     * // => 3
-     *
-     * _.last([1, 2, 3], 2);
-     * // => [2, 3]
-     *
-     * _.last([1, 2, 3], function(num) {
-     *   return num > 1;
-     * });
-     * // => [2, 3]
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': false, 'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true,  'employer': 'na' }
+     * _.map(_.sortByAll(users, ['user', 'age']), _.values);
+     * // => [['barney', 34], ['barney', 36], ['fred', 42], ['fred', 48]]
+     *
+     * _.map(_.sortByAll(users, 'user', function(chr) {
+     *   return Math.floor(chr.age / 10);
+     * }), _.values);
+     * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
+     */
+    var sortByAll = restParam(function(collection, iteratees) {
+      if (collection == null) {
+        return [];
+      }
+      var guard = iteratees[2];
+      if (guard && isIterateeCall(iteratees[0], iteratees[1], guard)) {
+        iteratees.length = 1;
+      }
+      return baseSortByOrder(collection, baseFlatten(iteratees), []);
+    });
+
+    /**
+     * This method is like `_.sortByAll` except that it allows specifying the
+     * sort orders of the iteratees to sort by. If `orders` is unspecified, all
+     * values are sorted in ascending order. Otherwise, a value is sorted in
+     * ascending order if its corresponding order is "asc", and descending if "desc".
+     *
+     * If a property name is provided for an iteratee the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If an object is provided for an iteratee the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
+     * @param {boolean[]} [orders] The sort orders of `iteratees`.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
+     * @returns {Array} Returns the new sorted array.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'fred',   'age': 48 },
+     *   { 'user': 'barney', 'age': 34 },
+     *   { 'user': 'fred',   'age': 42 },
+     *   { 'user': 'barney', 'age': 36 }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.pluck(_.last(characters, 'blocked'), 'name');
-     * // => ['fred', 'pebbles']
-     *
-     * // using "_.where" callback shorthand
-     * _.last(characters, { 'employer': 'na' });
-     * // => [{ 'name': 'pebbles', 'blocked': true, 'employer': 'na' }]
-     */
-    function last(array, callback, thisArg) {
-      var n = 0,
-          length = array ? array.length : 0;
-
-      if (typeof callback != 'number' && callback != null) {
-        var index = length;
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (index-- && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = callback;
-        if (n == null || thisArg) {
-          return array ? array[length - 1] : undefined;
-        }
-      }
-      return slice(array, nativeMax(0, length - n));
-    }
-
-    /**
-     * Gets the index at which the last occurrence of `value` is found using strict
-     * equality for comparisons, i.e. `===`. If `fromIndex` is negative, it is used
-     * as the offset from the end of the collection.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {*} value The value to search for.
-     * @param {number} [fromIndex=array.length-1] The index to search from.
-     * @returns {number} Returns the index of the matched value or `-1`.
-     * @example
-     *
-     * _.lastIndexOf([1, 2, 3, 1, 2, 3], 2);
-     * // => 4
-     *
-     * _.lastIndexOf([1, 2, 3, 1, 2, 3], 2, 3);
-     * // => 1
-     */
-    function lastIndexOf(array, value, fromIndex) {
-      var index = array ? array.length : 0;
-      if (typeof fromIndex == 'number') {
-        index = (fromIndex < 0 ? nativeMax(0, index + fromIndex) : nativeMin(fromIndex, index - 1)) + 1;
-      }
-      while (index--) {
-        if (array[index] === value) {
-          return index;
-        }
-      }
-      return -1;
-    }
-
-    /**
-     * Removes all provided values from the given array using strict equality for
-     * comparisons, i.e. `===`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to modify.
-     * @param {...*} [value] The values to remove.
-     * @returns {Array} Returns `array`.
-     * @example
-     *
-     * var array = [1, 2, 3, 1, 2, 3];
-     * _.pull(array, 2, 3);
-     * console.log(array);
-     * // => [1, 1]
-     */
-    function pull(array) {
-      var args = arguments,
-          argsIndex = 0,
-          argsLength = args.length,
-          length = array ? array.length : 0;
-
-      while (++argsIndex < argsLength) {
-        var index = -1,
-            value = args[argsIndex];
-        while (++index < length) {
-          if (array[index] === value) {
-            splice.call(array, index--, 1);
-            length--;
-          }
-        }
-      }
-      return array;
-    }
-
-    /**
-     * Creates an array of numbers (positive and/or negative) progressing from
-     * `start` up to but not including `end`. If `start` is less than `stop` a
-     * zero-length range is created unless a negative `step` is specified.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {number} [start=0] The start of the range.
-     * @param {number} end The end of the range.
-     * @param {number} [step=1] The value to increment or decrement by.
-     * @returns {Array} Returns a new range array.
-     * @example
-     *
-     * _.range(4);
-     * // => [0, 1, 2, 3]
-     *
-     * _.range(1, 5);
-     * // => [1, 2, 3, 4]
-     *
-     * _.range(0, 20, 5);
-     * // => [0, 5, 10, 15]
-     *
-     * _.range(0, -4, -1);
-     * // => [0, -1, -2, -3]
-     *
-     * _.range(1, 4, 0);
-     * // => [1, 1, 1]
-     *
-     * _.range(0);
-     * // => []
-     */
-    function range(start, end, step) {
-      start = +start || 0;
-      step = typeof step == 'number' ? step : (+step || 1);
-
-      if (end == null) {
-        end = start;
-        start = 0;
-      }
-      // use `Array(length)` so engines like Chakra and V8 avoid slower modes
-      // http://youtu.be/XAqIpGU8ZZk#t=17m25s
-      var index = -1,
-          length = nativeMax(0, ceil((end - start) / (step || 1))),
-          result = Array(length);
-
-      while (++index < length) {
-        result[index] = start;
-        start += step;
-      }
-      return result;
-    }
-
-    /**
-     * Removes all elements from an array that the callback returns truey for
-     * and returns an array of removed elements. The callback is bound to `thisArg`
-     * and invoked with three arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to modify.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of removed elements.
-     * @example
-     *
-     * var array = [1, 2, 3, 4, 5, 6];
-     * var evens = _.remove(array, function(num) { return num % 2 == 0; });
-     *
-     * console.log(array);
-     * // => [1, 3, 5]
-     *
-     * console.log(evens);
-     * // => [2, 4, 6]
-     */
-    function remove(array, callback, thisArg) {
-      var index = -1,
-          length = array ? array.length : 0,
-          result = [];
-
-      callback = lodash.createCallback(callback, thisArg, 3);
-      while (++index < length) {
-        var value = array[index];
-        if (callback(value, index, array)) {
-          result.push(value);
-          splice.call(array, index--, 1);
-          length--;
-        }
-      }
-      return result;
-    }
-
-    /**
-     * The opposite of `_.initial` this method gets all but the first element or
-     * first `n` elements of an array. If a callback function is provided elements
-     * at the beginning of the array are excluded from the result as long as the
-     * callback returns truey. The callback is bound to `thisArg` and invoked
-     * with three arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @alias drop, tail
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback=1] The function called
-     *  per element or the number of elements to exclude. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a slice of `array`.
-     * @example
-     *
-     * _.rest([1, 2, 3]);
-     * // => [2, 3]
-     *
-     * _.rest([1, 2, 3], 2);
-     * // => [3]
-     *
-     * _.rest([1, 2, 3], function(num) {
-     *   return num < 3;
-     * });
-     * // => [3]
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': false,  'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true, 'employer': 'na' }
+     * // sort by `user` in ascending order and by `age` in descending order
+     * _.map(_.sortByOrder(users, ['user', 'age'], ['asc', 'desc']), _.values);
+     * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
+     */
+    function sortByOrder(collection, iteratees, orders, guard) {
+      if (collection == null) {
+        return [];
+      }
+      if (guard && isIterateeCall(iteratees, orders, guard)) {
+        orders = undefined;
+      }
+      if (!isArray(iteratees)) {
+        iteratees = iteratees == null ? [] : [iteratees];
+      }
+      if (!isArray(orders)) {
+        orders = orders == null ? [] : [orders];
+      }
+      return baseSortByOrder(collection, iteratees, orders);
+    }
+
+    /**
+     * Performs a deep comparison between each element in `collection` and the
+     * source object, returning an array of all elements that have equivalent
+     * property values.
+     *
+     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
+     * numbers, `Object` objects, regexes, and strings. Objects are compared by
+     * their own, not inherited, enumerable properties. For comparing a single
+     * own or inherited property value see `_.matchesProperty`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {Object} source The object of property values to match.
+     * @returns {Array} Returns the new filtered array.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': false, 'pets': ['hoppy'] },
+     *   { 'user': 'fred',   'age': 40, 'active': true, 'pets': ['baby puss', 'dino'] }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.pluck(_.rest(characters, 'blocked'), 'name');
-     * // => ['fred', 'pebbles']
-     *
-     * // using "_.where" callback shorthand
-     * _.rest(characters, { 'employer': 'slate' });
-     * // => [{ 'name': 'pebbles', 'blocked': true, 'employer': 'na' }]
-     */
-    function rest(array, callback, thisArg) {
-      if (typeof callback != 'number' && callback != null) {
-        var n = 0,
-            index = -1,
-            length = array ? array.length : 0;
-
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (++index < length && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = (callback == null || thisArg) ? 1 : nativeMax(0, callback);
-      }
-      return slice(array, n);
-    }
-
-    /**
-     * Uses a binary search to determine the smallest index at which a value
-     * should be inserted into a given sorted array in order to maintain the sort
-     * order of the array. If a callback is provided it will be executed for
-     * `value` and each element of `array` to compute their sort ranking. The
-     * callback is bound to `thisArg` and invoked with one argument; (value).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to inspect.
-     * @param {*} value The value to evaluate.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {number} Returns the index at which `value` should be inserted
-     *  into `array`.
-     * @example
-     *
-     * _.sortedIndex([20, 30, 50], 40);
-     * // => 2
-     *
-     * // using "_.pluck" callback shorthand
-     * _.sortedIndex([{ 'x': 20 }, { 'x': 30 }, { 'x': 50 }], { 'x': 40 }, 'x');
-     * // => 2
-     *
-     * var dict = {
-     *   'wordToNumber': { 'twenty': 20, 'thirty': 30, 'fourty': 40, 'fifty': 50 }
-     * };
-     *
-     * _.sortedIndex(['twenty', 'thirty', 'fifty'], 'fourty', function(word) {
-     *   return dict.wordToNumber[word];
-     * });
-     * // => 2
-     *
-     * _.sortedIndex(['twenty', 'thirty', 'fifty'], 'fourty', function(word) {
-     *   return this.wordToNumber[word];
-     * }, dict);
-     * // => 2
-     */
-    function sortedIndex(array, value, callback, thisArg) {
-      var low = 0,
-          high = array ? array.length : low;
-
-      // explicitly reference `identity` for better inlining in Firefox
-      callback = callback ? lodash.createCallback(callback, thisArg, 1) : identity;
-      value = callback(value);
-
-      while (low < high) {
-        var mid = (low + high) >>> 1;
-        (callback(array[mid]) < value)
-          ? low = mid + 1
-          : high = mid;
-      }
-      return low;
-    }
-
-    /**
-     * Creates an array of unique values, in order, of the provided arrays using
-     * strict equality for comparisons, i.e. `===`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {...Array} [array] The arrays to inspect.
-     * @returns {Array} Returns an array of combined values.
-     * @example
-     *
-     * _.union([1, 2, 3], [5, 2, 1, 4], [2, 1]);
-     * // => [1, 2, 3, 5, 4]
-     */
-    function union() {
-      return baseUniq(baseFlatten(arguments, true, true));
-    }
-
-    /**
-     * Creates a duplicate-value-free version of an array using strict equality
-     * for comparisons, i.e. `===`. If the array is sorted, providing
-     * `true` for `isSorted` will use a faster algorithm. If a callback is provided
-     * each element of `array` is passed through the callback before uniqueness
-     * is computed. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @alias unique
-     * @category Arrays
-     * @param {Array} array The array to process.
-     * @param {boolean} [isSorted=false] A flag to indicate that `array` is sorted.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a duplicate-value-free array.
-     * @example
-     *
-     * _.uniq([1, 2, 1, 3, 1]);
-     * // => [1, 2, 3]
-     *
-     * _.uniq([1, 1, 2, 2, 3], true);
-     * // => [1, 2, 3]
-     *
-     * _.uniq(['A', 'b', 'C', 'a', 'B', 'c'], function(letter) { return letter.toLowerCase(); });
-     * // => ['A', 'b', 'C']
-     *
-     * _.uniq([1, 2.5, 3, 1.5, 2, 3.5], function(num) { return this.floor(num); }, Math);
-     * // => [1, 2.5, 3]
-     *
-     * // using "_.pluck" callback shorthand
-     * _.uniq([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
-     * // => [{ 'x': 1 }, { 'x': 2 }]
-     */
-    function uniq(array, isSorted, callback, thisArg) {
-      // juggle arguments
-      if (typeof isSorted != 'boolean' && isSorted != null) {
-        thisArg = callback;
-        callback = (typeof isSorted != 'function' && thisArg && thisArg[isSorted] === array) ? null : isSorted;
-        isSorted = false;
-      }
-      if (callback != null) {
-        callback = lodash.createCallback(callback, thisArg, 3);
-      }
-      return baseUniq(array, isSorted, callback);
-    }
-
-    /**
-     * Creates an array excluding all provided values using strict equality for
-     * comparisons, i.e. `===`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to filter.
-     * @param {...*} [value] The values to exclude.
-     * @returns {Array} Returns a new array of filtered values.
-     * @example
-     *
-     * _.without([1, 2, 1, 0, 3, 1, 4], 0, 1);
-     * // => [2, 3, 4]
-     */
-    function without(array) {
-      return baseDifference(array, slice(arguments, 1));
-    }
-
-    /**
-     * Creates an array that is the symmetric difference of the provided arrays.
-     * See http://en.wikipedia.org/wiki/Symmetric_difference.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {...Array} [array] The arrays to inspect.
-     * @returns {Array} Returns an array of values.
-     * @example
-     *
-     * _.xor([1, 2, 3], [5, 2, 1, 4]);
-     * // => [3, 5, 4]
-     *
-     * _.xor([1, 2, 5], [2, 3, 5], [3, 4, 5]);
-     * // => [1, 4, 5]
-     */
-    function xor() {
-      var index = -1,
-          length = arguments.length;
-
-      while (++index < length) {
-        var array = arguments[index];
-        if (isArray(array) || isArguments(array)) {
-          var result = result
-            ? baseUniq(baseDifference(result, array).concat(baseDifference(array, result)))
-            : array;
-        }
-      }
-      return result || [];
-    }
-
-    /**
-     * Creates an array of grouped elements, the first of which contains the first
-     * elements of the given arrays, the second of which contains the second
-     * elements of the given arrays, and so on.
-     *
-     * @static
-     * @memberOf _
-     * @alias unzip
-     * @category Arrays
-     * @param {...Array} [array] Arrays to process.
-     * @returns {Array} Returns a new array of grouped elements.
-     * @example
-     *
-     * _.zip(['fred', 'barney'], [30, 40], [true, false]);
-     * // => [['fred', 30, true], ['barney', 40, false]]
-     */
-    function zip() {
-      var array = arguments.length > 1 ? arguments : arguments[0],
-          index = -1,
-          length = array ? max(pluck(array, 'length')) : 0,
-          result = Array(length < 0 ? 0 : length);
-
-      while (++index < length) {
-        result[index] = pluck(array, index);
-      }
-      return result;
-    }
-
-    /**
-     * Creates an object composed from arrays of `keys` and `values`. Provide
-     * either a single two dimensional array, i.e. `[[key1, value1], [key2, value2]]`
-     * or two arrays, one of `keys` and one of corresponding `values`.
-     *
-     * @static
-     * @memberOf _
-     * @alias object
-     * @category Arrays
-     * @param {Array} keys The array of keys.
-     * @param {Array} [values=[]] The array of values.
-     * @returns {Object} Returns an object composed of the given keys and
-     *  corresponding values.
-     * @example
-     *
-     * _.zipObject(['fred', 'barney'], [30, 40]);
-     * // => { 'fred': 30, 'barney': 40 }
-     */
-    function zipObject(keys, values) {
-      var index = -1,
-          length = keys ? keys.length : 0,
-          result = {};
-
-      if (!values && length && !isArray(keys[0])) {
-        values = [];
-      }
-      while (++index < length) {
-        var key = keys[index];
-        if (values) {
-          result[key] = values[index];
-        } else if (key) {
-          result[key[0]] = key[1];
-        }
-      }
-      return result;
-    }
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates a function that executes `func`, with  the `this` binding and
-     * arguments of the created function, only after being called `n` times.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
-     * @param {number} n The number of times the function must be called before
-     *  `func` is executed.
+     * _.pluck(_.where(users, { 'age': 36, 'active': false }), 'user');
+     * // => ['barney']
+     *
+     * _.pluck(_.where(users, { 'pets': ['dino'] }), 'user');
+     * // => ['fred']
+     */
+    function where(collection, source) {
+      return filter(collection, baseMatches(source));
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Gets the number of milliseconds that have elapsed since the Unix epoch
+     * (1 January 1970 00:00:00 UTC).
+     *
+     * @static
+     * @memberOf _
+     * @category Date
+     * @example
+     *
+     * _.defer(function(stamp) {
+     *   console.log(_.now() - stamp);
+     * }, _.now());
+     * // => logs the number of milliseconds it took for the deferred function to be invoked
+     */
+    var now = nativeNow || function() {
+      return new Date().getTime();
+    };
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * The opposite of `_.before`; this method creates a function that invokes
+     * `func` once it's called `n` or more times.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {number} n The number of calls before `func` is invoked.
      * @param {Function} func The function to restrict.
      * @returns {Function} Returns the new restricted function.
      * @example
@@ -5127,18 +7282,25 @@
      * var saves = ['profile', 'settings'];
      *
      * var done = _.after(saves.length, function() {
-     *   console.log('Done saving!');
+     *   console.log('done saving!');
      * });
      *
      * _.forEach(saves, function(type) {
      *   asyncSave({ 'type': type, 'complete': done });
      * });
-     * // => logs 'Done saving!', after all saves have completed
+     * // => logs 'done saving!' after the two async saves have completed
      */
     function after(n, func) {
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
+      if (typeof func != 'function') {
+        if (typeof n == 'function') {
+          var temp = n;
+          n = func;
+          func = temp;
+        } else {
+          throw new TypeError(FUNC_ERROR_TEXT);
+        }
+      }
+      n = nativeIsFinite(n = +n) ? n : 0;
       return function() {
         if (--n < 1) {
           return func.apply(this, arguments);
@@ -5147,230 +7309,348 @@
     }
 
     /**
-     * Creates a function that, when called, invokes `func` with the `this`
-     * binding of `thisArg` and prepends any additional `bind` arguments to those
-     * provided to the bound function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * Creates a function that accepts up to `n` arguments ignoring any
+     * additional arguments.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to cap arguments for.
+     * @param {number} [n=func.length] The arity cap.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * _.map(['6', '8', '10'], _.ary(parseInt, 1));
+     * // => [6, 8, 10]
+     */
+    function ary(func, n, guard) {
+      if (guard && isIterateeCall(func, n, guard)) {
+        n = undefined;
+      }
+      n = (func && n == null) ? func.length : nativeMax(+n || 0, 0);
+      return createWrapper(func, ARY_FLAG, undefined, undefined, undefined, undefined, n);
+    }
+
+    /**
+     * Creates a function that invokes `func`, with the `this` binding and arguments
+     * of the created function, while it's called less than `n` times. Subsequent
+     * calls to the created function return the result of the last `func` invocation.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {number} n The number of calls at which `func` is no longer invoked.
+     * @param {Function} func The function to restrict.
+     * @returns {Function} Returns the new restricted function.
+     * @example
+     *
+     * jQuery('#add').on('click', _.before(5, addContactToList));
+     * // => allows adding up to 4 contacts to the list
+     */
+    function before(n, func) {
+      var result;
+      if (typeof func != 'function') {
+        if (typeof n == 'function') {
+          var temp = n;
+          n = func;
+          func = temp;
+        } else {
+          throw new TypeError(FUNC_ERROR_TEXT);
+        }
+      }
+      return function() {
+        if (--n > 0) {
+          result = func.apply(this, arguments);
+        }
+        if (n <= 1) {
+          func = undefined;
+        }
+        return result;
+      };
+    }
+
+    /**
+     * Creates a function that invokes `func` with the `this` binding of `thisArg`
+     * and prepends any additional `_.bind` arguments to those provided to the
+     * bound function.
+     *
+     * The `_.bind.placeholder` value, which defaults to `_` in monolithic builds,
+     * may be used as a placeholder for partially applied arguments.
+     *
+     * **Note:** Unlike native `Function#bind` this method does not set the "length"
+     * property of bound functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to bind.
-     * @param {*} [thisArg] The `this` binding of `func`.
-     * @param {...*} [arg] Arguments to be partially applied.
+     * @param {*} thisArg The `this` binding of `func`.
+     * @param {...*} [partials] The arguments to be partially applied.
      * @returns {Function} Returns the new bound function.
      * @example
      *
-     * var func = function(greeting) {
-     *   return greeting + ' ' + this.name;
+     * var greet = function(greeting, punctuation) {
+     *   return greeting + ' ' + this.user + punctuation;
      * };
      *
-     * func = _.bind(func, { 'name': 'fred' }, 'hi');
-     * func();
-     * // => 'hi fred'
-     */
-    function bind(func, thisArg) {
-      return arguments.length > 2
-        ? createWrapper(func, 17, slice(arguments, 2), null, thisArg)
-        : createWrapper(func, 1, null, null, thisArg);
-    }
+     * var object = { 'user': 'fred' };
+     *
+     * var bound = _.bind(greet, object, 'hi');
+     * bound('!');
+     * // => 'hi fred!'
+     *
+     * // using placeholders
+     * var bound = _.bind(greet, object, _, '!');
+     * bound('hi');
+     * // => 'hi fred!'
+     */
+    var bind = restParam(function(func, thisArg, partials) {
+      var bitmask = BIND_FLAG;
+      if (partials.length) {
+        var holders = replaceHolders(partials, bind.placeholder);
+        bitmask |= PARTIAL_FLAG;
+      }
+      return createWrapper(func, bitmask, thisArg, partials, holders);
+    });
 
     /**
      * Binds methods of an object to the object itself, overwriting the existing
      * method. Method names may be specified as individual arguments or as arrays
-     * of method names. If no method names are provided all the function properties
-     * of `object` will be bound.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * of method names. If no method names are provided all enumerable function
+     * properties, own and inherited, of `object` are bound.
+     *
+     * **Note:** This method does not set the "length" property of bound functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Object} object The object to bind and assign the bound methods to.
-     * @param {...string} [methodName] The object method names to
-     *  bind, specified as individual method names or arrays of method names.
+     * @param {...(string|string[])} [methodNames] The object method names to bind,
+     *  specified as individual method names or arrays of method names.
      * @returns {Object} Returns `object`.
      * @example
      *
      * var view = {
      *   'label': 'docs',
-     *   'onClick': function() { console.log('clicked ' + this.label); }
+     *   'onClick': function() {
+     *     console.log('clicked ' + this.label);
+     *   }
      * };
      *
      * _.bindAll(view);
      * jQuery('#docs').on('click', view.onClick);
-     * // => logs 'clicked docs', when the button is clicked
-     */
-    function bindAll(object) {
-      var funcs = arguments.length > 1 ? baseFlatten(arguments, true, false, 1) : functions(object),
-          index = -1,
-          length = funcs.length;
+     * // => logs 'clicked docs' when the element is clicked
+     */
+    var bindAll = restParam(function(object, methodNames) {
+      methodNames = methodNames.length ? baseFlatten(methodNames) : functions(object);
+
+      var index = -1,
+          length = methodNames.length;
 
       while (++index < length) {
-        var key = funcs[index];
-        object[key] = createWrapper(object[key], 1, null, null, object);
+        var key = methodNames[index];
+        object[key] = createWrapper(object[key], BIND_FLAG, object);
       }
       return object;
-    }
-
-    /**
-     * Creates a function that, when called, invokes the method at `object[key]`
-     * and prepends any additional `bindKey` arguments to those provided to the bound
-     * function. This method differs from `_.bind` by allowing bound functions to
-     * reference methods that will be redefined or don't yet exist.
-     * See http://michaux.ca/articles/lazy-function-definition-pattern.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+    });
+
+    /**
+     * Creates a function that invokes the method at `object[key]` and prepends
+     * any additional `_.bindKey` arguments to those provided to the bound function.
+     *
+     * This method differs from `_.bind` by allowing bound functions to reference
+     * methods that may be redefined or don't yet exist.
+     * See [Peter Michaux's article](http://peter.michaux.ca/articles/lazy-function-definition-pattern)
+     * for more details.
+     *
+     * The `_.bindKey.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for partially applied arguments.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Object} object The object the method belongs to.
      * @param {string} key The key of the method.
-     * @param {...*} [arg] Arguments to be partially applied.
+     * @param {...*} [partials] The arguments to be partially applied.
      * @returns {Function} Returns the new bound function.
      * @example
      *
      * var object = {
-     *   'name': 'fred',
-     *   'greet': function(greeting) {
-     *     return greeting + ' ' + this.name;
+     *   'user': 'fred',
+     *   'greet': function(greeting, punctuation) {
+     *     return greeting + ' ' + this.user + punctuation;
      *   }
      * };
      *
-     * var func = _.bindKey(object, 'greet', 'hi');
-     * func();
-     * // => 'hi fred'
-     *
-     * object.greet = function(greeting) {
-     *   return greeting + 'ya ' + this.name + '!';
-     * };
-     *
-     * func();
-     * // => 'hiya fred!'
-     */
-    function bindKey(object, key) {
-      return arguments.length > 2
-        ? createWrapper(key, 19, slice(arguments, 2), null, object)
-        : createWrapper(key, 3, null, null, object);
-    }
-
-    /**
-     * Creates a function that is the composition of the provided functions,
-     * where each function consumes the return value of the function that follows.
-     * For example, composing the functions `f()`, `g()`, and `h()` produces `f(g(h()))`.
-     * Each function is executed with the `this` binding of the composed function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
-     * @param {...Function} [func] Functions to compose.
-     * @returns {Function} Returns the new composed function.
-     * @example
-     *
-     * var realNameMap = {
-     *   'pebbles': 'penelope'
-     * };
-     *
-     * var format = function(name) {
-     *   name = realNameMap[name.toLowerCase()] || name;
-     *   return name.charAt(0).toUpperCase() + name.slice(1).toLowerCase();
+     * var bound = _.bindKey(object, 'greet', 'hi');
+     * bound('!');
+     * // => 'hi fred!'
+     *
+     * object.greet = function(greeting, punctuation) {
+     *   return greeting + 'ya ' + this.user + punctuation;
      * };
      *
-     * var greet = function(formatted) {
-     *   return 'Hiya ' + formatted + '!';
-     * };
-     *
-     * var welcome = _.compose(greet, format);
-     * welcome('pebbles');
-     * // => 'Hiya Penelope!'
-     */
-    function compose() {
-      var funcs = arguments,
-          length = funcs.length;
-
-      while (length--) {
-        if (!isFunction(funcs[length])) {
-          throw new TypeError;
-        }
-      }
-      return function() {
-        var args = arguments,
-            length = funcs.length;
-
-        while (length--) {
-          args = [funcs[length].apply(this, args)];
-        }
-        return args[0];
-      };
-    }
-
-    /**
-     * Creates a function which accepts one or more arguments of `func` that when
-     * invoked either executes `func` returning its result, if all `func` arguments
+     * bound('!');
+     * // => 'hiya fred!'
+     *
+     * // using placeholders
+     * var bound = _.bindKey(object, 'greet', _, '!');
+     * bound('hi');
+     * // => 'hiya fred!'
+     */
+    var bindKey = restParam(function(object, key, partials) {
+      var bitmask = BIND_FLAG | BIND_KEY_FLAG;
+      if (partials.length) {
+        var holders = replaceHolders(partials, bindKey.placeholder);
+        bitmask |= PARTIAL_FLAG;
+      }
+      return createWrapper(key, bitmask, object, partials, holders);
+    });
+
+    /**
+     * Creates a function that accepts one or more arguments of `func` that when
+     * called either invokes `func` returning its result, if all `func` arguments
      * have been provided, or returns a function that accepts one or more of the
-     * remaining `func` arguments, and so on. The arity of `func` can be specified
+     * remaining `func` arguments, and so on. The arity of `func` may be specified
      * if `func.length` is not sufficient.
      *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * The `_.curry.placeholder` value, which defaults to `_` in monolithic builds,
+     * may be used as a placeholder for provided arguments.
+     *
+     * **Note:** This method does not set the "length" property of curried functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to curry.
      * @param {number} [arity=func.length] The arity of `func`.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
      * @returns {Function} Returns the new curried function.
      * @example
      *
-     * var curried = _.curry(function(a, b, c) {
-     *   console.log(a + b + c);
-     * });
+     * var abc = function(a, b, c) {
+     *   return [a, b, c];
+     * };
+     *
+     * var curried = _.curry(abc);
      *
      * curried(1)(2)(3);
-     * // => 6
+     * // => [1, 2, 3]
      *
      * curried(1, 2)(3);
-     * // => 6
+     * // => [1, 2, 3]
      *
      * curried(1, 2, 3);
-     * // => 6
-     */
-    function curry(func, arity) {
-      arity = typeof arity == 'number' ? arity : (+arity || func.length);
-      return createWrapper(func, 4, null, null, null, arity);
-    }
-
-    /**
-     * Creates a function that will delay the execution of `func` until after
-     * `wait` milliseconds have elapsed since the last time it was invoked.
-     * Provide an options object to indicate that `func` should be invoked on
-     * the leading and/or trailing edge of the `wait` timeout. Subsequent calls
-     * to the debounced function will return the result of the last `func` call.
-     *
-     * Note: If `leading` and `trailing` options are `true` `func` will be called
+     * // => [1, 2, 3]
+     *
+     * // using placeholders
+     * curried(1)(_, 3)(2);
+     * // => [1, 2, 3]
+     */
+    var curry = createCurry(CURRY_FLAG);
+
+    /**
+     * This method is like `_.curry` except that arguments are applied to `func`
+     * in the manner of `_.partialRight` instead of `_.partial`.
+     *
+     * The `_.curryRight.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for provided arguments.
+     *
+     * **Note:** This method does not set the "length" property of curried functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to curry.
+     * @param {number} [arity=func.length] The arity of `func`.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Function} Returns the new curried function.
+     * @example
+     *
+     * var abc = function(a, b, c) {
+     *   return [a, b, c];
+     * };
+     *
+     * var curried = _.curryRight(abc);
+     *
+     * curried(3)(2)(1);
+     * // => [1, 2, 3]
+     *
+     * curried(2, 3)(1);
+     * // => [1, 2, 3]
+     *
+     * curried(1, 2, 3);
+     * // => [1, 2, 3]
+     *
+     * // using placeholders
+     * curried(3)(1, _)(2);
+     * // => [1, 2, 3]
+     */
+    var curryRight = createCurry(CURRY_RIGHT_FLAG);
+
+    /**
+     * Creates a debounced function that delays invoking `func` until after `wait`
+     * milliseconds have elapsed since the last time the debounced function was
+     * invoked. The debounced function comes with a `cancel` method to cancel
+     * delayed invocations. Provide an options object to indicate that `func`
+     * should be invoked on the leading and/or trailing edge of the `wait` timeout.
+     * Subsequent calls to the debounced function return the result of the last
+     * `func` invocation.
+     *
+     * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
      * on the trailing edge of the timeout only if the the debounced function is
      * invoked more than once during the `wait` timeout.
      *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
+     * for details over the differences between `_.debounce` and `_.throttle`.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to debounce.
-     * @param {number} wait The number of milliseconds to delay.
+     * @param {number} [wait=0] The number of milliseconds to delay.
      * @param {Object} [options] The options object.
-     * @param {boolean} [options.leading=false] Specify execution on the leading edge of the timeout.
-     * @param {number} [options.maxWait] The maximum time `func` is allowed to be delayed before it's called.
-     * @param {boolean} [options.trailing=true] Specify execution on the trailing edge of the timeout.
+     * @param {boolean} [options.leading=false] Specify invoking on the leading
+     *  edge of the timeout.
+     * @param {number} [options.maxWait] The maximum time `func` is allowed to be
+     *  delayed before it's invoked.
+     * @param {boolean} [options.trailing=true] Specify invoking on the trailing
+     *  edge of the timeout.
      * @returns {Function} Returns the new debounced function.
      * @example
      *
      * // avoid costly calculations while the window size is in flux
-     * var lazyLayout = _.debounce(calculateLayout, 150);
-     * jQuery(window).on('resize', lazyLayout);
-     *
-     * // execute `sendMail` when the click event is fired, debouncing subsequent calls
+     * jQuery(window).on('resize', _.debounce(calculateLayout, 150));
+     *
+     * // invoke `sendMail` when the click event is fired, debouncing subsequent calls
      * jQuery('#postbox').on('click', _.debounce(sendMail, 300, {
      *   'leading': true,
      *   'trailing': false
-     * });
-     *
-     * // ensure `batchLog` is executed once after 1 second of debounced calls
+     * }));
+     *
+     * // ensure `batchLog` is invoked once after 1 second of debounced calls
      * var source = new EventSource('/stream');
-     * source.addEventListener('message', _.debounce(batchLog, 250, {
+     * jQuery(source).on('message', _.debounce(batchLog, 250, {
      *   'maxWait': 1000
-     * }, false);
+     * }));
+     *
+     * // cancel a debounced call
+     * var todoChanges = _.debounce(batchLog, 1000);
+     * Object.observe(models.todo, todoChanges);
+     *
+     * Object.observe(models, function(changes) {
+     *   if (_.find(changes, { 'user': 'todo', 'type': 'delete'})) {
+     *     todoChanges.cancel();
+     *   }
+     * }, ['delete']);
+     *
+     * // ...at some point `models.todo` is changed
+     * models.todo.completed = true;
+     *
+     * // ...before 1 second has passed `models.todo` is deleted
+     * // which cancels the debounced `todoChanges` call
+     * delete models.todo;
      */
     function debounce(func, wait, options) {
       var args,
@@ -5384,53 +7664,58 @@
           maxWait = false,
           trailing = true;
 
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      wait = nativeMax(0, wait) || 0;
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      wait = wait < 0 ? 0 : (+wait || 0);
       if (options === true) {
         var leading = true;
         trailing = false;
       } else if (isObject(options)) {
-        leading = options.leading;
-        maxWait = 'maxWait' in options && (nativeMax(wait, options.maxWait) || 0);
-        trailing = 'trailing' in options ? options.trailing : trailing;
-      }
-      var delayed = function() {
-        var remaining = wait - (now() - stamp);
-        if (remaining <= 0) {
-          if (maxTimeoutId) {
-            clearTimeout(maxTimeoutId);
-          }
-          var isCalled = trailingCall;
-          maxTimeoutId = timeoutId = trailingCall = undefined;
-          if (isCalled) {
-            lastCalled = now();
-            result = func.apply(thisArg, args);
-            if (!timeoutId && !maxTimeoutId) {
-              args = thisArg = null;
-            }
-          }
-        } else {
-          timeoutId = setTimeout(delayed, remaining);
-        }
-      };
-
-      var maxDelayed = function() {
+        leading = !!options.leading;
+        maxWait = 'maxWait' in options && nativeMax(+options.maxWait || 0, wait);
+        trailing = 'trailing' in options ? !!options.trailing : trailing;
+      }
+
+      function cancel() {
         if (timeoutId) {
           clearTimeout(timeoutId);
         }
+        if (maxTimeoutId) {
+          clearTimeout(maxTimeoutId);
+        }
+        lastCalled = 0;
         maxTimeoutId = timeoutId = trailingCall = undefined;
-        if (trailing || (maxWait !== wait)) {
+      }
+
+      function complete(isCalled, id) {
+        if (id) {
+          clearTimeout(id);
+        }
+        maxTimeoutId = timeoutId = trailingCall = undefined;
+        if (isCalled) {
           lastCalled = now();
           result = func.apply(thisArg, args);
           if (!timeoutId && !maxTimeoutId) {
-            args = thisArg = null;
+            args = thisArg = undefined;
           }
         }
-      };
-
-      return function() {
+      }
+
+      function delayed() {
+        var remaining = wait - (now() - stamp);
+        if (remaining <= 0 || remaining > wait) {
+          complete(trailingCall, maxTimeoutId);
+        } else {
+          timeoutId = setTimeout(delayed, remaining);
+        }
+      }
+
+      function maxDelayed() {
+        complete(trailing, timeoutId);
+      }
+
+      function debounced() {
         args = arguments;
         stamp = now();
         thisArg = this;
@@ -5443,7 +7728,7 @@
             lastCalled = stamp;
           }
           var remaining = maxWait - (stamp - lastCalled),
-              isCalled = remaining <= 0;
+              isCalled = remaining <= 0 || remaining > maxWait;
 
           if (isCalled) {
             if (maxTimeoutId) {
@@ -5467,120 +7752,254 @@
           result = func.apply(thisArg, args);
         }
         if (isCalled && !timeoutId && !maxTimeoutId) {
-          args = thisArg = null;
+          args = thisArg = undefined;
         }
         return result;
-      };
-    }
-
-    /**
-     * Defers executing the `func` function until the current call stack has cleared.
-     * Additional arguments will be provided to `func` when it is invoked.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+      }
+      debounced.cancel = cancel;
+      return debounced;
+    }
+
+    /**
+     * Defers invoking the `func` until the current call stack has cleared. Any
+     * additional arguments are provided to `func` when it's invoked.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to defer.
-     * @param {...*} [arg] Arguments to invoke the function with.
+     * @param {...*} [args] The arguments to invoke the function with.
      * @returns {number} Returns the timer id.
      * @example
      *
-     * _.defer(function(text) { console.log(text); }, 'deferred');
+     * _.defer(function(text) {
+     *   console.log(text);
+     * }, 'deferred');
      * // logs 'deferred' after one or more milliseconds
      */
-    function defer(func) {
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      var args = slice(arguments, 1);
-      return setTimeout(function() { func.apply(undefined, args); }, 1);
-    }
-
-    /**
-     * Executes the `func` function after `wait` milliseconds. Additional arguments
-     * will be provided to `func` when it is invoked.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+    var defer = restParam(function(func, args) {
+      return baseDelay(func, 1, args);
+    });
+
+    /**
+     * Invokes `func` after `wait` milliseconds. Any additional arguments are
+     * provided to `func` when it's invoked.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to delay.
-     * @param {number} wait The number of milliseconds to delay execution.
-     * @param {...*} [arg] Arguments to invoke the function with.
+     * @param {number} wait The number of milliseconds to delay invocation.
+     * @param {...*} [args] The arguments to invoke the function with.
      * @returns {number} Returns the timer id.
      * @example
      *
-     * _.delay(function(text) { console.log(text); }, 1000, 'later');
+     * _.delay(function(text) {
+     *   console.log(text);
+     * }, 1000, 'later');
      * // => logs 'later' after one second
      */
-    function delay(func, wait) {
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      var args = slice(arguments, 2);
-      return setTimeout(function() { func.apply(undefined, args); }, wait);
-    }
+    var delay = restParam(function(func, wait, args) {
+      return baseDelay(func, wait, args);
+    });
+
+    /**
+     * Creates a function that returns the result of invoking the provided
+     * functions with the `this` binding of the created function, where each
+     * successive invocation is supplied the return value of the previous.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {...Function} [funcs] Functions to invoke.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * function square(n) {
+     *   return n * n;
+     * }
+     *
+     * var addSquare = _.flow(_.add, square);
+     * addSquare(1, 2);
+     * // => 9
+     */
+    var flow = createFlow();
+
+    /**
+     * This method is like `_.flow` except that it creates a function that
+     * invokes the provided functions from right to left.
+     *
+     * @static
+     * @memberOf _
+     * @alias backflow, compose
+     * @category Function
+     * @param {...Function} [funcs] Functions to invoke.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * function square(n) {
+     *   return n * n;
+     * }
+     *
+     * var addSquare = _.flowRight(square, _.add);
+     * addSquare(1, 2);
+     * // => 9
+     */
+    var flowRight = createFlow(true);
 
     /**
      * Creates a function that memoizes the result of `func`. If `resolver` is
-     * provided it will be used to determine the cache key for storing the result
-     * based on the arguments provided to the memoized function. By default, the
-     * first argument provided to the memoized function is used as the cache key.
-     * The `func` is executed with the `this` binding of the memoized function.
-     * The result cache is exposed as the `cache` property on the memoized function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * provided it determines the cache key for storing the result based on the
+     * arguments provided to the memoized function. By default, the first argument
+     * provided to the memoized function is coerced to a string and used as the
+     * cache key. The `func` is invoked with the `this` binding of the memoized
+     * function.
+     *
+     * **Note:** The cache is exposed as the `cache` property on the memoized
+     * function. Its creation may be customized by replacing the `_.memoize.Cache`
+     * constructor with one whose instances implement the [`Map`](http://ecma-international.org/ecma-262/6.0/#sec-properties-of-the-map-prototype-object)
+     * method interface of `get`, `has`, and `set`.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to have its output memoized.
-     * @param {Function} [resolver] A function used to resolve the cache key.
+     * @param {Function} [resolver] The function to resolve the cache key.
      * @returns {Function} Returns the new memoizing function.
      * @example
      *
-     * var fibonacci = _.memoize(function(n) {
-     *   return n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2);
+     * var upperCase = _.memoize(function(string) {
+     *   return string.toUpperCase();
      * });
      *
-     * fibonacci(9)
-     * // => 34
-     *
-     * var data = {
-     *   'fred': { 'name': 'fred', 'age': 40 },
-     *   'pebbles': { 'name': 'pebbles', 'age': 1 }
-     * };
+     * upperCase('fred');
+     * // => 'FRED'
      *
      * // modifying the result cache
-     * var get = _.memoize(function(name) { return data[name]; }, _.identity);
-     * get('pebbles');
-     * // => { 'name': 'pebbles', 'age': 1 }
-     *
-     * get.cache.pebbles.name = 'penelope';
-     * get('pebbles');
-     * // => { 'name': 'penelope', 'age': 1 }
+     * upperCase.cache.set('fred', 'BARNEY');
+     * upperCase('fred');
+     * // => 'BARNEY'
+     *
+     * // replacing `_.memoize.Cache`
+     * var object = { 'user': 'fred' };
+     * var other = { 'user': 'barney' };
+     * var identity = _.memoize(_.identity);
+     *
+     * identity(object);
+     * // => { 'user': 'fred' }
+     * identity(other);
+     * // => { 'user': 'fred' }
+     *
+     * _.memoize.Cache = WeakMap;
+     * var identity = _.memoize(_.identity);
+     *
+     * identity(object);
+     * // => { 'user': 'fred' }
+     * identity(other);
+     * // => { 'user': 'barney' }
      */
     function memoize(func, resolver) {
-      if (!isFunction(func)) {
-        throw new TypeError;
+      if (typeof func != 'function' || (resolver && typeof resolver != 'function')) {
+        throw new TypeError(FUNC_ERROR_TEXT);
       }
       var memoized = function() {
-        var cache = memoized.cache,
-            key = resolver ? resolver.apply(this, arguments) : keyPrefix + arguments[0];
-
-        return hasOwnProperty.call(cache, key)
-          ? cache[key]
-          : (cache[key] = func.apply(this, arguments));
-      }
-      memoized.cache = {};
+        var args = arguments,
+            key = resolver ? resolver.apply(this, args) : args[0],
+            cache = memoized.cache;
+
+        if (cache.has(key)) {
+          return cache.get(key);
+        }
+        var result = func.apply(this, args);
+        memoized.cache = cache.set(key, result);
+        return result;
+      };
+      memoized.cache = new memoize.Cache;
       return memoized;
     }
 
     /**
-     * Creates a function that is restricted to execute `func` once. Repeat calls to
-     * the function will return the value of the first call. The `func` is executed
-     * with the `this` binding of the created function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * Creates a function that runs each argument through a corresponding
+     * transform function.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to wrap.
+     * @param {...(Function|Function[])} [transforms] The functions to transform
+     * arguments, specified as individual functions or arrays of functions.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * function doubled(n) {
+     *   return n * 2;
+     * }
+     *
+     * function square(n) {
+     *   return n * n;
+     * }
+     *
+     * var modded = _.modArgs(function(x, y) {
+     *   return [x, y];
+     * }, square, doubled);
+     *
+     * modded(1, 2);
+     * // => [1, 4]
+     *
+     * modded(5, 10);
+     * // => [25, 20]
+     */
+    var modArgs = restParam(function(func, transforms) {
+      transforms = baseFlatten(transforms);
+      if (typeof func != 'function' || !arrayEvery(transforms, baseIsFunction)) {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      var length = transforms.length;
+      return restParam(function(args) {
+        var index = nativeMin(args.length, length);
+        while (index--) {
+          args[index] = transforms[index](args[index]);
+        }
+        return func.apply(this, args);
+      });
+    });
+
+    /**
+     * Creates a function that negates the result of the predicate `func`. The
+     * `func` predicate is invoked with the `this` binding and arguments of the
+     * created function.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} predicate The predicate to negate.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * function isEven(n) {
+     *   return n % 2 == 0;
+     * }
+     *
+     * _.filter([1, 2, 3, 4, 5, 6], _.negate(isEven));
+     * // => [1, 3, 5]
+     */
+    function negate(predicate) {
+      if (typeof predicate != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      return function() {
+        return !predicate.apply(this, arguments);
+      };
+    }
+
+    /**
+     * Creates a function that is restricted to invoking `func` once. Repeat calls
+     * to the function return the value of the first call. The `func` is invoked
+     * with the `this` binding and arguments of the created function.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to restrict.
      * @returns {Function} Returns the new restricted function.
      * @example
@@ -5588,141 +8007,266 @@
      * var initialize = _.once(createApplication);
      * initialize();
      * initialize();
-     * // `initialize` executes `createApplication` once
+     * // `initialize` invokes `createApplication` once
      */
     function once(func) {
-      var ran,
-          result;
-
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      return function() {
-        if (ran) {
-          return result;
-        }
-        ran = true;
-        result = func.apply(this, arguments);
-
-        // clear the `func` variable so the function may be garbage collected
-        func = null;
-        return result;
-      };
-    }
-
-    /**
-     * Creates a function that, when called, invokes `func` with any additional
-     * `partial` arguments prepended to those provided to the new function. This
-     * method is similar to `_.bind` except it does **not** alter the `this` binding.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+      return before(2, func);
+    }
+
+    /**
+     * Creates a function that invokes `func` with `partial` arguments prepended
+     * to those provided to the new function. This method is like `_.bind` except
+     * it does **not** alter the `this` binding.
+     *
+     * The `_.partial.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for partially applied arguments.
+     *
+     * **Note:** This method does not set the "length" property of partially
+     * applied functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to partially apply arguments to.
-     * @param {...*} [arg] Arguments to be partially applied.
+     * @param {...*} [partials] The arguments to be partially applied.
      * @returns {Function} Returns the new partially applied function.
      * @example
      *
-     * var greet = function(greeting, name) { return greeting + ' ' + name; };
-     * var hi = _.partial(greet, 'hi');
-     * hi('fred');
+     * var greet = function(greeting, name) {
+     *   return greeting + ' ' + name;
+     * };
+     *
+     * var sayHelloTo = _.partial(greet, 'hello');
+     * sayHelloTo('fred');
+     * // => 'hello fred'
+     *
+     * // using placeholders
+     * var greetFred = _.partial(greet, _, 'fred');
+     * greetFred('hi');
+     * // => 'hi fred'
+     */
+    var partial = createPartial(PARTIAL_FLAG);
+
+    /**
+     * This method is like `_.partial` except that partially applied arguments
+     * are appended to those provided to the new function.
+     *
+     * The `_.partialRight.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for partially applied arguments.
+     *
+     * **Note:** This method does not set the "length" property of partially
+     * applied functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to partially apply arguments to.
+     * @param {...*} [partials] The arguments to be partially applied.
+     * @returns {Function} Returns the new partially applied function.
+     * @example
+     *
+     * var greet = function(greeting, name) {
+     *   return greeting + ' ' + name;
+     * };
+     *
+     * var greetFred = _.partialRight(greet, 'fred');
+     * greetFred('hi');
      * // => 'hi fred'
-     */
-    function partial(func) {
-      return createWrapper(func, 16, slice(arguments, 1));
-    }
-
-    /**
-     * This method is like `_.partial` except that `partial` arguments are
-     * appended to those provided to the new function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to partially apply arguments to.
-     * @param {...*} [arg] Arguments to be partially applied.
-     * @returns {Function} Returns the new partially applied function.
-     * @example
-     *
-     * var defaultsDeep = _.partialRight(_.merge, _.defaults);
-     *
-     * var options = {
-     *   'variable': 'data',
-     *   'imports': { 'jq': $ }
-     * };
-     *
-     * defaultsDeep(options, _.templateSettings);
-     *
-     * options.variable
-     * // => 'data'
-     *
-     * options.imports
-     * // => { '_': _, 'jq': $ }
-     */
-    function partialRight(func) {
-      return createWrapper(func, 32, null, slice(arguments, 1));
-    }
-
-    /**
-     * Creates a function that, when executed, will only call the `func` function
-     * at most once per every `wait` milliseconds. Provide an options object to
-     * indicate that `func` should be invoked on the leading and/or trailing edge
-     * of the `wait` timeout. Subsequent calls to the throttled function will
-     * return the result of the last `func` call.
-     *
-     * Note: If `leading` and `trailing` options are `true` `func` will be called
+     *
+     * // using placeholders
+     * var sayHelloTo = _.partialRight(greet, 'hello', _);
+     * sayHelloTo('fred');
+     * // => 'hello fred'
+     */
+    var partialRight = createPartial(PARTIAL_RIGHT_FLAG);
+
+    /**
+     * Creates a function that invokes `func` with arguments arranged according
+     * to the specified indexes where the argument value at the first index is
+     * provided as the first argument, the argument value at the second index is
+     * provided as the second argument, and so on.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to rearrange arguments for.
+     * @param {...(number|number[])} indexes The arranged argument indexes,
+     *  specified as individual indexes or arrays of indexes.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var rearged = _.rearg(function(a, b, c) {
+     *   return [a, b, c];
+     * }, 2, 0, 1);
+     *
+     * rearged('b', 'c', 'a')
+     * // => ['a', 'b', 'c']
+     *
+     * var map = _.rearg(_.map, [1, 0]);
+     * map(function(n) {
+     *   return n * 3;
+     * }, [1, 2, 3]);
+     * // => [3, 6, 9]
+     */
+    var rearg = restParam(function(func, indexes) {
+      return createWrapper(func, REARG_FLAG, undefined, undefined, undefined, baseFlatten(indexes));
+    });
+
+    /**
+     * Creates a function that invokes `func` with the `this` binding of the
+     * created function and arguments from `start` and beyond provided as an array.
+     *
+     * **Note:** This method is based on the [rest parameter](https://developer.mozilla.org/Web/JavaScript/Reference/Functions/rest_parameters).
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to apply a rest parameter to.
+     * @param {number} [start=func.length-1] The start position of the rest parameter.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var say = _.restParam(function(what, names) {
+     *   return what + ' ' + _.initial(names).join(', ') +
+     *     (_.size(names) > 1 ? ', & ' : '') + _.last(names);
+     * });
+     *
+     * say('hello', 'fred', 'barney', 'pebbles');
+     * // => 'hello fred, barney, & pebbles'
+     */
+    function restParam(func, start) {
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      start = nativeMax(start === undefined ? (func.length - 1) : (+start || 0), 0);
+      return function() {
+        var args = arguments,
+            index = -1,
+            length = nativeMax(args.length - start, 0),
+            rest = Array(length);
+
+        while (++index < length) {
+          rest[index] = args[start + index];
+        }
+        switch (start) {
+          case 0: return func.call(this, rest);
+          case 1: return func.call(this, args[0], rest);
+          case 2: return func.call(this, args[0], args[1], rest);
+        }
+        var otherArgs = Array(start + 1);
+        index = -1;
+        while (++index < start) {
+          otherArgs[index] = args[index];
+        }
+        otherArgs[start] = rest;
+        return func.apply(this, otherArgs);
+      };
+    }
+
+    /**
+     * Creates a function that invokes `func` with the `this` binding of the created
+     * function and an array of arguments much like [`Function#apply`](https://es5.github.io/#x15.3.4.3).
+     *
+     * **Note:** This method is based on the [spread operator](https://developer.mozilla.org/Web/JavaScript/Reference/Operators/Spread_operator).
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to spread arguments over.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var say = _.spread(function(who, what) {
+     *   return who + ' says ' + what;
+     * });
+     *
+     * say(['fred', 'hello']);
+     * // => 'fred says hello'
+     *
+     * // with a Promise
+     * var numbers = Promise.all([
+     *   Promise.resolve(40),
+     *   Promise.resolve(36)
+     * ]);
+     *
+     * numbers.then(_.spread(function(x, y) {
+     *   return x + y;
+     * }));
+     * // => a Promise of 76
+     */
+    function spread(func) {
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      return function(array) {
+        return func.apply(this, array);
+      };
+    }
+
+    /**
+     * Creates a throttled function that only invokes `func` at most once per
+     * every `wait` milliseconds. The throttled function comes with a `cancel`
+     * method to cancel delayed invocations. Provide an options object to indicate
+     * that `func` should be invoked on the leading and/or trailing edge of the
+     * `wait` timeout. Subsequent calls to the throttled function return the
+     * result of the last `func` call.
+     *
+     * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
      * on the trailing edge of the timeout only if the the throttled function is
      * invoked more than once during the `wait` timeout.
      *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
+     * for details over the differences between `_.throttle` and `_.debounce`.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to throttle.
-     * @param {number} wait The number of milliseconds to throttle executions to.
+     * @param {number} [wait=0] The number of milliseconds to throttle invocations to.
      * @param {Object} [options] The options object.
-     * @param {boolean} [options.leading=true] Specify execution on the leading edge of the timeout.
-     * @param {boolean} [options.trailing=true] Specify execution on the trailing edge of the timeout.
+     * @param {boolean} [options.leading=true] Specify invoking on the leading
+     *  edge of the timeout.
+     * @param {boolean} [options.trailing=true] Specify invoking on the trailing
+     *  edge of the timeout.
      * @returns {Function} Returns the new throttled function.
      * @example
      *
      * // avoid excessively updating the position while scrolling
-     * var throttled = _.throttle(updatePosition, 100);
-     * jQuery(window).on('scroll', throttled);
-     *
-     * // execute `renewToken` when the click event is fired, but not more than once every 5 minutes
+     * jQuery(window).on('scroll', _.throttle(updatePosition, 100));
+     *
+     * // invoke `renewToken` when the click event is fired, but not more than once every 5 minutes
      * jQuery('.interactive').on('click', _.throttle(renewToken, 300000, {
      *   'trailing': false
      * }));
+     *
+     * // cancel a trailing throttled call
+     * jQuery(window).on('popstate', throttled.cancel);
      */
     function throttle(func, wait, options) {
       var leading = true,
           trailing = true;
 
-      if (!isFunction(func)) {
-        throw new TypeError;
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
       }
       if (options === false) {
         leading = false;
       } else if (isObject(options)) {
-        leading = 'leading' in options ? options.leading : leading;
-        trailing = 'trailing' in options ? options.trailing : trailing;
-      }
-      debounceOptions.leading = leading;
-      debounceOptions.maxWait = wait;
-      debounceOptions.trailing = trailing;
-
-      return debounce(func, wait, debounceOptions);
+        leading = 'leading' in options ? !!options.leading : leading;
+        trailing = 'trailing' in options ? !!options.trailing : trailing;
+      }
+      return debounce(func, wait, { 'leading': leading, 'maxWait': +wait, 'trailing': trailing });
     }
 
     /**
      * Creates a function that provides `value` to the wrapper function as its
-     * first argument. Additional arguments provided to the function are appended
-     * to those provided to the wrapper function. The wrapper is executed with
-     * the `this` binding of the created function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * first argument. Any additional arguments provided to the function are
+     * appended to those provided to the wrapper function. The wrapper is invoked
+     * with the `this` binding of the created function.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {*} value The value to wrap.
      * @param {Function} wrapper The wrapper function.
      * @returns {Function} Returns the new function.
@@ -5732,327 +8276,1879 @@
      *   return '<p>' + func(text) + '</p>';
      * });
      *
-     * p('Fred, Wilma, & Pebbles');
-     * // => '<p>Fred, Wilma, &amp; Pebbles</p>'
+     * p('fred, barney, & pebbles');
+     * // => '<p>fred, barney, &amp; pebbles</p>'
      */
     function wrap(value, wrapper) {
-      return createWrapper(wrapper, 16, [value]);
-    }
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates a function that returns `value`.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {*} value The value to return from the new function.
-     * @returns {Function} Returns the new function.
-     * @example
-     *
-     * var object = { 'name': 'fred' };
-     * var getter = _.constant(object);
-     * getter() === object;
+      wrapper = wrapper == null ? identity : wrapper;
+      return createWrapper(wrapper, PARTIAL_FLAG, undefined, [value], []);
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a clone of `value`. If `isDeep` is `true` nested objects are cloned,
+     * otherwise they are assigned by reference. If `customizer` is provided it's
+     * invoked to produce the cloned values. If `customizer` returns `undefined`
+     * cloning is handled by the method instead. The `customizer` is bound to
+     * `thisArg` and invoked with up to three argument; (value [, index|key, object]).
+     *
+     * **Note:** This method is loosely based on the
+     * [structured clone algorithm](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm).
+     * The enumerable properties of `arguments` objects and objects created by
+     * constructors other than `Object` are cloned to plain `Object` objects. An
+     * empty object is returned for uncloneable values such as functions, DOM nodes,
+     * Maps, Sets, and WeakMaps.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to clone.
+     * @param {boolean} [isDeep] Specify a deep clone.
+     * @param {Function} [customizer] The function to customize cloning values.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {*} Returns the cloned value.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney' },
+     *   { 'user': 'fred' }
+     * ];
+     *
+     * var shallow = _.clone(users);
+     * shallow[0] === users[0];
+     * // => true
+     *
+     * var deep = _.clone(users, true);
+     * deep[0] === users[0];
+     * // => false
+     *
+     * // using a customizer callback
+     * var el = _.clone(document.body, function(value) {
+     *   if (_.isElement(value)) {
+     *     return value.cloneNode(false);
+     *   }
+     * });
+     *
+     * el === document.body
+     * // => false
+     * el.nodeName
+     * // => BODY
+     * el.childNodes.length;
+     * // => 0
+     */
+    function clone(value, isDeep, customizer, thisArg) {
+      if (isDeep && typeof isDeep != 'boolean' && isIterateeCall(value, isDeep, customizer)) {
+        isDeep = false;
+      }
+      else if (typeof isDeep == 'function') {
+        thisArg = customizer;
+        customizer = isDeep;
+        isDeep = false;
+      }
+      return typeof customizer == 'function'
+        ? baseClone(value, isDeep, bindCallback(customizer, thisArg, 3))
+        : baseClone(value, isDeep);
+    }
+
+    /**
+     * Creates a deep clone of `value`. If `customizer` is provided it's invoked
+     * to produce the cloned values. If `customizer` returns `undefined` cloning
+     * is handled by the method instead. The `customizer` is bound to `thisArg`
+     * and invoked with up to three argument; (value [, index|key, object]).
+     *
+     * **Note:** This method is loosely based on the
+     * [structured clone algorithm](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm).
+     * The enumerable properties of `arguments` objects and objects created by
+     * constructors other than `Object` are cloned to plain `Object` objects. An
+     * empty object is returned for uncloneable values such as functions, DOM nodes,
+     * Maps, Sets, and WeakMaps.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to deep clone.
+     * @param {Function} [customizer] The function to customize cloning values.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {*} Returns the deep cloned value.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney' },
+     *   { 'user': 'fred' }
+     * ];
+     *
+     * var deep = _.cloneDeep(users);
+     * deep[0] === users[0];
+     * // => false
+     *
+     * // using a customizer callback
+     * var el = _.cloneDeep(document.body, function(value) {
+     *   if (_.isElement(value)) {
+     *     return value.cloneNode(true);
+     *   }
+     * });
+     *
+     * el === document.body
+     * // => false
+     * el.nodeName
+     * // => BODY
+     * el.childNodes.length;
+     * // => 20
+     */
+    function cloneDeep(value, customizer, thisArg) {
+      return typeof customizer == 'function'
+        ? baseClone(value, true, bindCallback(customizer, thisArg, 3))
+        : baseClone(value, true);
+    }
+
+    /**
+     * Checks if `value` is greater than `other`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is greater than `other`, else `false`.
+     * @example
+     *
+     * _.gt(3, 1);
+     * // => true
+     *
+     * _.gt(3, 3);
+     * // => false
+     *
+     * _.gt(1, 3);
+     * // => false
+     */
+    function gt(value, other) {
+      return value > other;
+    }
+
+    /**
+     * Checks if `value` is greater than or equal to `other`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is greater than or equal to `other`, else `false`.
+     * @example
+     *
+     * _.gte(3, 1);
+     * // => true
+     *
+     * _.gte(3, 3);
      * // => true
-     */
-    function constant(value) {
-      return function() {
-        return value;
-      };
-    }
-
-    /**
-     * Produces a callback bound to an optional `thisArg`. If `func` is a property
-     * name the created callback will return the property value for a given element.
-     * If `func` is an object the created callback will return `true` for elements
-     * that contain the equivalent object properties, otherwise it will return `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {*} [func=identity] The value to convert to a callback.
-     * @param {*} [thisArg] The `this` binding of the created callback.
-     * @param {number} [argCount] The number of arguments the callback accepts.
-     * @returns {Function} Returns a callback function.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
-     *
-     * // wrap to create custom callback shorthands
-     * _.createCallback = _.wrap(_.createCallback, function(func, callback, thisArg) {
-     *   var match = /^(.+?)__([gl]t)(.+)$/.exec(callback);
-     *   return !match ? func(callback, thisArg) : function(object) {
-     *     return match[2] == 'gt' ? object[match[1]] > match[3] : object[match[1]] < match[3];
-     *   };
+     *
+     * _.gte(1, 3);
+     * // => false
+     */
+    function gte(value, other) {
+      return value >= other;
+    }
+
+    /**
+     * Checks if `value` is classified as an `arguments` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isArguments(function() { return arguments; }());
+     * // => true
+     *
+     * _.isArguments([1, 2, 3]);
+     * // => false
+     */
+    function isArguments(value) {
+      return isObjectLike(value) && isArrayLike(value) &&
+        hasOwnProperty.call(value, 'callee') && !propertyIsEnumerable.call(value, 'callee');
+    }
+
+    /**
+     * Checks if `value` is classified as an `Array` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isArray([1, 2, 3]);
+     * // => true
+     *
+     * _.isArray(function() { return arguments; }());
+     * // => false
+     */
+    var isArray = nativeIsArray || function(value) {
+      return isObjectLike(value) && isLength(value.length) && objToString.call(value) == arrayTag;
+    };
+
+    /**
+     * Checks if `value` is classified as a boolean primitive or object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isBoolean(false);
+     * // => true
+     *
+     * _.isBoolean(null);
+     * // => false
+     */
+    function isBoolean(value) {
+      return value === true || value === false || (isObjectLike(value) && objToString.call(value) == boolTag);
+    }
+
+    /**
+     * Checks if `value` is classified as a `Date` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isDate(new Date);
+     * // => true
+     *
+     * _.isDate('Mon April 23 2012');
+     * // => false
+     */
+    function isDate(value) {
+      return isObjectLike(value) && objToString.call(value) == dateTag;
+    }
+
+    /**
+     * Checks if `value` is a DOM element.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a DOM element, else `false`.
+     * @example
+     *
+     * _.isElement(document.body);
+     * // => true
+     *
+     * _.isElement('<body>');
+     * // => false
+     */
+    function isElement(value) {
+      return !!value && value.nodeType === 1 && isObjectLike(value) && !isPlainObject(value);
+    }
+
+    /**
+     * Checks if `value` is empty. A value is considered empty unless it's an
+     * `arguments` object, array, string, or jQuery-like collection with a length
+     * greater than `0` or an object with own enumerable properties.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {Array|Object|string} value The value to inspect.
+     * @returns {boolean} Returns `true` if `value` is empty, else `false`.
+     * @example
+     *
+     * _.isEmpty(null);
+     * // => true
+     *
+     * _.isEmpty(true);
+     * // => true
+     *
+     * _.isEmpty(1);
+     * // => true
+     *
+     * _.isEmpty([1, 2, 3]);
+     * // => false
+     *
+     * _.isEmpty({ 'a': 1 });
+     * // => false
+     */
+    function isEmpty(value) {
+      if (value == null) {
+        return true;
+      }
+      if (isArrayLike(value) && (isArray(value) || isString(value) || isArguments(value) ||
+          (isObjectLike(value) && isFunction(value.splice)))) {
+        return !value.length;
+      }
+      return !keys(value).length;
+    }
+
+    /**
+     * Performs a deep comparison between two values to determine if they are
+     * equivalent. If `customizer` is provided it's invoked to compare values.
+     * If `customizer` returns `undefined` comparisons are handled by the method
+     * instead. The `customizer` is bound to `thisArg` and invoked with up to
+     * three arguments: (value, other [, index|key]).
+     *
+     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
+     * numbers, `Object` objects, regexes, and strings. Objects are compared by
+     * their own, not inherited, enumerable properties. Functions and DOM nodes
+     * are **not** supported. Provide a customizer function to extend support
+     * for comparing other values.
+     *
+     * @static
+     * @memberOf _
+     * @alias eq
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @param {Function} [customizer] The function to customize value comparisons.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
+     * @example
+     *
+     * var object = { 'user': 'fred' };
+     * var other = { 'user': 'fred' };
+     *
+     * object == other;
+     * // => false
+     *
+     * _.isEqual(object, other);
+     * // => true
+     *
+     * // using a customizer callback
+     * var array = ['hello', 'goodbye'];
+     * var other = ['hi', 'goodbye'];
+     *
+     * _.isEqual(array, other, function(value, other) {
+     *   if (_.every([value, other], RegExp.prototype.test, /^h(?:i|ello)$/)) {
+     *     return true;
+     *   }
      * });
-     *
-     * _.filter(characters, 'age__gt38');
-     * // => [{ 'name': 'fred', 'age': 40 }]
-     */
-    function createCallback(func, thisArg, argCount) {
-      var type = typeof func;
-      if (func == null || type == 'function') {
-        return baseCreateCallback(func, thisArg, argCount);
-      }
-      // handle "_.pluck" style callback shorthands
-      if (type != 'object') {
-        return property(func);
-      }
-      var props = keys(func),
-          key = props[0],
-          a = func[key];
-
-      // handle "_.where" style callback shorthands
-      if (props.length == 1 && a === a && !isObject(a)) {
-        // fast path the common case of providing an object with a single
-        // property containing a primitive value
-        return function(object) {
-          var b = object[key];
-          return a === b && (a !== 0 || (1 / a == 1 / b));
-        };
-      }
-      return function(object) {
-        var length = props.length,
-            result = false;
-
-        while (length--) {
-          if (!(result = baseIsEqual(object[props[length]], func[props[length]], null, true))) {
-            break;
-          }
-        }
-        return result;
-      };
-    }
-
-    /**
-     * Converts the characters `&`, `<`, `>`, `"`, and `'` in `string` to their
-     * corresponding HTML entities.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {string} string The string to escape.
-     * @returns {string} Returns the escaped string.
-     * @example
-     *
-     * _.escape('Fred, Wilma, & Pebbles');
-     * // => 'Fred, Wilma, &amp; Pebbles'
-     */
-    function escape(string) {
-      return string == null ? '' : String(string).replace(reUnescapedHtml, escapeHtmlChar);
-    }
-
-    /**
-     * This method returns the first argument provided to it.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {*} value Any value.
-     * @returns {*} Returns `value`.
-     * @example
-     *
-     * var object = { 'name': 'fred' };
-     * _.identity(object) === object;
+     * // => true
+     */
+    function isEqual(value, other, customizer, thisArg) {
+      customizer = typeof customizer == 'function' ? bindCallback(customizer, thisArg, 3) : undefined;
+      var result = customizer ? customizer(value, other) : undefined;
+      return  result === undefined ? baseIsEqual(value, other, customizer) : !!result;
+    }
+
+    /**
+     * Checks if `value` is an `Error`, `EvalError`, `RangeError`, `ReferenceError`,
+     * `SyntaxError`, `TypeError`, or `URIError` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an error object, else `false`.
+     * @example
+     *
+     * _.isError(new Error);
+     * // => true
+     *
+     * _.isError(Error);
+     * // => false
+     */
+    function isError(value) {
+      return isObjectLike(value) && typeof value.message == 'string' && objToString.call(value) == errorTag;
+    }
+
+    /**
+     * Checks if `value` is a finite primitive number.
+     *
+     * **Note:** This method is based on [`Number.isFinite`](http://ecma-international.org/ecma-262/6.0/#sec-number.isfinite).
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a finite number, else `false`.
+     * @example
+     *
+     * _.isFinite(10);
+     * // => true
+     *
+     * _.isFinite('10');
+     * // => false
+     *
+     * _.isFinite(true);
+     * // => false
+     *
+     * _.isFinite(Object(10));
+     * // => false
+     *
+     * _.isFinite(Infinity);
+     * // => false
+     */
+    function isFinite(value) {
+      return typeof value == 'number' && nativeIsFinite(value);
+    }
+
+    /**
+     * Checks if `value` is classified as a `Function` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isFunction(_);
+     * // => true
+     *
+     * _.isFunction(/abc/);
+     * // => false
+     */
+    function isFunction(value) {
+      // The use of `Object#toString` avoids issues with the `typeof` operator
+      // in older versions of Chrome and Safari which return 'function' for regexes
+      // and Safari 8 which returns 'object' for typed array constructors.
+      return isObject(value) && objToString.call(value) == funcTag;
+    }
+
+    /**
+     * Checks if `value` is the [language type](https://es5.github.io/#x8) of `Object`.
+     * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an object, else `false`.
+     * @example
+     *
+     * _.isObject({});
+     * // => true
+     *
+     * _.isObject([1, 2, 3]);
+     * // => true
+     *
+     * _.isObject(1);
+     * // => false
+     */
+    function isObject(value) {
+      // Avoid a V8 JIT bug in Chrome 19-20.
+      // See https://code.google.com/p/v8/issues/detail?id=2291 for more details.
+      var type = typeof value;
+      return !!value && (type == 'object' || type == 'function');
+    }
+
+    /**
+     * Performs a deep comparison between `object` and `source` to determine if
+     * `object` contains equivalent property values. If `customizer` is provided
+     * it's invoked to compare values. If `customizer` returns `undefined`
+     * comparisons are handled by the method instead. The `customizer` is bound
+     * to `thisArg` and invoked with three arguments: (value, other, index|key).
+     *
+     * **Note:** This method supports comparing properties of arrays, booleans,
+     * `Date` objects, numbers, `Object` objects, regexes, and strings. Functions
+     * and DOM nodes are **not** supported. Provide a customizer function to extend
+     * support for comparing other values.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {Object} object The object to inspect.
+     * @param {Object} source The object of property values to match.
+     * @param {Function} [customizer] The function to customize value comparisons.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {boolean} Returns `true` if `object` is a match, else `false`.
+     * @example
+     *
+     * var object = { 'user': 'fred', 'age': 40 };
+     *
+     * _.isMatch(object, { 'age': 40 });
+     * // => true
+     *
+     * _.isMatch(object, { 'age': 36 });
+     * // => false
+     *
+     * // using a customizer callback
+     * var object = { 'greeting': 'hello' };
+     * var source = { 'greeting': 'hi' };
+     *
+     * _.isMatch(object, source, function(value, other) {
+     *   return _.every([value, other], RegExp.prototype.test, /^h(?:i|ello)$/) || undefined;
+     * });
+     * // => true
+     */
+    function isMatch(object, source, customizer, thisArg) {
+      customizer = typeof customizer == 'function' ? bindCallback(customizer, thisArg, 3) : undefined;
+      return baseIsMatch(object, getMatchData(source), customizer);
+    }
+
+    /**
+     * Checks if `value` is `NaN`.
+     *
+     * **Note:** This method is not the same as [`isNaN`](https://es5.github.io/#x15.1.2.4)
+     * which returns `true` for `undefined` and other non-numeric values.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.
+     * @example
+     *
+     * _.isNaN(NaN);
+     * // => true
+     *
+     * _.isNaN(new Number(NaN));
+     * // => true
+     *
+     * isNaN(undefined);
+     * // => true
+     *
+     * _.isNaN(undefined);
+     * // => false
+     */
+    function isNaN(value) {
+      // An `NaN` primitive is the only value that is not equal to itself.
+      // Perform the `toStringTag` check first to avoid errors with some host objects in IE.
+      return isNumber(value) && value != +value;
+    }
+
+    /**
+     * Checks if `value` is a native function.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a native function, else `false`.
+     * @example
+     *
+     * _.isNative(Array.prototype.push);
+     * // => true
+     *
+     * _.isNative(_);
+     * // => false
+     */
+    function isNative(value) {
+      if (value == null) {
+        return false;
+      }
+      if (isFunction(value)) {
+        return reIsNative.test(fnToString.call(value));
+      }
+      return isObjectLike(value) && reIsHostCtor.test(value);
+    }
+
+    /**
+     * Checks if `value` is `null`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is `null`, else `false`.
+     * @example
+     *
+     * _.isNull(null);
      * // => true
-     */
-    function identity(value) {
-      return value;
-    }
-
-    /**
-     * Adds function properties of a source object to the destination object.
-     * If `object` is a function methods will be added to its prototype as well.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {Function|Object} [object=lodash] object The destination object.
-     * @param {Object} source The object of functions to add.
-     * @param {Object} [options] The options object.
-     * @param {boolean} [options.chain=true] Specify whether the functions added are chainable.
-     * @example
-     *
-     * function capitalize(string) {
-     *   return string.charAt(0).toUpperCase() + string.slice(1).toLowerCase();
+     *
+     * _.isNull(void 0);
+     * // => false
+     */
+    function isNull(value) {
+      return value === null;
+    }
+
+    /**
+     * Checks if `value` is classified as a `Number` primitive or object.
+     *
+     * **Note:** To exclude `Infinity`, `-Infinity`, and `NaN`, which are classified
+     * as numbers, use the `_.isFinite` method.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isNumber(8.4);
+     * // => true
+     *
+     * _.isNumber(NaN);
+     * // => true
+     *
+     * _.isNumber('8.4');
+     * // => false
+     */
+    function isNumber(value) {
+      return typeof value == 'number' || (isObjectLike(value) && objToString.call(value) == numberTag);
+    }
+
+    /**
+     * Checks if `value` is a plain object, that is, an object created by the
+     * `Object` constructor or one with a `[[Prototype]]` of `null`.
+     *
+     * **Note:** This method assumes objects created by the `Object` constructor
+     * have no inherited enumerable properties.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     * }
+     *
+     * _.isPlainObject(new Foo);
+     * // => false
+     *
+     * _.isPlainObject([1, 2, 3]);
+     * // => false
+     *
+     * _.isPlainObject({ 'x': 0, 'y': 0 });
+     * // => true
+     *
+     * _.isPlainObject(Object.create(null));
+     * // => true
+     */
+    function isPlainObject(value) {
+      var Ctor;
+
+      // Exit early for non `Object` objects.
+      if (!(isObjectLike(value) && objToString.call(value) == objectTag && !isArguments(value)) ||
+          (!hasOwnProperty.call(value, 'constructor') && (Ctor = value.constructor, typeof Ctor == 'function' && !(Ctor instanceof Ctor)))) {
+        return false;
+      }
+      // IE < 9 iterates inherited properties before own properties. If the first
+      // iterated property is an object's own property then there are no inherited
+      // enumerable properties.
+      var result;
+      // In most environments an object's own properties are iterated before
+      // its inherited properties. If the last iterated property is an object's
+      // own property then there are no inherited enumerable properties.
+      baseForIn(value, function(subValue, key) {
+        result = key;
+      });
+      return result === undefined || hasOwnProperty.call(value, result);
+    }
+
+    /**
+     * Checks if `value` is classified as a `RegExp` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isRegExp(/abc/);
+     * // => true
+     *
+     * _.isRegExp('/abc/');
+     * // => false
+     */
+    function isRegExp(value) {
+      return isObject(value) && objToString.call(value) == regexpTag;
+    }
+
+    /**
+     * Checks if `value` is classified as a `String` primitive or object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isString('abc');
+     * // => true
+     *
+     * _.isString(1);
+     * // => false
+     */
+    function isString(value) {
+      return typeof value == 'string' || (isObjectLike(value) && objToString.call(value) == stringTag);
+    }
+
+    /**
+     * Checks if `value` is classified as a typed array.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isTypedArray(new Uint8Array);
+     * // => true
+     *
+     * _.isTypedArray([]);
+     * // => false
+     */
+    function isTypedArray(value) {
+      return isObjectLike(value) && isLength(value.length) && !!typedArrayTags[objToString.call(value)];
+    }
+
+    /**
+     * Checks if `value` is `undefined`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is `undefined`, else `false`.
+     * @example
+     *
+     * _.isUndefined(void 0);
+     * // => true
+     *
+     * _.isUndefined(null);
+     * // => false
+     */
+    function isUndefined(value) {
+      return value === undefined;
+    }
+
+    /**
+     * Checks if `value` is less than `other`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is less than `other`, else `false`.
+     * @example
+     *
+     * _.lt(1, 3);
+     * // => true
+     *
+     * _.lt(3, 3);
+     * // => false
+     *
+     * _.lt(3, 1);
+     * // => false
+     */
+    function lt(value, other) {
+      return value < other;
+    }
+
+    /**
+     * Checks if `value` is less than or equal to `other`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is less than or equal to `other`, else `false`.
+     * @example
+     *
+     * _.lte(1, 3);
+     * // => true
+     *
+     * _.lte(3, 3);
+     * // => true
+     *
+     * _.lte(3, 1);
+     * // => false
+     */
+    function lte(value, other) {
+      return value <= other;
+    }
+
+    /**
+     * Converts `value` to an array.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to convert.
+     * @returns {Array} Returns the converted array.
+     * @example
+     *
+     * (function() {
+     *   return _.toArray(arguments).slice(1);
+     * }(1, 2, 3));
+     * // => [2, 3]
+     */
+    function toArray(value) {
+      var length = value ? getLength(value) : 0;
+      if (!isLength(length)) {
+        return values(value);
+      }
+      if (!length) {
+        return [];
+      }
+      return arrayCopy(value);
+    }
+
+    /**
+     * Converts `value` to a plain object flattening inherited enumerable
+     * properties of `value` to own properties of the plain object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to convert.
+     * @returns {Object} Returns the converted plain object.
+     * @example
+     *
+     * function Foo() {
+     *   this.b = 2;
      * }
      *
-     * _.mixin({ 'capitalize': capitalize });
-     * _.capitalize('fred');
-     * // => 'Fred'
-     *
-     * _('fred').capitalize().value();
-     * // => 'Fred'
-     *
-     * _.mixin({ 'capitalize': capitalize }, { 'chain': false });
-     * _('fred').capitalize();
-     * // => 'Fred'
-     */
-    function mixin(object, source, options) {
-      var chain = true,
-          methodNames = source && functions(source);
-
-      if (!source || (!options && !methodNames.length)) {
-        if (options == null) {
-          options = source;
-        }
-        ctor = lodashWrapper;
-        source = object;
-        object = lodash;
-        methodNames = functions(source);
-      }
-      if (options === false) {
-        chain = false;
-      } else if (isObject(options) && 'chain' in options) {
-        chain = options.chain;
-      }
-      var ctor = object,
-          isFunc = isFunction(ctor);
-
-      forEach(methodNames, function(methodName) {
-        var func = object[methodName] = source[methodName];
-        if (isFunc) {
-          ctor.prototype[methodName] = function() {
-            var chainAll = this.__chain__,
-                value = this.__wrapped__,
-                args = [value];
-
-            push.apply(args, arguments);
-            var result = func.apply(object, args);
-            if (chain || chainAll) {
-              if (value === result && isObject(result)) {
-                return this;
-              }
-              result = new ctor(result);
-              result.__chain__ = chainAll;
-            }
-            return result;
-          };
-        }
+     * Foo.prototype.c = 3;
+     *
+     * _.assign({ 'a': 1 }, new Foo);
+     * // => { 'a': 1, 'b': 2 }
+     *
+     * _.assign({ 'a': 1 }, _.toPlainObject(new Foo));
+     * // => { 'a': 1, 'b': 2, 'c': 3 }
+     */
+    function toPlainObject(value) {
+      return baseCopy(value, keysIn(value));
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Recursively merges own enumerable properties of the source object(s), that
+     * don't resolve to `undefined` into the destination object. Subsequent sources
+     * overwrite property assignments of previous sources. If `customizer` is
+     * provided it's invoked to produce the merged values of the destination and
+     * source properties. If `customizer` returns `undefined` merging is handled
+     * by the method instead. The `customizer` is bound to `thisArg` and invoked
+     * with five arguments: (objectValue, sourceValue, key, object, source).
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @param {Function} [customizer] The function to customize assigned values.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * var users = {
+     *   'data': [{ 'user': 'barney' }, { 'user': 'fred' }]
+     * };
+     *
+     * var ages = {
+     *   'data': [{ 'age': 36 }, { 'age': 40 }]
+     * };
+     *
+     * _.merge(users, ages);
+     * // => { 'data': [{ 'user': 'barney', 'age': 36 }, { 'user': 'fred', 'age': 40 }] }
+     *
+     * // using a customizer callback
+     * var object = {
+     *   'fruits': ['apple'],
+     *   'vegetables': ['beet']
+     * };
+     *
+     * var other = {
+     *   'fruits': ['banana'],
+     *   'vegetables': ['carrot']
+     * };
+     *
+     * _.merge(object, other, function(a, b) {
+     *   if (_.isArray(a)) {
+     *     return a.concat(b);
+     *   }
+     * });
+     * // => { 'fruits': ['apple', 'banana'], 'vegetables': ['beet', 'carrot'] }
+     */
+    var merge = createAssigner(baseMerge);
+
+    /**
+     * Assigns own enumerable properties of source object(s) to the destination
+     * object. Subsequent sources overwrite property assignments of previous sources.
+     * If `customizer` is provided it's invoked to produce the assigned values.
+     * The `customizer` is bound to `thisArg` and invoked with five arguments:
+     * (objectValue, sourceValue, key, object, source).
+     *
+     * **Note:** This method mutates `object` and is based on
+     * [`Object.assign`](http://ecma-international.org/ecma-262/6.0/#sec-object.assign).
+     *
+     * @static
+     * @memberOf _
+     * @alias extend
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @param {Function} [customizer] The function to customize assigned values.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * _.assign({ 'user': 'barney' }, { 'age': 40 }, { 'user': 'fred' });
+     * // => { 'user': 'fred', 'age': 40 }
+     *
+     * // using a customizer callback
+     * var defaults = _.partialRight(_.assign, function(value, other) {
+     *   return _.isUndefined(value) ? other : value;
+     * });
+     *
+     * defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred' });
+     * // => { 'user': 'barney', 'age': 36 }
+     */
+    var assign = createAssigner(function(object, source, customizer) {
+      return customizer
+        ? assignWith(object, source, customizer)
+        : baseAssign(object, source);
+    });
+
+    /**
+     * Creates an object that inherits from the given `prototype` object. If a
+     * `properties` object is provided its own enumerable properties are assigned
+     * to the created object.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} prototype The object to inherit from.
+     * @param {Object} [properties] The properties to assign to the object.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Object} Returns the new object.
+     * @example
+     *
+     * function Shape() {
+     *   this.x = 0;
+     *   this.y = 0;
+     * }
+     *
+     * function Circle() {
+     *   Shape.call(this);
+     * }
+     *
+     * Circle.prototype = _.create(Shape.prototype, {
+     *   'constructor': Circle
+     * });
+     *
+     * var circle = new Circle;
+     * circle instanceof Circle;
+     * // => true
+     *
+     * circle instanceof Shape;
+     * // => true
+     */
+    function create(prototype, properties, guard) {
+      var result = baseCreate(prototype);
+      if (guard && isIterateeCall(prototype, properties, guard)) {
+        properties = undefined;
+      }
+      return properties ? baseAssign(result, properties) : result;
+    }
+
+    /**
+     * Assigns own enumerable properties of source object(s) to the destination
+     * object for all destination properties that resolve to `undefined`. Once a
+     * property is set, additional values of the same property are ignored.
+     *
+     * **Note:** This method mutates `object`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * _.defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred' });
+     * // => { 'user': 'barney', 'age': 36 }
+     */
+    var defaults = createDefaults(assign, assignDefaults);
+
+    /**
+     * This method is like `_.defaults` except that it recursively assigns
+     * default properties.
+     *
+     * **Note:** This method mutates `object`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * _.defaultsDeep({ 'user': { 'name': 'barney' } }, { 'user': { 'name': 'fred', 'age': 36 } });
+     * // => { 'user': { 'name': 'barney', 'age': 36 } }
+     *
+     */
+    var defaultsDeep = createDefaults(merge, mergeDefaults);
+
+    /**
+     * This method is like `_.find` except that it returns the key of the first
+     * element `predicate` returns truthy for instead of the element itself.
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {string|undefined} Returns the key of the matched element, else `undefined`.
+     * @example
+     *
+     * var users = {
+     *   'barney':  { 'age': 36, 'active': true },
+     *   'fred':    { 'age': 40, 'active': false },
+     *   'pebbles': { 'age': 1,  'active': true }
+     * };
+     *
+     * _.findKey(users, function(chr) {
+     *   return chr.age < 40;
+     * });
+     * // => 'barney' (iteration order is not guaranteed)
+     *
+     * // using the `_.matches` callback shorthand
+     * _.findKey(users, { 'age': 1, 'active': true });
+     * // => 'pebbles'
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.findKey(users, 'active', false);
+     * // => 'fred'
+     *
+     * // using the `_.property` callback shorthand
+     * _.findKey(users, 'active');
+     * // => 'barney'
+     */
+    var findKey = createFindKey(baseForOwn);
+
+    /**
+     * This method is like `_.findKey` except that it iterates over elements of
+     * a collection in the opposite order.
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {string|undefined} Returns the key of the matched element, else `undefined`.
+     * @example
+     *
+     * var users = {
+     *   'barney':  { 'age': 36, 'active': true },
+     *   'fred':    { 'age': 40, 'active': false },
+     *   'pebbles': { 'age': 1,  'active': true }
+     * };
+     *
+     * _.findLastKey(users, function(chr) {
+     *   return chr.age < 40;
+     * });
+     * // => returns `pebbles` assuming `_.findKey` returns `barney`
+     *
+     * // using the `_.matches` callback shorthand
+     * _.findLastKey(users, { 'age': 36, 'active': true });
+     * // => 'barney'
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.findLastKey(users, 'active', false);
+     * // => 'fred'
+     *
+     * // using the `_.property` callback shorthand
+     * _.findLastKey(users, 'active');
+     * // => 'pebbles'
+     */
+    var findLastKey = createFindKey(baseForOwnRight);
+
+    /**
+     * Iterates over own and inherited enumerable properties of an object invoking
+     * `iteratee` for each property. The `iteratee` is bound to `thisArg` and invoked
+     * with three arguments: (value, key, object). Iteratee functions may exit
+     * iteration early by explicitly returning `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.forIn(new Foo, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => logs 'a', 'b', and 'c' (iteration order is not guaranteed)
+     */
+    var forIn = createForIn(baseFor);
+
+    /**
+     * This method is like `_.forIn` except that it iterates over properties of
+     * `object` in the opposite order.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.forInRight(new Foo, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => logs 'c', 'b', and 'a' assuming `_.forIn ` logs 'a', 'b', and 'c'
+     */
+    var forInRight = createForIn(baseForRight);
+
+    /**
+     * Iterates over own enumerable properties of an object invoking `iteratee`
+     * for each property. The `iteratee` is bound to `thisArg` and invoked with
+     * three arguments: (value, key, object). Iteratee functions may exit iteration
+     * early by explicitly returning `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.forOwn(new Foo, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => logs 'a' and 'b' (iteration order is not guaranteed)
+     */
+    var forOwn = createForOwn(baseForOwn);
+
+    /**
+     * This method is like `_.forOwn` except that it iterates over properties of
+     * `object` in the opposite order.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.forOwnRight(new Foo, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => logs 'b' and 'a' assuming `_.forOwn` logs 'a' and 'b'
+     */
+    var forOwnRight = createForOwn(baseForOwnRight);
+
+    /**
+     * Creates an array of function property names from all enumerable properties,
+     * own and inherited, of `object`.
+     *
+     * @static
+     * @memberOf _
+     * @alias methods
+     * @category Object
+     * @param {Object} object The object to inspect.
+     * @returns {Array} Returns the new array of property names.
+     * @example
+     *
+     * _.functions(_);
+     * // => ['after', 'ary', 'assign', ...]
+     */
+    function functions(object) {
+      return baseFunctions(object, keysIn(object));
+    }
+
+    /**
+     * Gets the property value at `path` of `object`. If the resolved value is
+     * `undefined` the `defaultValue` is used in its place.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the property to get.
+     * @param {*} [defaultValue] The value returned if the resolved value is `undefined`.
+     * @returns {*} Returns the resolved value.
+     * @example
+     *
+     * var object = { 'a': [{ 'b': { 'c': 3 } }] };
+     *
+     * _.get(object, 'a[0].b.c');
+     * // => 3
+     *
+     * _.get(object, ['a', '0', 'b', 'c']);
+     * // => 3
+     *
+     * _.get(object, 'a.b.c', 'default');
+     * // => 'default'
+     */
+    function get(object, path, defaultValue) {
+      var result = object == null ? undefined : baseGet(object, toPath(path), (path + ''));
+      return result === undefined ? defaultValue : result;
+    }
+
+    /**
+     * Checks if `path` is a direct property.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path to check.
+     * @returns {boolean} Returns `true` if `path` is a direct property, else `false`.
+     * @example
+     *
+     * var object = { 'a': { 'b': { 'c': 3 } } };
+     *
+     * _.has(object, 'a');
+     * // => true
+     *
+     * _.has(object, 'a.b.c');
+     * // => true
+     *
+     * _.has(object, ['a', 'b', 'c']);
+     * // => true
+     */
+    function has(object, path) {
+      if (object == null) {
+        return false;
+      }
+      var result = hasOwnProperty.call(object, path);
+      if (!result && !isKey(path)) {
+        path = toPath(path);
+        object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+        if (object == null) {
+          return false;
+        }
+        path = last(path);
+        result = hasOwnProperty.call(object, path);
+      }
+      return result || (isLength(object.length) && isIndex(path, object.length) &&
+        (isArray(object) || isArguments(object)));
+    }
+
+    /**
+     * Creates an object composed of the inverted keys and values of `object`.
+     * If `object` contains duplicate values, subsequent values overwrite property
+     * assignments of previous values unless `multiValue` is `true`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to invert.
+     * @param {boolean} [multiValue] Allow multiple values per key.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Object} Returns the new inverted object.
+     * @example
+     *
+     * var object = { 'a': 1, 'b': 2, 'c': 1 };
+     *
+     * _.invert(object);
+     * // => { '1': 'c', '2': 'b' }
+     *
+     * // with `multiValue`
+     * _.invert(object, true);
+     * // => { '1': ['a', 'c'], '2': ['b'] }
+     */
+    function invert(object, multiValue, guard) {
+      if (guard && isIterateeCall(object, multiValue, guard)) {
+        multiValue = undefined;
+      }
+      var index = -1,
+          props = keys(object),
+          length = props.length,
+          result = {};
+
+      while (++index < length) {
+        var key = props[index],
+            value = object[key];
+
+        if (multiValue) {
+          if (hasOwnProperty.call(result, value)) {
+            result[value].push(key);
+          } else {
+            result[value] = [key];
+          }
+        }
+        else {
+          result[value] = key;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Creates an array of the own enumerable property names of `object`.
+     *
+     * **Note:** Non-object values are coerced to objects. See the
+     * [ES spec](http://ecma-international.org/ecma-262/6.0/#sec-object.keys)
+     * for more details.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.keys(new Foo);
+     * // => ['a', 'b'] (iteration order is not guaranteed)
+     *
+     * _.keys('hi');
+     * // => ['0', '1']
+     */
+    var keys = !nativeKeys ? shimKeys : function(object) {
+      var Ctor = object == null ? undefined : object.constructor;
+      if ((typeof Ctor == 'function' && Ctor.prototype === object) ||
+          (typeof object != 'function' && isArrayLike(object))) {
+        return shimKeys(object);
+      }
+      return isObject(object) ? nativeKeys(object) : [];
+    };
+
+    /**
+     * Creates an array of the own and inherited enumerable property names of `object`.
+     *
+     * **Note:** Non-object values are coerced to objects.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.keysIn(new Foo);
+     * // => ['a', 'b', 'c'] (iteration order is not guaranteed)
+     */
+    function keysIn(object) {
+      if (object == null) {
+        return [];
+      }
+      if (!isObject(object)) {
+        object = Object(object);
+      }
+      var length = object.length;
+      length = (length && isLength(length) &&
+        (isArray(object) || isArguments(object)) && length) || 0;
+
+      var Ctor = object.constructor,
+          index = -1,
+          isProto = typeof Ctor == 'function' && Ctor.prototype === object,
+          result = Array(length),
+          skipIndexes = length > 0;
+
+      while (++index < length) {
+        result[index] = (index + '');
+      }
+      for (var key in object) {
+        if (!(skipIndexes && isIndex(key, length)) &&
+            !(key == 'constructor' && (isProto || !hasOwnProperty.call(object, key)))) {
+          result.push(key);
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The opposite of `_.mapValues`; this method creates an object with the
+     * same values as `object` and keys generated by running each own enumerable
+     * property of `object` through `iteratee`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns the new mapped object.
+     * @example
+     *
+     * _.mapKeys({ 'a': 1, 'b': 2 }, function(value, key) {
+     *   return key + value;
+     * });
+     * // => { 'a1': 1, 'b2': 2 }
+     */
+    var mapKeys = createObjectMapper(true);
+
+    /**
+     * Creates an object with the same keys as `object` and values generated by
+     * running each own enumerable property of `object` through `iteratee`. The
+     * iteratee function is bound to `thisArg` and invoked with three arguments:
+     * (value, key, object).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns the new mapped object.
+     * @example
+     *
+     * _.mapValues({ 'a': 1, 'b': 2 }, function(n) {
+     *   return n * 3;
+     * });
+     * // => { 'a': 3, 'b': 6 }
+     *
+     * var users = {
+     *   'fred':    { 'user': 'fred',    'age': 40 },
+     *   'pebbles': { 'user': 'pebbles', 'age': 1 }
+     * };
+     *
+     * // using the `_.property` callback shorthand
+     * _.mapValues(users, 'age');
+     * // => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)
+     */
+    var mapValues = createObjectMapper();
+
+    /**
+     * The opposite of `_.pick`; this method creates an object composed of the
+     * own and inherited enumerable properties of `object` that are not omitted.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The source object.
+     * @param {Function|...(string|string[])} [predicate] The function invoked per
+     *  iteration or property names to omit, specified as individual property
+     *  names or arrays of property names.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Object} Returns the new object.
+     * @example
+     *
+     * var object = { 'user': 'fred', 'age': 40 };
+     *
+     * _.omit(object, 'age');
+     * // => { 'user': 'fred' }
+     *
+     * _.omit(object, _.isNumber);
+     * // => { 'user': 'fred' }
+     */
+    var omit = restParam(function(object, props) {
+      if (object == null) {
+        return {};
+      }
+      if (typeof props[0] != 'function') {
+        var props = arrayMap(baseFlatten(props), String);
+        return pickByArray(object, baseDifference(keysIn(object), props));
+      }
+      var predicate = bindCallback(props[0], props[1], 3);
+      return pickByCallback(object, function(value, key, object) {
+        return !predicate(value, key, object);
       });
-    }
-
-    /**
-     * Reverts the '_' variable to its previous value and returns a reference to
-     * the `lodash` function.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @returns {Function} Returns the `lodash` function.
-     * @example
-     *
-     * var lodash = _.noConflict();
-     */
-    function noConflict() {
-      context._ = oldDash;
-      return this;
-    }
-
-    /**
-     * A no-operation function.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @example
-     *
-     * var object = { 'name': 'fred' };
-     * _.noop(object) === undefined;
+    });
+
+    /**
+     * Creates a two dimensional array of the key-value pairs for `object`,
+     * e.g. `[[key1, value1], [key2, value2]]`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the new array of key-value pairs.
+     * @example
+     *
+     * _.pairs({ 'barney': 36, 'fred': 40 });
+     * // => [['barney', 36], ['fred', 40]] (iteration order is not guaranteed)
+     */
+    function pairs(object) {
+      object = toObject(object);
+
+      var index = -1,
+          props = keys(object),
+          length = props.length,
+          result = Array(length);
+
+      while (++index < length) {
+        var key = props[index];
+        result[index] = [key, object[key]];
+      }
+      return result;
+    }
+
+    /**
+     * Creates an object composed of the picked `object` properties. Property
+     * names may be specified as individual arguments or as arrays of property
+     * names. If `predicate` is provided it's invoked for each property of `object`
+     * picking the properties `predicate` returns truthy for. The predicate is
+     * bound to `thisArg` and invoked with three arguments: (value, key, object).
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The source object.
+     * @param {Function|...(string|string[])} [predicate] The function invoked per
+     *  iteration or property names to pick, specified as individual property
+     *  names or arrays of property names.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Object} Returns the new object.
+     * @example
+     *
+     * var object = { 'user': 'fred', 'age': 40 };
+     *
+     * _.pick(object, 'user');
+     * // => { 'user': 'fred' }
+     *
+     * _.pick(object, _.isString);
+     * // => { 'user': 'fred' }
+     */
+    var pick = restParam(function(object, props) {
+      if (object == null) {
+        return {};
+      }
+      return typeof props[0] == 'function'
+        ? pickByCallback(object, bindCallback(props[0], props[1], 3))
+        : pickByArray(object, baseFlatten(props));
+    });
+
+    /**
+     * This method is like `_.get` except that if the resolved value is a function
+     * it's invoked with the `this` binding of its parent object and its result
+     * is returned.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the property to resolve.
+     * @param {*} [defaultValue] The value returned if the resolved value is `undefined`.
+     * @returns {*} Returns the resolved value.
+     * @example
+     *
+     * var object = { 'a': [{ 'b': { 'c1': 3, 'c2': _.constant(4) } }] };
+     *
+     * _.result(object, 'a[0].b.c1');
+     * // => 3
+     *
+     * _.result(object, 'a[0].b.c2');
+     * // => 4
+     *
+     * _.result(object, 'a.b.c', 'default');
+     * // => 'default'
+     *
+     * _.result(object, 'a.b.c', _.constant('default'));
+     * // => 'default'
+     */
+    function result(object, path, defaultValue) {
+      var result = object == null ? undefined : object[path];
+      if (result === undefined) {
+        if (object != null && !isKey(path, object)) {
+          path = toPath(path);
+          object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+          result = object == null ? undefined : object[last(path)];
+        }
+        result = result === undefined ? defaultValue : result;
+      }
+      return isFunction(result) ? result.call(object) : result;
+    }
+
+    /**
+     * Sets the property value of `path` on `object`. If a portion of `path`
+     * does not exist it's created.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to augment.
+     * @param {Array|string} path The path of the property to set.
+     * @param {*} value The value to set.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * var object = { 'a': [{ 'b': { 'c': 3 } }] };
+     *
+     * _.set(object, 'a[0].b.c', 4);
+     * console.log(object.a[0].b.c);
+     * // => 4
+     *
+     * _.set(object, 'x[0].y.z', 5);
+     * console.log(object.x[0].y.z);
+     * // => 5
+     */
+    function set(object, path, value) {
+      if (object == null) {
+        return object;
+      }
+      var pathKey = (path + '');
+      path = (object[pathKey] != null || isKey(path, object)) ? [pathKey] : toPath(path);
+
+      var index = -1,
+          length = path.length,
+          lastIndex = length - 1,
+          nested = object;
+
+      while (nested != null && ++index < length) {
+        var key = path[index];
+        if (isObject(nested)) {
+          if (index == lastIndex) {
+            nested[key] = value;
+          } else if (nested[key] == null) {
+            nested[key] = isIndex(path[index + 1]) ? [] : {};
+          }
+        }
+        nested = nested[key];
+      }
+      return object;
+    }
+
+    /**
+     * An alternative to `_.reduce`; this method transforms `object` to a new
+     * `accumulator` object which is the result of running each of its own enumerable
+     * properties through `iteratee`, with each invocation potentially mutating
+     * the `accumulator` object. The `iteratee` is bound to `thisArg` and invoked
+     * with four arguments: (accumulator, value, key, object). Iteratee functions
+     * may exit iteration early by explicitly returning `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Array|Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [accumulator] The custom accumulator value.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {*} Returns the accumulated value.
+     * @example
+     *
+     * _.transform([2, 3, 4], function(result, n) {
+     *   result.push(n *= n);
+     *   return n % 2 == 0;
+     * });
+     * // => [4, 9]
+     *
+     * _.transform({ 'a': 1, 'b': 2 }, function(result, n, key) {
+     *   result[key] = n * 3;
+     * });
+     * // => { 'a': 3, 'b': 6 }
+     */
+    function transform(object, iteratee, accumulator, thisArg) {
+      var isArr = isArray(object) || isTypedArray(object);
+      iteratee = getCallback(iteratee, thisArg, 4);
+
+      if (accumulator == null) {
+        if (isArr || isObject(object)) {
+          var Ctor = object.constructor;
+          if (isArr) {
+            accumulator = isArray(object) ? new Ctor : [];
+          } else {
+            accumulator = baseCreate(isFunction(Ctor) ? Ctor.prototype : undefined);
+          }
+        } else {
+          accumulator = {};
+        }
+      }
+      (isArr ? arrayEach : baseForOwn)(object, function(value, index, object) {
+        return iteratee(accumulator, value, index, object);
+      });
+      return accumulator;
+    }
+
+    /**
+     * Creates an array of the own enumerable property values of `object`.
+     *
+     * **Note:** Non-object values are coerced to objects.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property values.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.values(new Foo);
+     * // => [1, 2] (iteration order is not guaranteed)
+     *
+     * _.values('hi');
+     * // => ['h', 'i']
+     */
+    function values(object) {
+      return baseValues(object, keys(object));
+    }
+
+    /**
+     * Creates an array of the own and inherited enumerable property values
+     * of `object`.
+     *
+     * **Note:** Non-object values are coerced to objects.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property values.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.valuesIn(new Foo);
+     * // => [1, 2, 3] (iteration order is not guaranteed)
+     */
+    function valuesIn(object) {
+      return baseValues(object, keysIn(object));
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Checks if `n` is between `start` and up to but not including, `end`. If
+     * `end` is not specified it's set to `start` with `start` then set to `0`.
+     *
+     * @static
+     * @memberOf _
+     * @category Number
+     * @param {number} n The number to check.
+     * @param {number} [start=0] The start of the range.
+     * @param {number} end The end of the range.
+     * @returns {boolean} Returns `true` if `n` is in the range, else `false`.
+     * @example
+     *
+     * _.inRange(3, 2, 4);
      * // => true
-     */
-    function noop() {
-      // no operation performed
-    }
-
-    /**
-     * Gets the number of milliseconds that have elapsed since the Unix epoch
-     * (1 January 1970 00:00:00 UTC).
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @example
-     *
-     * var stamp = _.now();
-     * _.defer(function() { console.log(_.now() - stamp); });
-     * // => logs the number of milliseconds it took for the deferred function to be called
-     */
-    var now = isNative(now = Date.now) && now || function() {
-      return new Date().getTime();
-    };
-
-    /**
-     * Converts the given value into an integer of the specified radix.
-     * If `radix` is `undefined` or `0` a `radix` of `10` is used unless the
-     * `value` is a hexadecimal, in which case a `radix` of `16` is used.
-     *
-     * Note: This method avoids differences in native ES3 and ES5 `parseInt`
-     * implementations. See http://es5.github.io/#E.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {string} value The value to parse.
-     * @param {number} [radix] The radix used to interpret the value to parse.
-     * @returns {number} Returns the new integer value.
-     * @example
-     *
-     * _.parseInt('08');
-     * // => 8
-     */
-    var parseInt = nativeParseInt(whitespace + '08') == 8 ? nativeParseInt : function(value, radix) {
-      // Firefox < 21 and Opera < 15 follow the ES3 specified implementation of `parseInt`
-      return nativeParseInt(isString(value) ? value.replace(reLeadingSpacesAndZeros, '') : value, radix || 0);
-    };
-
-    /**
-     * Creates a "_.pluck" style function, which returns the `key` value of a
-     * given object.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {string} key The name of the property to retrieve.
-     * @returns {Function} Returns the new function.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'fred',   'age': 40 },
-     *   { 'name': 'barney', 'age': 36 }
-     * ];
-     *
-     * var getName = _.property('name');
-     *
-     * _.map(characters, getName);
-     * // => ['barney', 'fred']
-     *
-     * _.sortBy(characters, getName);
-     * // => [{ 'name': 'barney', 'age': 36 }, { 'name': 'fred',   'age': 40 }]
-     */
-    function property(key) {
-      return function(object) {
-        return object[key];
-      };
+     *
+     * _.inRange(4, 8);
+     * // => true
+     *
+     * _.inRange(4, 2);
+     * // => false
+     *
+     * _.inRange(2, 2);
+     * // => false
+     *
+     * _.inRange(1.2, 2);
+     * // => true
+     *
+     * _.inRange(5.2, 4);
+     * // => false
+     */
+    function inRange(value, start, end) {
+      start = +start || 0;
+      if (end === undefined) {
+        end = start;
+        start = 0;
+      } else {
+        end = +end || 0;
+      }
+      return value >= nativeMin(start, end) && value < nativeMax(start, end);
     }
 
     /**
      * Produces a random number between `min` and `max` (inclusive). If only one
-     * argument is provided a number between `0` and the given number will be
-     * returned. If `floating` is truey or either `min` or `max` are floats a
-     * floating-point number will be returned instead of an integer.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
+     * argument is provided a number between `0` and the given number is returned.
+     * If `floating` is `true`, or either `min` or `max` are floats, a floating-point
+     * number is returned instead of an integer.
+     *
+     * @static
+     * @memberOf _
+     * @category Number
      * @param {number} [min=0] The minimum possible value.
      * @param {number} [max=1] The maximum possible value.
-     * @param {boolean} [floating=false] Specify returning a floating-point number.
-     * @returns {number} Returns a random number.
+     * @param {boolean} [floating] Specify returning a floating-point number.
+     * @returns {number} Returns the random number.
      * @example
      *
      * _.random(0, 5);
@@ -6068,21 +10164,25 @@
      * // => a floating-point number between 1.2 and 5.2
      */
     function random(min, max, floating) {
+      if (floating && isIterateeCall(min, max, floating)) {
+        max = floating = undefined;
+      }
       var noMin = min == null,
           noMax = max == null;
 
       if (floating == null) {
-        if (typeof min == 'boolean' && noMax) {
+        if (noMax && typeof min == 'boolean') {
           floating = min;
           min = 1;
         }
-        else if (!noMax && typeof max == 'boolean') {
+        else if (typeof max == 'boolean') {
           floating = max;
           noMax = true;
         }
       }
       if (noMin && noMax) {
         max = 1;
+        noMax = false;
       }
       min = +min || 0;
       if (noMax) {
@@ -6093,122 +10193,517 @@
       }
       if (floating || min % 1 || max % 1) {
         var rand = nativeRandom();
-        return nativeMin(min + (rand * (max - min + parseFloat('1e-' + ((rand +'').length - 1)))), max);
+        return nativeMin(min + (rand * (max - min + parseFloat('1e-' + ((rand + '').length - 1)))), max);
       }
       return baseRandom(min, max);
     }
 
-    /**
-     * Resolves the value of property `key` on `object`. If `key` is a function
-     * it will be invoked with the `this` binding of `object` and its result returned,
-     * else the property value is returned. If `object` is falsey then `undefined`
-     * is returned.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {Object} object The object to inspect.
-     * @param {string} key The name of the property to resolve.
-     * @returns {*} Returns the resolved value.
-     * @example
-     *
-     * var object = {
-     *   'cheese': 'crumpets',
-     *   'stuff': function() {
-     *     return 'nonsense';
-     *   }
-     * };
-     *
-     * _.result(object, 'cheese');
-     * // => 'crumpets'
-     *
-     * _.result(object, 'stuff');
-     * // => 'nonsense'
-     */
-    function result(object, key) {
-      if (object) {
-        var value = object[key];
-        return isFunction(value) ? object[key]() : value;
-      }
-    }
-
-    /**
-     * A micro-templating method that handles arbitrary delimiters, preserves
-     * whitespace, and correctly escapes quotes within interpolated code.
-     *
-     * Note: In the development build, `_.template` utilizes sourceURLs for easier
-     * debugging. See http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl
-     *
-     * For more information on precompiling templates see:
-     * https://lodash.com/custom-builds
-     *
-     * For more information on Chrome extension sandboxes see:
-     * http://developer.chrome.com/stable/extensions/sandboxingEval.html
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {string} text The template text.
-     * @param {Object} data The data object used to populate the text.
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Converts `string` to [camel case](https://en.wikipedia.org/wiki/CamelCase).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the camel cased string.
+     * @example
+     *
+     * _.camelCase('Foo Bar');
+     * // => 'fooBar'
+     *
+     * _.camelCase('--foo-bar');
+     * // => 'fooBar'
+     *
+     * _.camelCase('__foo_bar__');
+     * // => 'fooBar'
+     */
+    var camelCase = createCompounder(function(result, word, index) {
+      word = word.toLowerCase();
+      return result + (index ? (word.charAt(0).toUpperCase() + word.slice(1)) : word);
+    });
+
+    /**
+     * Capitalizes the first character of `string`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to capitalize.
+     * @returns {string} Returns the capitalized string.
+     * @example
+     *
+     * _.capitalize('fred');
+     * // => 'Fred'
+     */
+    function capitalize(string) {
+      string = baseToString(string);
+      return string && (string.charAt(0).toUpperCase() + string.slice(1));
+    }
+
+    /**
+     * Deburrs `string` by converting [latin-1 supplementary letters](https://en.wikipedia.org/wiki/Latin-1_Supplement_(Unicode_block)#Character_table)
+     * to basic latin letters and removing [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to deburr.
+     * @returns {string} Returns the deburred string.
+     * @example
+     *
+     * _.deburr('déjà vu');
+     * // => 'deja vu'
+     */
+    function deburr(string) {
+      string = baseToString(string);
+      return string && string.replace(reLatin1, deburrLetter).replace(reComboMark, '');
+    }
+
+    /**
+     * Checks if `string` ends with the given target string.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to search.
+     * @param {string} [target] The string to search for.
+     * @param {number} [position=string.length] The position to search from.
+     * @returns {boolean} Returns `true` if `string` ends with `target`, else `false`.
+     * @example
+     *
+     * _.endsWith('abc', 'c');
+     * // => true
+     *
+     * _.endsWith('abc', 'b');
+     * // => false
+     *
+     * _.endsWith('abc', 'b', 2);
+     * // => true
+     */
+    function endsWith(string, target, position) {
+      string = baseToString(string);
+      target = (target + '');
+
+      var length = string.length;
+      position = position === undefined
+        ? length
+        : nativeMin(position < 0 ? 0 : (+position || 0), length);
+
+      position -= target.length;
+      return position >= 0 && string.indexOf(target, position) == position;
+    }
+
+    /**
+     * Converts the characters "&", "<", ">", '"', "'", and "\`", in `string` to
+     * their corresponding HTML entities.
+     *
+     * **Note:** No other characters are escaped. To escape additional characters
+     * use a third-party library like [_he_](https://mths.be/he).
+     *
+     * Though the ">" character is escaped for symmetry, characters like
+     * ">" and "/" don't need escaping in HTML and have no special meaning
+     * unless they're part of a tag or unquoted attribute value.
+     * See [Mathias Bynens's article](https://mathiasbynens.be/notes/ambiguous-ampersands)
+     * (under "semi-related fun fact") for more details.
+     *
+     * Backticks are escaped because in Internet Explorer < 9, they can break out
+     * of attribute values or HTML comments. See [#59](https://html5sec.org/#59),
+     * [#102](https://html5sec.org/#102), [#108](https://html5sec.org/#108), and
+     * [#133](https://html5sec.org/#133) of the [HTML5 Security Cheatsheet](https://html5sec.org/)
+     * for more details.
+     *
+     * When working with HTML you should always [quote attribute values](http://wonko.com/post/html-escaping)
+     * to reduce XSS vectors.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to escape.
+     * @returns {string} Returns the escaped string.
+     * @example
+     *
+     * _.escape('fred, barney, & pebbles');
+     * // => 'fred, barney, &amp; pebbles'
+     */
+    function escape(string) {
+      // Reset `lastIndex` because in IE < 9 `String#replace` does not.
+      string = baseToString(string);
+      return (string && reHasUnescapedHtml.test(string))
+        ? string.replace(reUnescapedHtml, escapeHtmlChar)
+        : string;
+    }
+
+    /**
+     * Escapes the `RegExp` special characters "\", "/", "^", "$", ".", "|", "?",
+     * "*", "+", "(", ")", "[", "]", "{" and "}" in `string`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to escape.
+     * @returns {string} Returns the escaped string.
+     * @example
+     *
+     * _.escapeRegExp('[lodash](https://lodash.com/)');
+     * // => '\[lodash\]\(https:\/\/lodash\.com\/\)'
+     */
+    function escapeRegExp(string) {
+      string = baseToString(string);
+      return (string && reHasRegExpChars.test(string))
+        ? string.replace(reRegExpChars, escapeRegExpChar)
+        : (string || '(?:)');
+    }
+
+    /**
+     * Converts `string` to [kebab case](https://en.wikipedia.org/wiki/Letter_case#Special_case_styles).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the kebab cased string.
+     * @example
+     *
+     * _.kebabCase('Foo Bar');
+     * // => 'foo-bar'
+     *
+     * _.kebabCase('fooBar');
+     * // => 'foo-bar'
+     *
+     * _.kebabCase('__foo_bar__');
+     * // => 'foo-bar'
+     */
+    var kebabCase = createCompounder(function(result, word, index) {
+      return result + (index ? '-' : '') + word.toLowerCase();
+    });
+
+    /**
+     * Pads `string` on the left and right sides if it's shorter than `length`.
+     * Padding characters are truncated if they can't be evenly divided by `length`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to pad.
+     * @param {number} [length=0] The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the padded string.
+     * @example
+     *
+     * _.pad('abc', 8);
+     * // => '  abc   '
+     *
+     * _.pad('abc', 8, '_-');
+     * // => '_-abc_-_'
+     *
+     * _.pad('abc', 3);
+     * // => 'abc'
+     */
+    function pad(string, length, chars) {
+      string = baseToString(string);
+      length = +length;
+
+      var strLength = string.length;
+      if (strLength >= length || !nativeIsFinite(length)) {
+        return string;
+      }
+      var mid = (length - strLength) / 2,
+          leftLength = nativeFloor(mid),
+          rightLength = nativeCeil(mid);
+
+      chars = createPadding('', rightLength, chars);
+      return chars.slice(0, leftLength) + string + chars;
+    }
+
+    /**
+     * Pads `string` on the left side if it's shorter than `length`. Padding
+     * characters are truncated if they exceed `length`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to pad.
+     * @param {number} [length=0] The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the padded string.
+     * @example
+     *
+     * _.padLeft('abc', 6);
+     * // => '   abc'
+     *
+     * _.padLeft('abc', 6, '_-');
+     * // => '_-_abc'
+     *
+     * _.padLeft('abc', 3);
+     * // => 'abc'
+     */
+    var padLeft = createPadDir();
+
+    /**
+     * Pads `string` on the right side if it's shorter than `length`. Padding
+     * characters are truncated if they exceed `length`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to pad.
+     * @param {number} [length=0] The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the padded string.
+     * @example
+     *
+     * _.padRight('abc', 6);
+     * // => 'abc   '
+     *
+     * _.padRight('abc', 6, '_-');
+     * // => 'abc_-_'
+     *
+     * _.padRight('abc', 3);
+     * // => 'abc'
+     */
+    var padRight = createPadDir(true);
+
+    /**
+     * Converts `string` to an integer of the specified radix. If `radix` is
+     * `undefined` or `0`, a `radix` of `10` is used unless `value` is a hexadecimal,
+     * in which case a `radix` of `16` is used.
+     *
+     * **Note:** This method aligns with the [ES5 implementation](https://es5.github.io/#E)
+     * of `parseInt`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} string The string to convert.
+     * @param {number} [radix] The radix to interpret `value` by.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {number} Returns the converted integer.
+     * @example
+     *
+     * _.parseInt('08');
+     * // => 8
+     *
+     * _.map(['6', '08', '10'], _.parseInt);
+     * // => [6, 8, 10]
+     */
+    function parseInt(string, radix, guard) {
+      // Firefox < 21 and Opera < 15 follow ES3 for `parseInt`.
+      // Chrome fails to trim leading <BOM> whitespace characters.
+      // See https://code.google.com/p/v8/issues/detail?id=3109 for more details.
+      if (guard ? isIterateeCall(string, radix, guard) : radix == null) {
+        radix = 0;
+      } else if (radix) {
+        radix = +radix;
+      }
+      string = trim(string);
+      return nativeParseInt(string, radix || (reHasHexPrefix.test(string) ? 16 : 10));
+    }
+
+    /**
+     * Repeats the given string `n` times.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to repeat.
+     * @param {number} [n=0] The number of times to repeat the string.
+     * @returns {string} Returns the repeated string.
+     * @example
+     *
+     * _.repeat('*', 3);
+     * // => '***'
+     *
+     * _.repeat('abc', 2);
+     * // => 'abcabc'
+     *
+     * _.repeat('abc', 0);
+     * // => ''
+     */
+    function repeat(string, n) {
+      var result = '';
+      string = baseToString(string);
+      n = +n;
+      if (n < 1 || !string || !nativeIsFinite(n)) {
+        return result;
+      }
+      // Leverage the exponentiation by squaring algorithm for a faster repeat.
+      // See https://en.wikipedia.org/wiki/Exponentiation_by_squaring for more details.
+      do {
+        if (n % 2) {
+          result += string;
+        }
+        n = nativeFloor(n / 2);
+        string += string;
+      } while (n);
+
+      return result;
+    }
+
+    /**
+     * Converts `string` to [snake case](https://en.wikipedia.org/wiki/Snake_case).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the snake cased string.
+     * @example
+     *
+     * _.snakeCase('Foo Bar');
+     * // => 'foo_bar'
+     *
+     * _.snakeCase('fooBar');
+     * // => 'foo_bar'
+     *
+     * _.snakeCase('--foo-bar');
+     * // => 'foo_bar'
+     */
+    var snakeCase = createCompounder(function(result, word, index) {
+      return result + (index ? '_' : '') + word.toLowerCase();
+    });
+
+    /**
+     * Converts `string` to [start case](https://en.wikipedia.org/wiki/Letter_case#Stylistic_or_specialised_usage).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the start cased string.
+     * @example
+     *
+     * _.startCase('--foo-bar');
+     * // => 'Foo Bar'
+     *
+     * _.startCase('fooBar');
+     * // => 'Foo Bar'
+     *
+     * _.startCase('__foo_bar__');
+     * // => 'Foo Bar'
+     */
+    var startCase = createCompounder(function(result, word, index) {
+      return result + (index ? ' ' : '') + (word.charAt(0).toUpperCase() + word.slice(1));
+    });
+
+    /**
+     * Checks if `string` starts with the given target string.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to search.
+     * @param {string} [target] The string to search for.
+     * @param {number} [position=0] The position to search from.
+     * @returns {boolean} Returns `true` if `string` starts with `target`, else `false`.
+     * @example
+     *
+     * _.startsWith('abc', 'a');
+     * // => true
+     *
+     * _.startsWith('abc', 'b');
+     * // => false
+     *
+     * _.startsWith('abc', 'b', 1);
+     * // => true
+     */
+    function startsWith(string, target, position) {
+      string = baseToString(string);
+      position = position == null
+        ? 0
+        : nativeMin(position < 0 ? 0 : (+position || 0), string.length);
+
+      return string.lastIndexOf(target, position) == position;
+    }
+
+    /**
+     * Creates a compiled template function that can interpolate data properties
+     * in "interpolate" delimiters, HTML-escape interpolated data properties in
+     * "escape" delimiters, and execute JavaScript in "evaluate" delimiters. Data
+     * properties may be accessed as free variables in the template. If a setting
+     * object is provided it takes precedence over `_.templateSettings` values.
+     *
+     * **Note:** In the development build `_.template` utilizes
+     * [sourceURLs](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl)
+     * for easier debugging.
+     *
+     * For more information on precompiling templates see
+     * [lodash's custom builds documentation](https://lodash.com/custom-builds).
+     *
+     * For more information on Chrome extension sandboxes see
+     * [Chrome's extensions documentation](https://developer.chrome.com/extensions/sandboxingEval).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The template string.
      * @param {Object} [options] The options object.
-     * @param {RegExp} [options.escape] The "escape" delimiter.
+     * @param {RegExp} [options.escape] The HTML "escape" delimiter.
      * @param {RegExp} [options.evaluate] The "evaluate" delimiter.
-     * @param {Object} [options.imports] An object to import into the template as local variables.
+     * @param {Object} [options.imports] An object to import into the template as free variables.
      * @param {RegExp} [options.interpolate] The "interpolate" delimiter.
-     * @param {string} [sourceURL] The sourceURL of the template's compiled source.
-     * @param {string} [variable] The data object variable name.
-     * @returns {Function|string} Returns a compiled function when no `data` object
-     *  is given, else it returns the interpolated text.
+     * @param {string} [options.sourceURL] The sourceURL of the template's compiled source.
+     * @param {string} [options.variable] The data object variable name.
+     * @param- {Object} [otherOptions] Enables the legacy `options` param signature.
+     * @returns {Function} Returns the compiled template function.
      * @example
      *
      * // using the "interpolate" delimiter to create a compiled template
-     * var compiled = _.template('hello <%= name %>');
-     * compiled({ 'name': 'fred' });
-     * // => 'hello fred'
-     *
-     * // using the "escape" delimiter to escape HTML in data property values
-     * _.template('<b><%- value %></b>', { 'value': '<script>' });
+     * var compiled = _.template('hello <%= user %>!');
+     * compiled({ 'user': 'fred' });
+     * // => 'hello fred!'
+     *
+     * // using the HTML "escape" delimiter to escape data property values
+     * var compiled = _.template('<b><%- value %></b>');
+     * compiled({ 'value': '<script>' });
      * // => '<b>&lt;script&gt;</b>'
      *
-     * // using the "evaluate" delimiter to generate HTML
-     * var list = '<% _.forEach(people, function(name) { %><li><%- name %></li><% }); %>';
-     * _.template(list, { 'people': ['fred', 'barney'] });
+     * // using the "evaluate" delimiter to execute JavaScript and generate HTML
+     * var compiled = _.template('<% _.forEach(users, function(user) { %><li><%- user %></li><% }); %>');
+     * compiled({ 'users': ['fred', 'barney'] });
      * // => '<li>fred</li><li>barney</li>'
      *
-     * // using the ES6 delimiter as an alternative to the default "interpolate" delimiter
-     * _.template('hello ${ name }', { 'name': 'pebbles' });
-     * // => 'hello pebbles'
-     *
      * // using the internal `print` function in "evaluate" delimiters
-     * _.template('<% print("hello " + name); %>!', { 'name': 'barney' });
+     * var compiled = _.template('<% print("hello " + user); %>!');
+     * compiled({ 'user': 'barney' });
      * // => 'hello barney!'
      *
-     * // using a custom template delimiters
-     * _.templateSettings = {
-     *   'interpolate': /{{([\s\S]+?)}}/g
-     * };
-     *
-     * _.template('hello {{ name }}!', { 'name': 'mustache' });
+     * // using the ES delimiter as an alternative to the default "interpolate" delimiter
+     * var compiled = _.template('hello ${ user }!');
+     * compiled({ 'user': 'pebbles' });
+     * // => 'hello pebbles!'
+     *
+     * // using custom template delimiters
+     * _.templateSettings.interpolate = /{{([\s\S]+?)}}/g;
+     * var compiled = _.template('hello {{ user }}!');
+     * compiled({ 'user': 'mustache' });
      * // => 'hello mustache!'
      *
-     * // using the `imports` option to import jQuery
-     * var list = '<% jq.each(people, function(name) { %><li><%- name %></li><% }); %>';
-     * _.template(list, { 'people': ['fred', 'barney'] }, { 'imports': { 'jq': jQuery } });
+     * // using backslashes to treat delimiters as plain text
+     * var compiled = _.template('<%= "\\<%- value %\\>" %>');
+     * compiled({ 'value': 'ignored' });
+     * // => '<%- value %>'
+     *
+     * // using the `imports` option to import `jQuery` as `jq`
+     * var text = '<% jq.each(users, function(user) { %><li><%- user %></li><% }); %>';
+     * var compiled = _.template(text, { 'imports': { 'jq': jQuery } });
+     * compiled({ 'users': ['fred', 'barney'] });
      * // => '<li>fred</li><li>barney</li>'
      *
      * // using the `sourceURL` option to specify a custom sourceURL for the template
-     * var compiled = _.template('hello <%= name %>', null, { 'sourceURL': '/basic/greeting.jst' });
+     * var compiled = _.template('hello <%= user %>!', { 'sourceURL': '/basic/greeting.jst' });
      * compiled(data);
      * // => find the source of "greeting.jst" under the Sources tab or Resources panel of the web inspector
      *
      * // using the `variable` option to ensure a with-statement isn't used in the compiled template
-     * var compiled = _.template('hi <%= data.name %>!', null, { 'variable': 'data' });
+     * var compiled = _.template('hi <%= data.user %>!', { 'variable': 'data' });
      * compiled.source;
      * // => function(data) {
-     *   var __t, __p = '', __e = _.escape;
-     *   __p += 'hi ' + ((__t = ( data.name )) == null ? '' : __t) + '!';
-     *   return __p;
-     * }
+     * //   var __t, __p = '';
+     * //   __p += 'hi ' + ((__t = ( data.user )) == null ? '' : __t) + '!';
+     * //   return __p;
+     * // }
      *
      * // using the `source` property to inline compiled templates for meaningful
      * // line numbers in error messages and a stack trace
@@ -6218,27 +10713,28 @@
      *   };\
      * ');
      */
-    function template(text, data, options) {
-      // based on John Resig's `tmpl` implementation
-      // http://ejohn.org/blog/javascript-micro-templating/
-      // and Laura Doktorova's doT.js
-      // https://github.com/olado/doT
+    function template(string, options, otherOptions) {
+      // Based on John Resig's `tmpl` implementation (http://ejohn.org/blog/javascript-micro-templating/)
+      // and Laura Doktorova's doT.js (https://github.com/olado/doT).
       var settings = lodash.templateSettings;
-      text = String(text || '');
-
-      // avoid missing dependencies when `iteratorTemplate` is not defined
-      options = defaults({}, options, settings);
-
-      var imports = defaults({}, options.imports, settings.imports),
+
+      if (otherOptions && isIterateeCall(string, options, otherOptions)) {
+        options = otherOptions = undefined;
+      }
+      string = baseToString(string);
+      options = assignWith(baseAssign({}, otherOptions || options), settings, assignOwnDefaults);
+
+      var imports = assignWith(baseAssign({}, options.imports), settings.imports, assignOwnDefaults),
           importsKeys = keys(imports),
-          importsValues = values(imports);
-
-      var isEvaluating,
+          importsValues = baseValues(imports, importsKeys);
+
+      var isEscaping,
+          isEvaluating,
           index = 0,
           interpolate = options.interpolate || reNoMatch,
           source = "__p += '";
 
-      // compile the regexp to match each delimiter
+      // Compile the regexp to match each delimiter.
       var reDelimiters = RegExp(
         (options.escape || reNoMatch).source + '|' +
         interpolate.source + '|' +
@@ -6246,14 +10742,22 @@
         (options.evaluate || reNoMatch).source + '|$'
       , 'g');
 
-      text.replace(reDelimiters, function(match, escapeValue, interpolateValue, esTemplateValue, evaluateValue, offset) {
+      // Use a sourceURL for easier debugging.
+      var sourceURL = '//# sourceURL=' +
+        ('sourceURL' in options
+          ? options.sourceURL
+          : ('lodash.templateSources[' + (++templateCounter) + ']')
+        ) + '\n';
+
+      string.replace(reDelimiters, function(match, escapeValue, interpolateValue, esTemplateValue, evaluateValue, offset) {
         interpolateValue || (interpolateValue = esTemplateValue);
 
-        // escape characters that cannot be included in string literals
-        source += text.slice(index, offset).replace(reUnescapedString, escapeStringChar);
-
-        // replace delimiters with snippets
+        // Escape characters that can't be included in string literals.
+        source += string.slice(index, offset).replace(reUnescapedString, escapeStringChar);
+
+        // Replace delimiters with snippets.
         if (escapeValue) {
+          isEscaping = true;
           source += "' +\n__e(" + escapeValue + ") +\n'";
         }
         if (evaluateValue) {
@@ -6265,31 +10769,35 @@
         }
         index = offset + match.length;
 
-        // the JS engine embedded in Adobe products requires returning the `match`
-        // string in order to produce the correct `offset` value
+        // The JS engine embedded in Adobe products requires returning the `match`
+        // string in order to produce the correct `offset` value.
         return match;
       });
 
       source += "';\n";
 
-      // if `variable` is not specified, wrap a with-statement around the generated
-      // code to add the data object to the top of the scope chain
-      var variable = options.variable,
-          hasVariable = variable;
-
-      if (!hasVariable) {
-        variable = 'obj';
-        source = 'with (' + variable + ') {\n' + source + '\n}\n';
-      }
-      // cleanup code by stripping empty strings
+      // If `variable` is not specified wrap a with-statement around the generated
+      // code to add the data object to the top of the scope chain.
+      var variable = options.variable;
+      if (!variable) {
+        source = 'with (obj) {\n' + source + '\n}\n';
+      }
+      // Cleanup code by stripping empty strings.
       source = (isEvaluating ? source.replace(reEmptyStringLeading, '') : source)
         .replace(reEmptyStringMiddle, '$1')
         .replace(reEmptyStringTrailing, '$1;');
 
-      // frame code as the function body
-      source = 'function(' + variable + ') {\n' +
-        (hasVariable ? '' : variable + ' || (' + variable + ' = {});\n') +
-        "var __t, __p = '', __e = _.escape" +
+      // Frame code as the function body.
+      source = 'function(' + (variable || 'obj') + ') {\n' +
+        (variable
+          ? ''
+          : 'obj || (obj = {});\n'
+        ) +
+        "var __t, __p = ''" +
+        (isEscaping
+           ? ', __e = _.escape'
+           : ''
+        ) +
         (isEvaluating
           ? ', __j = Array.prototype.join;\n' +
             "function print() { __p += __j.call(arguments, '') }\n"
@@ -6298,86 +10806,776 @@
         source +
         'return __p\n}';
 
-      // Use a sourceURL for easier debugging.
-      // http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl
-      var sourceURL = '\n/*\n//# sourceURL=' + (options.sourceURL || '/lodash/template/source[' + (templateCounter++) + ']') + '\n*/';
-
-      try {
-        var result = Function(importsKeys, 'return ' + source + sourceURL).apply(undefined, importsValues);
-      } catch(e) {
-        e.source = source;
-        throw e;
-      }
-      if (data) {
-        return result(data);
-      }
-      // provide the compiled function's source by its `toString` method, in
-      // supported environments, or the `source` property as a convenience for
-      // inlining compiled templates during the build process
+      var result = attempt(function() {
+        return Function(importsKeys, sourceURL + 'return ' + source).apply(undefined, importsValues);
+      });
+
+      // Provide the compiled function's source by its `toString` method or
+      // the `source` property as a convenience for inlining compiled templates.
       result.source = source;
-      return result;
-    }
-
-    /**
-     * Executes the callback `n` times, returning an array of the results
-     * of each callback execution. The callback is bound to `thisArg` and invoked
-     * with one argument; (index).
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {number} n The number of times to execute the callback.
-     * @param {Function} callback The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns an array of the results of each `callback` execution.
-     * @example
-     *
-     * var diceRolls = _.times(3, _.partial(_.random, 1, 6));
-     * // => [3, 6, 4]
-     *
-     * _.times(3, function(n) { mage.castSpell(n); });
-     * // => calls `mage.castSpell(n)` three times, passing `n` of `0`, `1`, and `2` respectively
-     *
-     * _.times(3, function(n) { this.cast(n); }, mage);
-     * // => also calls `mage.castSpell(n)` three times
-     */
-    function times(n, callback, thisArg) {
-      n = (n = +n) > -1 ? n : 0;
-      var index = -1,
-          result = Array(n);
-
-      callback = baseCreateCallback(callback, thisArg, 1);
-      while (++index < n) {
-        result[index] = callback(index);
+      if (isError(result)) {
+        throw result;
       }
       return result;
     }
 
     /**
-     * The inverse of `_.escape` this method converts the HTML entities
-     * `&amp;`, `&lt;`, `&gt;`, `&quot;`, and `&#39;` in `string` to their
+     * Removes leading and trailing whitespace or specified characters from `string`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to trim.
+     * @param {string} [chars=whitespace] The characters to trim.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {string} Returns the trimmed string.
+     * @example
+     *
+     * _.trim('  abc  ');
+     * // => 'abc'
+     *
+     * _.trim('-_-abc-_-', '_-');
+     * // => 'abc'
+     *
+     * _.map(['  foo  ', '  bar  '], _.trim);
+     * // => ['foo', 'bar']
+     */
+    function trim(string, chars, guard) {
+      var value = string;
+      string = baseToString(string);
+      if (!string) {
+        return string;
+      }
+      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
+        return string.slice(trimmedLeftIndex(string), trimmedRightIndex(string) + 1);
+      }
+      chars = (chars + '');
+      return string.slice(charsLeftIndex(string, chars), charsRightIndex(string, chars) + 1);
+    }
+
+    /**
+     * Removes leading whitespace or specified characters from `string`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to trim.
+     * @param {string} [chars=whitespace] The characters to trim.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {string} Returns the trimmed string.
+     * @example
+     *
+     * _.trimLeft('  abc  ');
+     * // => 'abc  '
+     *
+     * _.trimLeft('-_-abc-_-', '_-');
+     * // => 'abc-_-'
+     */
+    function trimLeft(string, chars, guard) {
+      var value = string;
+      string = baseToString(string);
+      if (!string) {
+        return string;
+      }
+      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
+        return string.slice(trimmedLeftIndex(string));
+      }
+      return string.slice(charsLeftIndex(string, (chars + '')));
+    }
+
+    /**
+     * Removes trailing whitespace or specified characters from `string`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to trim.
+     * @param {string} [chars=whitespace] The characters to trim.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {string} Returns the trimmed string.
+     * @example
+     *
+     * _.trimRight('  abc  ');
+     * // => '  abc'
+     *
+     * _.trimRight('-_-abc-_-', '_-');
+     * // => '-_-abc'
+     */
+    function trimRight(string, chars, guard) {
+      var value = string;
+      string = baseToString(string);
+      if (!string) {
+        return string;
+      }
+      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
+        return string.slice(0, trimmedRightIndex(string) + 1);
+      }
+      return string.slice(0, charsRightIndex(string, (chars + '')) + 1);
+    }
+
+    /**
+     * Truncates `string` if it's longer than the given maximum string length.
+     * The last characters of the truncated string are replaced with the omission
+     * string which defaults to "...".
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to truncate.
+     * @param {Object|number} [options] The options object or maximum string length.
+     * @param {number} [options.length=30] The maximum string length.
+     * @param {string} [options.omission='...'] The string to indicate text is omitted.
+     * @param {RegExp|string} [options.separator] The separator pattern to truncate to.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {string} Returns the truncated string.
+     * @example
+     *
+     * _.trunc('hi-diddly-ho there, neighborino');
+     * // => 'hi-diddly-ho there, neighbo...'
+     *
+     * _.trunc('hi-diddly-ho there, neighborino', 24);
+     * // => 'hi-diddly-ho there, n...'
+     *
+     * _.trunc('hi-diddly-ho there, neighborino', {
+     *   'length': 24,
+     *   'separator': ' '
+     * });
+     * // => 'hi-diddly-ho there,...'
+     *
+     * _.trunc('hi-diddly-ho there, neighborino', {
+     *   'length': 24,
+     *   'separator': /,? +/
+     * });
+     * // => 'hi-diddly-ho there...'
+     *
+     * _.trunc('hi-diddly-ho there, neighborino', {
+     *   'omission': ' [...]'
+     * });
+     * // => 'hi-diddly-ho there, neig [...]'
+     */
+    function trunc(string, options, guard) {
+      if (guard && isIterateeCall(string, options, guard)) {
+        options = undefined;
+      }
+      var length = DEFAULT_TRUNC_LENGTH,
+          omission = DEFAULT_TRUNC_OMISSION;
+
+      if (options != null) {
+        if (isObject(options)) {
+          var separator = 'separator' in options ? options.separator : separator;
+          length = 'length' in options ? (+options.length || 0) : length;
+          omission = 'omission' in options ? baseToString(options.omission) : omission;
+        } else {
+          length = +options || 0;
+        }
+      }
+      string = baseToString(string);
+      if (length >= string.length) {
+        return string;
+      }
+      var end = length - omission.length;
+      if (end < 1) {
+        return omission;
+      }
+      var result = string.slice(0, end);
+      if (separator == null) {
+        return result + omission;
+      }
+      if (isRegExp(separator)) {
+        if (string.slice(end).search(separator)) {
+          var match,
+              newEnd,
+              substring = string.slice(0, end);
+
+          if (!separator.global) {
+            separator = RegExp(separator.source, (reFlags.exec(separator) || '') + 'g');
+          }
+          separator.lastIndex = 0;
+          while ((match = separator.exec(substring))) {
+            newEnd = match.index;
+          }
+          result = result.slice(0, newEnd == null ? end : newEnd);
+        }
+      } else if (string.indexOf(separator, end) != end) {
+        var index = result.lastIndexOf(separator);
+        if (index > -1) {
+          result = result.slice(0, index);
+        }
+      }
+      return result + omission;
+    }
+
+    /**
+     * The inverse of `_.escape`; this method converts the HTML entities
+     * `&amp;`, `&lt;`, `&gt;`, `&quot;`, `&#39;`, and `&#96;` in `string` to their
      * corresponding characters.
      *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {string} string The string to unescape.
+     * **Note:** No other HTML entities are unescaped. To unescape additional HTML
+     * entities use a third-party library like [_he_](https://mths.be/he).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to unescape.
      * @returns {string} Returns the unescaped string.
      * @example
      *
-     * _.unescape('Fred, Barney &amp; Pebbles');
-     * // => 'Fred, Barney & Pebbles'
+     * _.unescape('fred, barney, &amp; pebbles');
+     * // => 'fred, barney, & pebbles'
      */
     function unescape(string) {
-      return string == null ? '' : String(string).replace(reEscapedHtml, unescapeHtmlChar);
-    }
-
-    /**
-     * Generates a unique ID. If `prefix` is provided the ID will be appended to it.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
+      string = baseToString(string);
+      return (string && reHasEscapedHtml.test(string))
+        ? string.replace(reEscapedHtml, unescapeHtmlChar)
+        : string;
+    }
+
+    /**
+     * Splits `string` into an array of its words.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to inspect.
+     * @param {RegExp|string} [pattern] The pattern to match words.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the words of `string`.
+     * @example
+     *
+     * _.words('fred, barney, & pebbles');
+     * // => ['fred', 'barney', 'pebbles']
+     *
+     * _.words('fred, barney, & pebbles', /[^, ]+/g);
+     * // => ['fred', 'barney', '&', 'pebbles']
+     */
+    function words(string, pattern, guard) {
+      if (guard && isIterateeCall(string, pattern, guard)) {
+        pattern = undefined;
+      }
+      string = baseToString(string);
+      return string.match(pattern || reWords) || [];
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Attempts to invoke `func`, returning either the result or the caught error
+     * object. Any additional arguments are provided to `func` when it's invoked.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Function} func The function to attempt.
+     * @returns {*} Returns the `func` result or error object.
+     * @example
+     *
+     * // avoid throwing errors for invalid selectors
+     * var elements = _.attempt(function(selector) {
+     *   return document.querySelectorAll(selector);
+     * }, '>_>');
+     *
+     * if (_.isError(elements)) {
+     *   elements = [];
+     * }
+     */
+    var attempt = restParam(function(func, args) {
+      try {
+        return func.apply(undefined, args);
+      } catch(e) {
+        return isError(e) ? e : new Error(e);
+      }
+    });
+
+    /**
+     * Creates a function that invokes `func` with the `this` binding of `thisArg`
+     * and arguments of the created function. If `func` is a property name the
+     * created callback returns the property value for a given element. If `func`
+     * is an object the created callback returns `true` for elements that contain
+     * the equivalent object properties, otherwise it returns `false`.
+     *
+     * @static
+     * @memberOf _
+     * @alias iteratee
+     * @category Utility
+     * @param {*} [func=_.identity] The value to convert to a callback.
+     * @param {*} [thisArg] The `this` binding of `func`.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Function} Returns the callback.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 40 }
+     * ];
+     *
+     * // wrap to create custom callback shorthands
+     * _.callback = _.wrap(_.callback, function(callback, func, thisArg) {
+     *   var match = /^(.+?)__([gl]t)(.+)$/.exec(func);
+     *   if (!match) {
+     *     return callback(func, thisArg);
+     *   }
+     *   return function(object) {
+     *     return match[2] == 'gt'
+     *       ? object[match[1]] > match[3]
+     *       : object[match[1]] < match[3];
+     *   };
+     * });
+     *
+     * _.filter(users, 'age__gt36');
+     * // => [{ 'user': 'fred', 'age': 40 }]
+     */
+    function callback(func, thisArg, guard) {
+      if (guard && isIterateeCall(func, thisArg, guard)) {
+        thisArg = undefined;
+      }
+      return isObjectLike(func)
+        ? matches(func)
+        : baseCallback(func, thisArg);
+    }
+
+    /**
+     * Creates a function that returns `value`.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {*} value The value to return from the new function.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var object = { 'user': 'fred' };
+     * var getter = _.constant(object);
+     *
+     * getter() === object;
+     * // => true
+     */
+    function constant(value) {
+      return function() {
+        return value;
+      };
+    }
+
+    /**
+     * This method returns the first argument provided to it.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {*} value Any value.
+     * @returns {*} Returns `value`.
+     * @example
+     *
+     * var object = { 'user': 'fred' };
+     *
+     * _.identity(object) === object;
+     * // => true
+     */
+    function identity(value) {
+      return value;
+    }
+
+    /**
+     * Creates a function that performs a deep comparison between a given object
+     * and `source`, returning `true` if the given object has equivalent property
+     * values, else `false`.
+     *
+     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
+     * numbers, `Object` objects, regexes, and strings. Objects are compared by
+     * their own, not inherited, enumerable properties. For comparing a single
+     * own or inherited property value see `_.matchesProperty`.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Object} source The object of property values to match.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': true },
+     *   { 'user': 'fred',   'age': 40, 'active': false }
+     * ];
+     *
+     * _.filter(users, _.matches({ 'age': 40, 'active': false }));
+     * // => [{ 'user': 'fred', 'age': 40, 'active': false }]
+     */
+    function matches(source) {
+      return baseMatches(baseClone(source, true));
+    }
+
+    /**
+     * Creates a function that compares the property value of `path` on a given
+     * object to `value`.
+     *
+     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
+     * numbers, `Object` objects, regexes, and strings. Objects are compared by
+     * their own, not inherited, enumerable properties.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Array|string} path The path of the property to get.
+     * @param {*} srcValue The value to match.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney' },
+     *   { 'user': 'fred' }
+     * ];
+     *
+     * _.find(users, _.matchesProperty('user', 'fred'));
+     * // => { 'user': 'fred' }
+     */
+    function matchesProperty(path, srcValue) {
+      return baseMatchesProperty(path, baseClone(srcValue, true));
+    }
+
+    /**
+     * Creates a function that invokes the method at `path` on a given object.
+     * Any additional arguments are provided to the invoked method.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Array|string} path The path of the method to invoke.
+     * @param {...*} [args] The arguments to invoke the method with.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var objects = [
+     *   { 'a': { 'b': { 'c': _.constant(2) } } },
+     *   { 'a': { 'b': { 'c': _.constant(1) } } }
+     * ];
+     *
+     * _.map(objects, _.method('a.b.c'));
+     * // => [2, 1]
+     *
+     * _.invoke(_.sortBy(objects, _.method(['a', 'b', 'c'])), 'a.b.c');
+     * // => [1, 2]
+     */
+    var method = restParam(function(path, args) {
+      return function(object) {
+        return invokePath(object, path, args);
+      };
+    });
+
+    /**
+     * The opposite of `_.method`; this method creates a function that invokes
+     * the method at a given path on `object`. Any additional arguments are
+     * provided to the invoked method.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Object} object The object to query.
+     * @param {...*} [args] The arguments to invoke the method with.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var array = _.times(3, _.constant),
+     *     object = { 'a': array, 'b': array, 'c': array };
+     *
+     * _.map(['a[2]', 'c[0]'], _.methodOf(object));
+     * // => [2, 0]
+     *
+     * _.map([['a', '2'], ['c', '0']], _.methodOf(object));
+     * // => [2, 0]
+     */
+    var methodOf = restParam(function(object, args) {
+      return function(path) {
+        return invokePath(object, path, args);
+      };
+    });
+
+    /**
+     * Adds all own enumerable function properties of a source object to the
+     * destination object. If `object` is a function then methods are added to
+     * its prototype as well.
+     *
+     * **Note:** Use `_.runInContext` to create a pristine `lodash` function to
+     * avoid conflicts caused by modifying the original.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Function|Object} [object=lodash] The destination object.
+     * @param {Object} source The object of functions to add.
+     * @param {Object} [options] The options object.
+     * @param {boolean} [options.chain=true] Specify whether the functions added
+     *  are chainable.
+     * @returns {Function|Object} Returns `object`.
+     * @example
+     *
+     * function vowels(string) {
+     *   return _.filter(string, function(v) {
+     *     return /[aeiou]/i.test(v);
+     *   });
+     * }
+     *
+     * _.mixin({ 'vowels': vowels });
+     * _.vowels('fred');
+     * // => ['e']
+     *
+     * _('fred').vowels().value();
+     * // => ['e']
+     *
+     * _.mixin({ 'vowels': vowels }, { 'chain': false });
+     * _('fred').vowels();
+     * // => ['e']
+     */
+    function mixin(object, source, options) {
+      if (options == null) {
+        var isObj = isObject(source),
+            props = isObj ? keys(source) : undefined,
+            methodNames = (props && props.length) ? baseFunctions(source, props) : undefined;
+
+        if (!(methodNames ? methodNames.length : isObj)) {
+          methodNames = false;
+          options = source;
+          source = object;
+          object = this;
+        }
+      }
+      if (!methodNames) {
+        methodNames = baseFunctions(source, keys(source));
+      }
+      var chain = true,
+          index = -1,
+          isFunc = isFunction(object),
+          length = methodNames.length;
+
+      if (options === false) {
+        chain = false;
+      } else if (isObject(options) && 'chain' in options) {
+        chain = options.chain;
+      }
+      while (++index < length) {
+        var methodName = methodNames[index],
+            func = source[methodName];
+
+        object[methodName] = func;
+        if (isFunc) {
+          object.prototype[methodName] = (function(func) {
+            return function() {
+              var chainAll = this.__chain__;
+              if (chain || chainAll) {
+                var result = object(this.__wrapped__),
+                    actions = result.__actions__ = arrayCopy(this.__actions__);
+
+                actions.push({ 'func': func, 'args': arguments, 'thisArg': object });
+                result.__chain__ = chainAll;
+                return result;
+              }
+              return func.apply(object, arrayPush([this.value()], arguments));
+            };
+          }(func));
+        }
+      }
+      return object;
+    }
+
+    /**
+     * Reverts the `_` variable to its previous value and returns a reference to
+     * the `lodash` function.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @returns {Function} Returns the `lodash` function.
+     * @example
+     *
+     * var lodash = _.noConflict();
+     */
+    function noConflict() {
+      root._ = oldDash;
+      return this;
+    }
+
+    /**
+     * A no-operation function that returns `undefined` regardless of the
+     * arguments it receives.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @example
+     *
+     * var object = { 'user': 'fred' };
+     *
+     * _.noop(object) === undefined;
+     * // => true
+     */
+    function noop() {
+      // No operation performed.
+    }
+
+    /**
+     * Creates a function that returns the property value at `path` on a
+     * given object.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Array|string} path The path of the property to get.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var objects = [
+     *   { 'a': { 'b': { 'c': 2 } } },
+     *   { 'a': { 'b': { 'c': 1 } } }
+     * ];
+     *
+     * _.map(objects, _.property('a.b.c'));
+     * // => [2, 1]
+     *
+     * _.pluck(_.sortBy(objects, _.property(['a', 'b', 'c'])), 'a.b.c');
+     * // => [1, 2]
+     */
+    function property(path) {
+      return isKey(path) ? baseProperty(path) : basePropertyDeep(path);
+    }
+
+    /**
+     * The opposite of `_.property`; this method creates a function that returns
+     * the property value at a given path on `object`.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Object} object The object to query.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var array = [0, 1, 2],
+     *     object = { 'a': array, 'b': array, 'c': array };
+     *
+     * _.map(['a[2]', 'c[0]'], _.propertyOf(object));
+     * // => [2, 0]
+     *
+     * _.map([['a', '2'], ['c', '0']], _.propertyOf(object));
+     * // => [2, 0]
+     */
+    function propertyOf(object) {
+      return function(path) {
+        return baseGet(object, toPath(path), (path + ''));
+      };
+    }
+
+    /**
+     * Creates an array of numbers (positive and/or negative) progressing from
+     * `start` up to, but not including, `end`. If `end` is not specified it's
+     * set to `start` with `start` then set to `0`. If `end` is less than `start`
+     * a zero-length range is created unless a negative `step` is specified.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {number} [start=0] The start of the range.
+     * @param {number} end The end of the range.
+     * @param {number} [step=1] The value to increment or decrement by.
+     * @returns {Array} Returns the new array of numbers.
+     * @example
+     *
+     * _.range(4);
+     * // => [0, 1, 2, 3]
+     *
+     * _.range(1, 5);
+     * // => [1, 2, 3, 4]
+     *
+     * _.range(0, 20, 5);
+     * // => [0, 5, 10, 15]
+     *
+     * _.range(0, -4, -1);
+     * // => [0, -1, -2, -3]
+     *
+     * _.range(1, 4, 0);
+     * // => [1, 1, 1]
+     *
+     * _.range(0);
+     * // => []
+     */
+    function range(start, end, step) {
+      if (step && isIterateeCall(start, end, step)) {
+        end = step = undefined;
+      }
+      start = +start || 0;
+      step = step == null ? 1 : (+step || 0);
+
+      if (end == null) {
+        end = start;
+        start = 0;
+      } else {
+        end = +end || 0;
+      }
+      // Use `Array(length)` so engines like Chakra and V8 avoid slower modes.
+      // See https://youtu.be/XAqIpGU8ZZk#t=17m25s for more details.
+      var index = -1,
+          length = nativeMax(nativeCeil((end - start) / (step || 1)), 0),
+          result = Array(length);
+
+      while (++index < length) {
+        result[index] = start;
+        start += step;
+      }
+      return result;
+    }
+
+    /**
+     * Invokes the iteratee function `n` times, returning an array of the results
+     * of each invocation. The `iteratee` is bound to `thisArg` and invoked with
+     * one argument; (index).
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {number} n The number of times to invoke `iteratee`.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the array of results.
+     * @example
+     *
+     * var diceRolls = _.times(3, _.partial(_.random, 1, 6, false));
+     * // => [3, 6, 4]
+     *
+     * _.times(3, function(n) {
+     *   mage.castSpell(n);
+     * });
+     * // => invokes `mage.castSpell(n)` three times with `n` of `0`, `1`, and `2`
+     *
+     * _.times(3, function(n) {
+     *   this.cast(n);
+     * }, mage);
+     * // => also invokes `mage.castSpell(n)` three times
+     */
+    function times(n, iteratee, thisArg) {
+      n = nativeFloor(n);
+
+      // Exit early to avoid a JSC JIT bug in Safari 8
+      // where `Array(0)` is treated as `Array(1)`.
+      if (n < 1 || !nativeIsFinite(n)) {
+        return [];
+      }
+      var index = -1,
+          result = Array(nativeMin(n, MAX_ARRAY_LENGTH));
+
+      iteratee = bindCallback(iteratee, thisArg, 1);
+      while (++index < n) {
+        if (index < MAX_ARRAY_LENGTH) {
+          result[index] = iteratee(index);
+        } else {
+          iteratee(index);
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Generates a unique ID. If `prefix` is provided the ID is appended to it.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
      * @param {string} [prefix] The value to prefix the ID with.
      * @returns {string} Returns the unique ID.
      * @example
@@ -6390,153 +11588,292 @@
      */
     function uniqueId(prefix) {
       var id = ++idCounter;
-      return String(prefix == null ? '' : prefix) + id;
-    }
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates a `lodash` object that wraps the given value with explicit
-     * method chaining enabled.
-     *
-     * @static
-     * @memberOf _
-     * @category Chaining
-     * @param {*} value The value to wrap.
-     * @returns {Object} Returns the wrapper object.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36 },
-     *   { 'name': 'fred',    'age': 40 },
-     *   { 'name': 'pebbles', 'age': 1 }
+      return baseToString(prefix) + id;
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Adds two numbers.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {number} augend The first number to add.
+     * @param {number} addend The second number to add.
+     * @returns {number} Returns the sum.
+     * @example
+     *
+     * _.add(6, 4);
+     * // => 10
+     */
+    function add(augend, addend) {
+      return (+augend || 0) + (+addend || 0);
+    }
+
+    /**
+     * Calculates `n` rounded up to `precision`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {number} n The number to round up.
+     * @param {number} [precision=0] The precision to round up to.
+     * @returns {number} Returns the rounded up number.
+     * @example
+     *
+     * _.ceil(4.006);
+     * // => 5
+     *
+     * _.ceil(6.004, 2);
+     * // => 6.01
+     *
+     * _.ceil(6040, -2);
+     * // => 6100
+     */
+    var ceil = createRound('ceil');
+
+    /**
+     * Calculates `n` rounded down to `precision`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {number} n The number to round down.
+     * @param {number} [precision=0] The precision to round down to.
+     * @returns {number} Returns the rounded down number.
+     * @example
+     *
+     * _.floor(4.006);
+     * // => 4
+     *
+     * _.floor(0.046, 2);
+     * // => 0.04
+     *
+     * _.floor(4060, -2);
+     * // => 4000
+     */
+    var floor = createRound('floor');
+
+    /**
+     * Gets the maximum value of `collection`. If `collection` is empty or falsey
+     * `-Infinity` is returned. If an iteratee function is provided it's invoked
+     * for each value in `collection` to generate the criterion by which the value
+     * is ranked. The `iteratee` is bound to `thisArg` and invoked with three
+     * arguments: (value, index, collection).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {*} Returns the maximum value.
+     * @example
+     *
+     * _.max([4, 2, 8, 6]);
+     * // => 8
+     *
+     * _.max([]);
+     * // => -Infinity
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 40 }
      * ];
      *
-     * var youngest = _.chain(characters)
-     *     .sortBy('age')
-     *     .map(function(chr) { return chr.name + ' is ' + chr.age; })
-     *     .first()
-     *     .value();
-     * // => 'pebbles is 1'
-     */
-    function chain(value) {
-      value = new lodashWrapper(value);
-      value.__chain__ = true;
-      return value;
-    }
-
-    /**
-     * Invokes `interceptor` with the `value` as the first argument and then
-     * returns `value`. The purpose of this method is to "tap into" a method
-     * chain in order to perform operations on intermediate results within
-     * the chain.
-     *
-     * @static
-     * @memberOf _
-     * @category Chaining
-     * @param {*} value The value to provide to `interceptor`.
-     * @param {Function} interceptor The function to invoke.
-     * @returns {*} Returns `value`.
-     * @example
-     *
-     * _([1, 2, 3, 4])
-     *  .tap(function(array) { array.pop(); })
-     *  .reverse()
-     *  .value();
-     * // => [3, 2, 1]
-     */
-    function tap(value, interceptor) {
-      interceptor(value);
-      return value;
-    }
-
-    /**
-     * Enables explicit method chaining on the wrapper object.
-     *
-     * @name chain
-     * @memberOf _
-     * @category Chaining
-     * @returns {*} Returns the wrapper object.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * _.max(users, function(chr) {
+     *   return chr.age;
+     * });
+     * // => { 'user': 'fred', 'age': 40 }
+     *
+     * // using the `_.property` callback shorthand
+     * _.max(users, 'age');
+     * // => { 'user': 'fred', 'age': 40 }
+     */
+    var max = createExtremum(gt, NEGATIVE_INFINITY);
+
+    /**
+     * Gets the minimum value of `collection`. If `collection` is empty or falsey
+     * `Infinity` is returned. If an iteratee function is provided it's invoked
+     * for each value in `collection` to generate the criterion by which the value
+     * is ranked. The `iteratee` is bound to `thisArg` and invoked with three
+     * arguments: (value, index, collection).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {*} Returns the minimum value.
+     * @example
+     *
+     * _.min([4, 2, 8, 6]);
+     * // => 2
+     *
+     * _.min([]);
+     * // => Infinity
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 40 }
      * ];
      *
-     * // without explicit chaining
-     * _(characters).first();
-     * // => { 'name': 'barney', 'age': 36 }
-     *
-     * // with explicit chaining
-     * _(characters).chain()
-     *   .first()
-     *   .pick('age')
-     *   .value();
-     * // => { 'age': 36 }
-     */
-    function wrapperChain() {
-      this.__chain__ = true;
-      return this;
-    }
-
-    /**
-     * Produces the `toString` result of the wrapped value.
-     *
-     * @name toString
-     * @memberOf _
-     * @category Chaining
-     * @returns {string} Returns the string result.
-     * @example
-     *
-     * _([1, 2, 3]).toString();
-     * // => '1,2,3'
-     */
-    function wrapperToString() {
-      return String(this.__wrapped__);
-    }
-
-    /**
-     * Extracts the wrapped value.
-     *
-     * @name valueOf
-     * @memberOf _
-     * @alias value
-     * @category Chaining
-     * @returns {*} Returns the wrapped value.
-     * @example
-     *
-     * _([1, 2, 3]).valueOf();
-     * // => [1, 2, 3]
-     */
-    function wrapperValueOf() {
-      return this.__wrapped__;
-    }
-
-    /*--------------------------------------------------------------------------*/
-
-    // add functions that return wrapped values when chaining
+     * _.min(users, function(chr) {
+     *   return chr.age;
+     * });
+     * // => { 'user': 'barney', 'age': 36 }
+     *
+     * // using the `_.property` callback shorthand
+     * _.min(users, 'age');
+     * // => { 'user': 'barney', 'age': 36 }
+     */
+    var min = createExtremum(lt, POSITIVE_INFINITY);
+
+    /**
+     * Calculates `n` rounded to `precision`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {number} n The number to round.
+     * @param {number} [precision=0] The precision to round to.
+     * @returns {number} Returns the rounded number.
+     * @example
+     *
+     * _.round(4.006);
+     * // => 4
+     *
+     * _.round(4.006, 2);
+     * // => 4.01
+     *
+     * _.round(4060, -2);
+     * // => 4100
+     */
+    var round = createRound('round');
+
+    /**
+     * Gets the sum of the values in `collection`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {number} Returns the sum.
+     * @example
+     *
+     * _.sum([4, 6]);
+     * // => 10
+     *
+     * _.sum({ 'a': 4, 'b': 6 });
+     * // => 10
+     *
+     * var objects = [
+     *   { 'n': 4 },
+     *   { 'n': 6 }
+     * ];
+     *
+     * _.sum(objects, function(object) {
+     *   return object.n;
+     * });
+     * // => 10
+     *
+     * // using the `_.property` callback shorthand
+     * _.sum(objects, 'n');
+     * // => 10
+     */
+    function sum(collection, iteratee, thisArg) {
+      if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
+        iteratee = undefined;
+      }
+      iteratee = getCallback(iteratee, thisArg, 3);
+      return iteratee.length == 1
+        ? arraySum(isArray(collection) ? collection : toIterable(collection), iteratee)
+        : baseSum(collection, iteratee);
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    // Ensure wrappers are instances of `baseLodash`.
+    lodash.prototype = baseLodash.prototype;
+
+    LodashWrapper.prototype = baseCreate(baseLodash.prototype);
+    LodashWrapper.prototype.constructor = LodashWrapper;
+
+    LazyWrapper.prototype = baseCreate(baseLodash.prototype);
+    LazyWrapper.prototype.constructor = LazyWrapper;
+
+    // Add functions to the `Map` cache.
+    MapCache.prototype['delete'] = mapDelete;
+    MapCache.prototype.get = mapGet;
+    MapCache.prototype.has = mapHas;
+    MapCache.prototype.set = mapSet;
+
+    // Add functions to the `Set` cache.
+    SetCache.prototype.push = cachePush;
+
+    // Assign cache to `_.memoize`.
+    memoize.Cache = MapCache;
+
+    // Add functions that return wrapped values when chaining.
     lodash.after = after;
+    lodash.ary = ary;
     lodash.assign = assign;
     lodash.at = at;
+    lodash.before = before;
     lodash.bind = bind;
     lodash.bindAll = bindAll;
     lodash.bindKey = bindKey;
+    lodash.callback = callback;
     lodash.chain = chain;
+    lodash.chunk = chunk;
     lodash.compact = compact;
-    lodash.compose = compose;
     lodash.constant = constant;
     lodash.countBy = countBy;
     lodash.create = create;
-    lodash.createCallback = createCallback;
     lodash.curry = curry;
+    lodash.curryRight = curryRight;
     lodash.debounce = debounce;
     lodash.defaults = defaults;
+    lodash.defaultsDeep = defaultsDeep;
     lodash.defer = defer;
     lodash.delay = delay;
     lodash.difference = difference;
+    lodash.drop = drop;
+    lodash.dropRight = dropRight;
+    lodash.dropRightWhile = dropRightWhile;
+    lodash.dropWhile = dropWhile;
+    lodash.fill = fill;
     lodash.filter = filter;
     lodash.flatten = flatten;
+    lodash.flattenDeep = flattenDeep;
+    lodash.flow = flow;
+    lodash.flowRight = flowRight;
     lodash.forEach = forEach;
     lodash.forEachRight = forEachRight;
     lodash.forIn = forIn;
@@ -6551,65 +11888,100 @@
     lodash.invert = invert;
     lodash.invoke = invoke;
     lodash.keys = keys;
+    lodash.keysIn = keysIn;
     lodash.map = map;
+    lodash.mapKeys = mapKeys;
     lodash.mapValues = mapValues;
-    lodash.max = max;
+    lodash.matches = matches;
+    lodash.matchesProperty = matchesProperty;
     lodash.memoize = memoize;
     lodash.merge = merge;
-    lodash.min = min;
+    lodash.method = method;
+    lodash.methodOf = methodOf;
+    lodash.mixin = mixin;
+    lodash.modArgs = modArgs;
+    lodash.negate = negate;
     lodash.omit = omit;
     lodash.once = once;
     lodash.pairs = pairs;
     lodash.partial = partial;
     lodash.partialRight = partialRight;
+    lodash.partition = partition;
     lodash.pick = pick;
     lodash.pluck = pluck;
     lodash.property = property;
+    lodash.propertyOf = propertyOf;
     lodash.pull = pull;
+    lodash.pullAt = pullAt;
     lodash.range = range;
+    lodash.rearg = rearg;
     lodash.reject = reject;
     lodash.remove = remove;
     lodash.rest = rest;
+    lodash.restParam = restParam;
+    lodash.set = set;
     lodash.shuffle = shuffle;
+    lodash.slice = slice;
     lodash.sortBy = sortBy;
+    lodash.sortByAll = sortByAll;
+    lodash.sortByOrder = sortByOrder;
+    lodash.spread = spread;
+    lodash.take = take;
+    lodash.takeRight = takeRight;
+    lodash.takeRightWhile = takeRightWhile;
+    lodash.takeWhile = takeWhile;
     lodash.tap = tap;
     lodash.throttle = throttle;
+    lodash.thru = thru;
     lodash.times = times;
     lodash.toArray = toArray;
+    lodash.toPlainObject = toPlainObject;
     lodash.transform = transform;
     lodash.union = union;
     lodash.uniq = uniq;
+    lodash.unzip = unzip;
+    lodash.unzipWith = unzipWith;
     lodash.values = values;
+    lodash.valuesIn = valuesIn;
     lodash.where = where;
     lodash.without = without;
     lodash.wrap = wrap;
     lodash.xor = xor;
     lodash.zip = zip;
     lodash.zipObject = zipObject;
-
-    // add aliases
+    lodash.zipWith = zipWith;
+
+    // Add aliases.
+    lodash.backflow = flowRight;
     lodash.collect = map;
-    lodash.drop = rest;
+    lodash.compose = flowRight;
     lodash.each = forEach;
     lodash.eachRight = forEachRight;
     lodash.extend = assign;
+    lodash.iteratee = callback;
     lodash.methods = functions;
     lodash.object = zipObject;
     lodash.select = filter;
     lodash.tail = rest;
     lodash.unique = uniq;
-    lodash.unzip = zip;
-
-    // add functions to `lodash.prototype`
-    mixin(lodash);
-
-    /*--------------------------------------------------------------------------*/
-
-    // add functions that return unwrapped values when chaining
+
+    // Add functions to `lodash.prototype`.
+    mixin(lodash, lodash);
+
+    /*------------------------------------------------------------------------*/
+
+    // Add functions that return unwrapped values when chaining.
+    lodash.add = add;
+    lodash.attempt = attempt;
+    lodash.camelCase = camelCase;
+    lodash.capitalize = capitalize;
+    lodash.ceil = ceil;
     lodash.clone = clone;
     lodash.cloneDeep = cloneDeep;
-    lodash.contains = contains;
+    lodash.deburr = deburr;
+    lodash.endsWith = endsWith;
     lodash.escape = escape;
+    lodash.escapeRegExp = escapeRegExp;
     lodash.every = every;
     lodash.find = find;
     lodash.findIndex = findIndex;
@@ -6617,9 +11989,17 @@
     lodash.findLast = findLast;
     lodash.findLastIndex = findLastIndex;
     lodash.findLastKey = findLastKey;
+    lodash.findWhere = findWhere;
+    lodash.first = first;
+    lodash.floor = floor;
+    lodash.get = get;
+    lodash.gt = gt;
+    lodash.gte = gte;
     lodash.has = has;
     lodash.identity = identity;
+    lodash.includes = includes;
     lodash.indexOf = indexOf;
+    lodash.inRange = inRange;
     lodash.isArguments = isArguments;
     lodash.isArray = isArray;
     lodash.isBoolean = isBoolean;
@@ -6627,80 +12007,95 @@
     lodash.isElement = isElement;
     lodash.isEmpty = isEmpty;
     lodash.isEqual = isEqual;
+    lodash.isError = isError;
     lodash.isFinite = isFinite;
     lodash.isFunction = isFunction;
+    lodash.isMatch = isMatch;
     lodash.isNaN = isNaN;
+    lodash.isNative = isNative;
     lodash.isNull = isNull;
     lodash.isNumber = isNumber;
     lodash.isObject = isObject;
     lodash.isPlainObject = isPlainObject;
     lodash.isRegExp = isRegExp;
     lodash.isString = isString;
+    lodash.isTypedArray = isTypedArray;
     lodash.isUndefined = isUndefined;
+    lodash.kebabCase = kebabCase;
+    lodash.last = last;
     lodash.lastIndexOf = lastIndexOf;
-    lodash.mixin = mixin;
+    lodash.lt = lt;
+    lodash.lte = lte;
+    lodash.max = max;
+    lodash.min = min;
     lodash.noConflict = noConflict;
     lodash.noop = noop;
     lodash.now = now;
+    lodash.pad = pad;
+    lodash.padLeft = padLeft;
+    lodash.padRight = padRight;
     lodash.parseInt = parseInt;
     lodash.random = random;
     lodash.reduce = reduce;
     lodash.reduceRight = reduceRight;
+    lodash.repeat = repeat;
     lodash.result = result;
+    lodash.round = round;
     lodash.runInContext = runInContext;
     lodash.size = size;
+    lodash.snakeCase = snakeCase;
     lodash.some = some;
     lodash.sortedIndex = sortedIndex;
+    lodash.sortedLastIndex = sortedLastIndex;
+    lodash.startCase = startCase;
+    lodash.startsWith = startsWith;
+    lodash.sum = sum;
     lodash.template = template;
+    lodash.trim = trim;
+    lodash.trimLeft = trimLeft;
+    lodash.trimRight = trimRight;
+    lodash.trunc = trunc;
     lodash.unescape = unescape;
     lodash.uniqueId = uniqueId;
-
-    // add aliases
+    lodash.words = words;
+
+    // Add aliases.
     lodash.all = every;
     lodash.any = some;
+    lodash.contains = includes;
+    lodash.eq = isEqual;
     lodash.detect = find;
-    lodash.findWhere = find;
     lodash.foldl = reduce;
     lodash.foldr = reduceRight;
-    lodash.include = contains;
+    lodash.head = first;
+    lodash.include = includes;
     lodash.inject = reduce;
 
-    mixin(function() {
-      var source = {}
-      forOwn(lodash, function(func, methodName) {
+    mixin(lodash, (function() {
+      var source = {};
+      baseForOwn(lodash, function(func, methodName) {
         if (!lodash.prototype[methodName]) {
           source[methodName] = func;
         }
       });
       return source;
-    }(), false);
-
-    /*--------------------------------------------------------------------------*/
-
-    // add functions capable of returning wrapped and unwrapped values when chaining
-    lodash.first = first;
-    lodash.last = last;
+    }()), false);
+
+    /*------------------------------------------------------------------------*/
+
+    // Add functions capable of returning wrapped and unwrapped values when chaining.
     lodash.sample = sample;
 
-    // add aliases
-    lodash.take = first;
-    lodash.head = first;
-
-    forOwn(lodash, function(func, methodName) {
-      var callbackable = methodName !== 'sample';
-      if (!lodash.prototype[methodName]) {
-        lodash.prototype[methodName]= function(n, guard) {
-          var chainAll = this.__chain__,
-              result = func(this.__wrapped__, n, guard);
-
-          return !chainAll && (n == null || (guard && !(callbackable && typeof n == 'function')))
-            ? result
-            : new lodashWrapper(result, chainAll);
-        };
-      }
-    });
-
-    /*--------------------------------------------------------------------------*/
+    lodash.prototype.sample = function(n) {
+      if (!this.__chain__ && n == null) {
+        return sample(this.value());
+      }
+      return this.thru(function(value) {
+        return sample(value, n);
+      });
+    };
+
+    /*------------------------------------------------------------------------*/
 
     /**
      * The semantic version number.
@@ -6709,78 +12104,249 @@
      * @memberOf _
      * @type string
      */
-    lodash.VERSION = '2.4.2';
-
-    // add "Chaining" functions to the wrapper
-    lodash.prototype.chain = wrapperChain;
-    lodash.prototype.toString = wrapperToString;
-    lodash.prototype.value = wrapperValueOf;
-    lodash.prototype.valueOf = wrapperValueOf;
-
-    // add `Array` functions that return unwrapped values
-    forEach(['join', 'pop', 'shift'], function(methodName) {
-      var func = arrayRef[methodName];
-      lodash.prototype[methodName] = function() {
-        var chainAll = this.__chain__,
-            result = func.apply(this.__wrapped__, arguments);
-
-        return chainAll
-          ? new lodashWrapper(result, chainAll)
-          : result;
+    lodash.VERSION = VERSION;
+
+    // Assign default placeholders.
+    arrayEach(['bind', 'bindKey', 'curry', 'curryRight', 'partial', 'partialRight'], function(methodName) {
+      lodash[methodName].placeholder = lodash;
+    });
+
+    // Add `LazyWrapper` methods for `_.drop` and `_.take` variants.
+    arrayEach(['drop', 'take'], function(methodName, index) {
+      LazyWrapper.prototype[methodName] = function(n) {
+        var filtered = this.__filtered__;
+        if (filtered && !index) {
+          return new LazyWrapper(this);
+        }
+        n = n == null ? 1 : nativeMax(nativeFloor(n) || 0, 0);
+
+        var result = this.clone();
+        if (filtered) {
+          result.__takeCount__ = nativeMin(result.__takeCount__, n);
+        } else {
+          result.__views__.push({ 'size': n, 'type': methodName + (result.__dir__ < 0 ? 'Right' : '') });
+        }
+        return result;
+      };
+
+      LazyWrapper.prototype[methodName + 'Right'] = function(n) {
+        return this.reverse()[methodName](n).reverse();
+      };
+    });
+
+    // Add `LazyWrapper` methods that accept an `iteratee` value.
+    arrayEach(['filter', 'map', 'takeWhile'], function(methodName, index) {
+      var type = index + 1,
+          isFilter = type != LAZY_MAP_FLAG;
+
+      LazyWrapper.prototype[methodName] = function(iteratee, thisArg) {
+        var result = this.clone();
+        result.__iteratees__.push({ 'iteratee': getCallback(iteratee, thisArg, 1), 'type': type });
+        result.__filtered__ = result.__filtered__ || isFilter;
+        return result;
+      };
+    });
+
+    // Add `LazyWrapper` methods for `_.first` and `_.last`.
+    arrayEach(['first', 'last'], function(methodName, index) {
+      var takeName = 'take' + (index ? 'Right' : '');
+
+      LazyWrapper.prototype[methodName] = function() {
+        return this[takeName](1).value()[0];
+      };
+    });
+
+    // Add `LazyWrapper` methods for `_.initial` and `_.rest`.
+    arrayEach(['initial', 'rest'], function(methodName, index) {
+      var dropName = 'drop' + (index ? '' : 'Right');
+
+      LazyWrapper.prototype[methodName] = function() {
+        return this.__filtered__ ? new LazyWrapper(this) : this[dropName](1);
+      };
+    });
+
+    // Add `LazyWrapper` methods for `_.pluck` and `_.where`.
+    arrayEach(['pluck', 'where'], function(methodName, index) {
+      var operationName = index ? 'filter' : 'map',
+          createCallback = index ? baseMatches : property;
+
+      LazyWrapper.prototype[methodName] = function(value) {
+        return this[operationName](createCallback(value));
       };
     });
 
-    // add `Array` functions that return the existing wrapped value
-    forEach(['push', 'reverse', 'sort', 'unshift'], function(methodName) {
-      var func = arrayRef[methodName];
+    LazyWrapper.prototype.compact = function() {
+      return this.filter(identity);
+    };
+
+    LazyWrapper.prototype.reject = function(predicate, thisArg) {
+      predicate = getCallback(predicate, thisArg, 1);
+      return this.filter(function(value) {
+        return !predicate(value);
+      });
+    };
+
+    LazyWrapper.prototype.slice = function(start, end) {
+      start = start == null ? 0 : (+start || 0);
+
+      var result = this;
+      if (result.__filtered__ && (start > 0 || end < 0)) {
+        return new LazyWrapper(result);
+      }
+      if (start < 0) {
+        result = result.takeRight(-start);
+      } else if (start) {
+        result = result.drop(start);
+      }
+      if (end !== undefined) {
+        end = (+end || 0);
+        result = end < 0 ? result.dropRight(-end) : result.take(end - start);
+      }
+      return result;
+    };
+
+    LazyWrapper.prototype.takeRightWhile = function(predicate, thisArg) {
+      return this.reverse().takeWhile(predicate, thisArg).reverse();
+    };
+
+    LazyWrapper.prototype.toArray = function() {
+      return this.take(POSITIVE_INFINITY);
+    };
+
+    // Add `LazyWrapper` methods to `lodash.prototype`.
+    baseForOwn(LazyWrapper.prototype, function(func, methodName) {
+      var checkIteratee = /^(?:filter|map|reject)|While$/.test(methodName),
+          retUnwrapped = /^(?:first|last)$/.test(methodName),
+          lodashFunc = lodash[retUnwrapped ? ('take' + (methodName == 'last' ? 'Right' : '')) : methodName];
+
+      if (!lodashFunc) {
+        return;
+      }
       lodash.prototype[methodName] = function() {
-        func.apply(this.__wrapped__, arguments);
-        return this;
+        var args = retUnwrapped ? [1] : arguments,
+            chainAll = this.__chain__,
+            value = this.__wrapped__,
+            isHybrid = !!this.__actions__.length,
+            isLazy = value instanceof LazyWrapper,
+            iteratee = args[0],
+            useLazy = isLazy || isArray(value);
+
+        if (useLazy && checkIteratee && typeof iteratee == 'function' && iteratee.length != 1) {
+          // Avoid lazy use if the iteratee has a "length" value other than `1`.
+          isLazy = useLazy = false;
+        }
+        var interceptor = function(value) {
+          return (retUnwrapped && chainAll)
+            ? lodashFunc(value, 1)[0]
+            : lodashFunc.apply(undefined, arrayPush([value], args));
+        };
+
+        var action = { 'func': thru, 'args': [interceptor], 'thisArg': undefined },
+            onlyLazy = isLazy && !isHybrid;
+
+        if (retUnwrapped && !chainAll) {
+          if (onlyLazy) {
+            value = value.clone();
+            value.__actions__.push(action);
+            return func.call(value);
+          }
+          return lodashFunc.call(undefined, this.value())[0];
+        }
+        if (!retUnwrapped && useLazy) {
+          value = onlyLazy ? value : new LazyWrapper(this);
+          var result = func.apply(value, args);
+          result.__actions__.push(action);
+          return new LodashWrapper(result, chainAll);
+        }
+        return this.thru(interceptor);
       };
     });
 
-    // add `Array` functions that return new wrapped values
-    forEach(['concat', 'slice', 'splice'], function(methodName) {
-      var func = arrayRef[methodName];
+    // Add `Array` and `String` methods to `lodash.prototype`.
+    arrayEach(['join', 'pop', 'push', 'replace', 'shift', 'sort', 'splice', 'split', 'unshift'], function(methodName) {
+      var func = (/^(?:replace|split)$/.test(methodName) ? stringProto : arrayProto)[methodName],
+          chainName = /^(?:push|sort|unshift)$/.test(methodName) ? 'tap' : 'thru',
+          retUnwrapped = /^(?:join|pop|replace|shift)$/.test(methodName);
+
       lodash.prototype[methodName] = function() {
-        return new lodashWrapper(func.apply(this.__wrapped__, arguments), this.__chain__);
+        var args = arguments;
+        if (retUnwrapped && !this.__chain__) {
+          return func.apply(this.value(), args);
+        }
+        return this[chainName](function(value) {
+          return func.apply(value, args);
+        });
       };
     });
 
+    // Map minified function names to their real names.
+    baseForOwn(LazyWrapper.prototype, function(func, methodName) {
+      var lodashFunc = lodash[methodName];
+      if (lodashFunc) {
+        var key = (lodashFunc.name + ''),
+            names = realNames[key] || (realNames[key] = []);
+
+        names.push({ 'name': methodName, 'func': lodashFunc });
+      }
+    });
+
+    realNames[createHybridWrapper(undefined, BIND_KEY_FLAG).name] = [{ 'name': 'wrapper', 'func': undefined }];
+
+    // Add functions to the lazy wrapper.
+    LazyWrapper.prototype.clone = lazyClone;
+    LazyWrapper.prototype.reverse = lazyReverse;
+    LazyWrapper.prototype.value = lazyValue;
+
+    // Add chaining functions to the `lodash` wrapper.
+    lodash.prototype.chain = wrapperChain;
+    lodash.prototype.commit = wrapperCommit;
+    lodash.prototype.concat = wrapperConcat;
+    lodash.prototype.plant = wrapperPlant;
+    lodash.prototype.reverse = wrapperReverse;
+    lodash.prototype.toString = wrapperToString;
+    lodash.prototype.run = lodash.prototype.toJSON = lodash.prototype.valueOf = lodash.prototype.value = wrapperValue;
+
+    // Add function aliases to the `lodash` wrapper.
+    lodash.prototype.collect = lodash.prototype.map;
+    lodash.prototype.head = lodash.prototype.first;
+    lodash.prototype.select = lodash.prototype.filter;
+    lodash.prototype.tail = lodash.prototype.rest;
+
     return lodash;
   }
 
   /*--------------------------------------------------------------------------*/
 
-  // expose Lo-Dash
+  // Export lodash.
   var _ = runInContext();
 
-  // some AMD build optimizers like r.js check for condition patterns like the following:
+  // Some AMD build optimizers like r.js check for condition patterns like the following:
   if (typeof define == 'function' && typeof define.amd == 'object' && define.amd) {
-    // Expose Lo-Dash to the global object even when an AMD loader is present in
-    // case Lo-Dash is loaded with a RequireJS shim config.
-    // See http://requirejs.org/docs/api.html#config-shim
+    // Expose lodash to the global object when an AMD loader is present to avoid
+    // errors in cases where lodash is loaded by a script tag and not intended
+    // as an AMD module. See http://requirejs.org/docs/errors.html#mismatch for
+    // more details.
     root._ = _;
 
-    // define as an anonymous module so, through path mapping, it can be
-    // referenced as the "underscore" module
+    // Define as an anonymous module so, through path mapping, it can be
+    // referenced as the "underscore" module.
     define(function() {
       return _;
     });
   }
-  // check for `exports` after `define` in case a build optimizer adds an `exports` object
+  // Check for `exports` after `define` in case a build optimizer adds an `exports` object.
   else if (freeExports && freeModule) {
-    // in Node.js or RingoJS
+    // Export for Node.js or RingoJS.
     if (moduleExports) {
       (freeModule.exports = _)._ = _;
     }
-    // in Narwhal or Rhino -require
+    // Export for Rhino with CommonJS support.
     else {
       freeExports._ = _;
     }
   }
   else {
-    // in a browser or Rhino
+    // Export for a browser or Rhino.
     root._ = _;
   }
 }.call(this));
--- a/server/python/django/renkanmanager/static/renkanmanager/lib/backbone-relational/backbone-relational.js	Wed Sep 09 15:05:30 2015 +0200
+++ b/server/python/django/renkanmanager/static/renkanmanager/lib/backbone-relational/backbone-relational.js	Wed Sep 09 15:18:53 2015 +0200
@@ -1,6 +1,6 @@
 /* vim: set tabstop=4 softtabstop=4 shiftwidth=4 noexpandtab: */
 /**
- * Backbone-relational.js 0.9.0
+ * Backbone-relational.js 0.10.0
  * (c) 2011-2014 Paul Uithol and contributors (https://github.com/PaulUithol/Backbone-relational/graphs/contributors)
  *
  * Backbone-relational may be freely distributed under the MIT license; see the accompanying LICENSE.txt.
@@ -1022,9 +1022,8 @@
 					}
 					else {
 						// If `merge` is true, update models here, instead of during update.
-						model = this.relatedModel.findOrCreate( attributes,
-							_.extend( { merge: true }, options, { create: this.options.createModels } )
-						);
+						model = ( _.isObject( attributes ) && options.parse && this.relatedModel.prototype.parse ) ?
+							this.relatedModel.prototype.parse( _.clone( attributes ), options ) : attributes;
 					}
 
 					model && toAdd.push( model );
@@ -1037,9 +1036,9 @@
 					related = this._prepareCollection();
 				}
 
-				// By now, both `merge` and `parse` will already have been executed for models if they were specified.
-				// Disable them to prevent additional calls.
-				related.set( toAdd, _.defaults( { merge: false, parse: false }, options ) );
+				// By now, `parse` will already have been executed just above for models if specified.
+				// Disable to prevent additional calls.
+				related.set( toAdd, _.defaults( { parse: false }, options ) );
 			}
 
 			// Remove entries from `keyIds` that were already part of the relation (and are thus 'unchanged')
@@ -1238,7 +1237,7 @@
 				var dit = this,
 					args = arguments;
 
-				if ( !Backbone.Relational.eventQueue.isLocked() ) {
+				if ( !Backbone.Relational.eventQueue.isBlocked() ) {
 					// If we're not in a more complicated nested scenario, fire the change event right away
 					Backbone.Model.prototype.trigger.apply( dit, args );
 				}
@@ -1494,12 +1493,16 @@
 				}
 			}
 
-			return $.when.apply( null, requests ).then(
+			return this.deferArray(requests).then(
 				function() {
 					return Backbone.Model.prototype.get.call( dit, attr );
 				}
 			);
 		},
+		
+		deferArray: function(deferArray) {
+			return Backbone.$.when.apply(null, deferArray);
+		},
 
 		set: function( key, value, options ) {
 			Backbone.Relational.eventQueue.block();
@@ -1827,7 +1830,7 @@
 		findOrCreate: function( attributes, options ) {
 			options || ( options = {} );
 			var parsedAttributes = ( _.isObject( attributes ) && options.parse && this.prototype.parse ) ?
-				this.prototype.parse( _.clone( attributes ) ) : attributes;
+				this.prototype.parse( _.clone( attributes ), options ) : attributes;
 
 			// If specified, use a custom `find` function to match up existing models to the given attributes.
 			// Otherwise, try to find an instance of 'this' model type in the store
@@ -1974,20 +1977,16 @@
 	};
 
 	/**
-	 * Override 'Backbone.Collection.remove' to trigger 'relational:remove'.
+	 * Override 'Backbone.Collection._removeModels' to trigger 'relational:remove'.
 	 */
-	var remove = Backbone.Collection.prototype.__remove = Backbone.Collection.prototype.remove;
-	Backbone.Collection.prototype.remove = function( models, options ) {
+	var _removeModels = Backbone.Collection.prototype.___removeModels = Backbone.Collection.prototype._removeModels;
+	Backbone.Collection.prototype._removeModels = function( models, options ) {
 		// Short-circuit if this Collection doesn't hold RelationalModels
 		if ( !( this.model.prototype instanceof Backbone.RelationalModel ) ) {
-			return remove.call( this, models, options );
+			return _removeModels.call( this, models, options );
 		}
 
-		var singular = !_.isArray( models ),
-			toRemove = [];
-
-		models = singular ? ( models ? [ models ] : [] ) : _.clone( models );
-		options || ( options = {} );
+		var toRemove = [];
 
 		//console.debug('calling remove on coll=%o; models=%o, options=%o', this, models, options );
 		_.each( models, function( model ) {
@@ -1995,7 +1994,7 @@
 			model && toRemove.push( model );
 		}, this );
 
-		var result = remove.call( this, singular ? ( toRemove.length ? toRemove[ 0 ] : null ) : toRemove, options );
+		var result = _removeModels.call( this, toRemove, options );
 
 		_.each( toRemove, function( model ) {
 			this.trigger( 'relational:remove', model, this, options );
--- a/server/python/django/renkanmanager/static/renkanmanager/lib/backbone/backbone.js	Wed Sep 09 15:05:30 2015 +0200
+++ b/server/python/django/renkanmanager/static/renkanmanager/lib/backbone/backbone.js	Wed Sep 09 15:18:53 2015 +0200
@@ -1,11 +1,16 @@
-//     Backbone.js 1.1.2
+//     Backbone.js 1.2.3
 
-//     (c) 2010-2014 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
+//     (c) 2010-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 //     Backbone may be freely distributed under the MIT license.
 //     For all details and documentation:
 //     http://backbonejs.org
 
-(function(root, factory) {
+(function(factory) {
+
+  // Establish the root object, `window` (`self`) in the browser, or `global` on the server.
+  // We use `self` instead of `window` for `WebWorker` support.
+  var root = (typeof self == 'object' && self.self == self && self) ||
+            (typeof global == 'object' && global.global == global && global);
 
   // Set up Backbone appropriately for the environment. Start with AMD.
   if (typeof define === 'function' && define.amd) {
@@ -17,15 +22,16 @@
 
   // Next for Node.js or CommonJS. jQuery may not be needed as a module.
   } else if (typeof exports !== 'undefined') {
-    var _ = require('underscore');
-    factory(root, exports, _);
+    var _ = require('underscore'), $;
+    try { $ = require('jquery'); } catch(e) {}
+    factory(root, exports, _, $);
 
   // Finally, as a browser global.
   } else {
     root.Backbone = factory(root, {}, root._, (root.jQuery || root.Zepto || root.ender || root.$));
   }
 
-}(this, function(root, Backbone, _, $) {
+}(function(root, Backbone, _, $) {
 
   // Initial Setup
   // -------------
@@ -34,14 +40,11 @@
   // restored later on, if `noConflict` is used.
   var previousBackbone = root.Backbone;
 
-  // Create local references to array methods we'll want to use later.
-  var array = [];
-  var push = array.push;
-  var slice = array.slice;
-  var splice = array.splice;
+  // Create a local reference to a common array method we'll want to use later.
+  var slice = Array.prototype.slice;
 
   // Current version of the library. Keep in sync with `package.json`.
-  Backbone.VERSION = '1.1.2';
+  Backbone.VERSION = '1.2.3';
 
   // For Backbone's purposes, jQuery, Zepto, Ender, or My Library (kidding) owns
   // the `$` variable.
@@ -60,17 +63,65 @@
   Backbone.emulateHTTP = false;
 
   // Turn on `emulateJSON` to support legacy servers that can't deal with direct
-  // `application/json` requests ... will encode the body as
+  // `application/json` requests ... this will encode the body as
   // `application/x-www-form-urlencoded` instead and will send the model in a
   // form param named `model`.
   Backbone.emulateJSON = false;
 
+  // Proxy Backbone class methods to Underscore functions, wrapping the model's
+  // `attributes` object or collection's `models` array behind the scenes.
+  //
+  // collection.filter(function(model) { return model.get('age') > 10 });
+  // collection.each(this.addView);
+  //
+  // `Function#apply` can be slow so we use the method's arg count, if we know it.
+  var addMethod = function(length, method, attribute) {
+    switch (length) {
+      case 1: return function() {
+        return _[method](this[attribute]);
+      };
+      case 2: return function(value) {
+        return _[method](this[attribute], value);
+      };
+      case 3: return function(iteratee, context) {
+        return _[method](this[attribute], cb(iteratee, this), context);
+      };
+      case 4: return function(iteratee, defaultVal, context) {
+        return _[method](this[attribute], cb(iteratee, this), defaultVal, context);
+      };
+      default: return function() {
+        var args = slice.call(arguments);
+        args.unshift(this[attribute]);
+        return _[method].apply(_, args);
+      };
+    }
+  };
+  var addUnderscoreMethods = function(Class, methods, attribute) {
+    _.each(methods, function(length, method) {
+      if (_[method]) Class.prototype[method] = addMethod(length, method, attribute);
+    });
+  };
+
+  // Support `collection.sortBy('attr')` and `collection.findWhere({id: 1})`.
+  var cb = function(iteratee, instance) {
+    if (_.isFunction(iteratee)) return iteratee;
+    if (_.isObject(iteratee) && !instance._isModel(iteratee)) return modelMatcher(iteratee);
+    if (_.isString(iteratee)) return function(model) { return model.get(iteratee); };
+    return iteratee;
+  };
+  var modelMatcher = function(attrs) {
+    var matcher = _.matches(attrs);
+    return function(model) {
+      return matcher(model.attributes);
+    };
+  };
+
   // Backbone.Events
   // ---------------
 
   // A module that can be mixed in to *any object* in order to provide it with
-  // custom events. You may bind with `on` or remove with `off` callback
-  // functions to an event; `trigger`-ing an event fires all callbacks in
+  // a custom event channel. You may bind a callback to an event with `on` or
+  // remove with `off`; `trigger`-ing an event fires all callbacks in
   // succession.
   //
   //     var object = {};
@@ -78,123 +129,234 @@
   //     object.on('expand', function(){ alert('expanded'); });
   //     object.trigger('expand');
   //
-  var Events = Backbone.Events = {
-
-    // Bind an event to a `callback` function. Passing `"all"` will bind
-    // the callback to all events fired.
-    on: function(name, callback, context) {
-      if (!eventsApi(this, 'on', name, [callback, context]) || !callback) return this;
-      this._events || (this._events = {});
-      var events = this._events[name] || (this._events[name] = []);
-      events.push({callback: callback, context: context, ctx: context || this});
-      return this;
-    },
-
-    // Bind an event to only be triggered a single time. After the first time
-    // the callback is invoked, it will be removed.
-    once: function(name, callback, context) {
-      if (!eventsApi(this, 'once', name, [callback, context]) || !callback) return this;
-      var self = this;
-      var once = _.once(function() {
-        self.off(name, once);
-        callback.apply(this, arguments);
-      });
-      once._callback = callback;
-      return this.on(name, once, context);
-    },
-
-    // Remove one or many callbacks. If `context` is null, removes all
-    // callbacks with that function. If `callback` is null, removes all
-    // callbacks for the event. If `name` is null, removes all bound
-    // callbacks for all events.
-    off: function(name, callback, context) {
-      var retain, ev, events, names, i, l, j, k;
-      if (!this._events || !eventsApi(this, 'off', name, [callback, context])) return this;
-      if (!name && !callback && !context) {
-        this._events = void 0;
-        return this;
-      }
-      names = name ? [name] : _.keys(this._events);
-      for (i = 0, l = names.length; i < l; i++) {
-        name = names[i];
-        if (events = this._events[name]) {
-          this._events[name] = retain = [];
-          if (callback || context) {
-            for (j = 0, k = events.length; j < k; j++) {
-              ev = events[j];
-              if ((callback && callback !== ev.callback && callback !== ev.callback._callback) ||
-                  (context && context !== ev.context)) {
-                retain.push(ev);
-              }
-            }
-          }
-          if (!retain.length) delete this._events[name];
-        }
-      }
-
-      return this;
-    },
-
-    // Trigger one or many events, firing all bound callbacks. Callbacks are
-    // passed the same arguments as `trigger` is, apart from the event name
-    // (unless you're listening on `"all"`, which will cause your callback to
-    // receive the true name of the event as the first argument).
-    trigger: function(name) {
-      if (!this._events) return this;
-      var args = slice.call(arguments, 1);
-      if (!eventsApi(this, 'trigger', name, args)) return this;
-      var events = this._events[name];
-      var allEvents = this._events.all;
-      if (events) triggerEvents(events, args);
-      if (allEvents) triggerEvents(allEvents, arguments);
-      return this;
-    },
-
-    // Tell this object to stop listening to either specific events ... or
-    // to every object it's currently listening to.
-    stopListening: function(obj, name, callback) {
-      var listeningTo = this._listeningTo;
-      if (!listeningTo) return this;
-      var remove = !name && !callback;
-      if (!callback && typeof name === 'object') callback = this;
-      if (obj) (listeningTo = {})[obj._listenId] = obj;
-      for (var id in listeningTo) {
-        obj = listeningTo[id];
-        obj.off(name, callback, this);
-        if (remove || _.isEmpty(obj._events)) delete this._listeningTo[id];
-      }
-      return this;
-    }
-
-  };
+  var Events = Backbone.Events = {};
 
   // Regular expression used to split event strings.
   var eventSplitter = /\s+/;
 
-  // Implement fancy features of the Events API such as multiple event
-  // names `"change blur"` and jQuery-style event maps `{change: action}`
-  // in terms of the existing API.
-  var eventsApi = function(obj, action, name, rest) {
-    if (!name) return true;
+  // Iterates over the standard `event, callback` (as well as the fancy multiple
+  // space-separated events `"change blur", callback` and jQuery-style event
+  // maps `{event: callback}`).
+  var eventsApi = function(iteratee, events, name, callback, opts) {
+    var i = 0, names;
+    if (name && typeof name === 'object') {
+      // Handle event maps.
+      if (callback !== void 0 && 'context' in opts && opts.context === void 0) opts.context = callback;
+      for (names = _.keys(name); i < names.length ; i++) {
+        events = eventsApi(iteratee, events, names[i], name[names[i]], opts);
+      }
+    } else if (name && eventSplitter.test(name)) {
+      // Handle space separated event names by delegating them individually.
+      for (names = name.split(eventSplitter); i < names.length; i++) {
+        events = iteratee(events, names[i], callback, opts);
+      }
+    } else {
+      // Finally, standard events.
+      events = iteratee(events, name, callback, opts);
+    }
+    return events;
+  };
+
+  // Bind an event to a `callback` function. Passing `"all"` will bind
+  // the callback to all events fired.
+  Events.on = function(name, callback, context) {
+    return internalOn(this, name, callback, context);
+  };
 
-    // Handle event maps.
-    if (typeof name === 'object') {
-      for (var key in name) {
-        obj[action].apply(obj, [key, name[key]].concat(rest));
-      }
-      return false;
+  // Guard the `listening` argument from the public API.
+  var internalOn = function(obj, name, callback, context, listening) {
+    obj._events = eventsApi(onApi, obj._events || {}, name, callback, {
+        context: context,
+        ctx: obj,
+        listening: listening
+    });
+
+    if (listening) {
+      var listeners = obj._listeners || (obj._listeners = {});
+      listeners[listening.id] = listening;
+    }
+
+    return obj;
+  };
+
+  // Inversion-of-control versions of `on`. Tell *this* object to listen to
+  // an event in another object... keeping track of what it's listening to
+  // for easier unbinding later.
+  Events.listenTo =  function(obj, name, callback) {
+    if (!obj) return this;
+    var id = obj._listenId || (obj._listenId = _.uniqueId('l'));
+    var listeningTo = this._listeningTo || (this._listeningTo = {});
+    var listening = listeningTo[id];
+
+    // This object is not listening to any other events on `obj` yet.
+    // Setup the necessary references to track the listening callbacks.
+    if (!listening) {
+      var thisId = this._listenId || (this._listenId = _.uniqueId('l'));
+      listening = listeningTo[id] = {obj: obj, objId: id, id: thisId, listeningTo: listeningTo, count: 0};
     }
 
-    // Handle space separated event names.
-    if (eventSplitter.test(name)) {
-      var names = name.split(eventSplitter);
-      for (var i = 0, l = names.length; i < l; i++) {
-        obj[action].apply(obj, [names[i]].concat(rest));
+    // Bind callbacks on obj, and keep track of them on listening.
+    internalOn(obj, name, callback, this, listening);
+    return this;
+  };
+
+  // The reducing API that adds a callback to the `events` object.
+  var onApi = function(events, name, callback, options) {
+    if (callback) {
+      var handlers = events[name] || (events[name] = []);
+      var context = options.context, ctx = options.ctx, listening = options.listening;
+      if (listening) listening.count++;
+
+      handlers.push({ callback: callback, context: context, ctx: context || ctx, listening: listening });
+    }
+    return events;
+  };
+
+  // Remove one or many callbacks. If `context` is null, removes all
+  // callbacks with that function. If `callback` is null, removes all
+  // callbacks for the event. If `name` is null, removes all bound
+  // callbacks for all events.
+  Events.off =  function(name, callback, context) {
+    if (!this._events) return this;
+    this._events = eventsApi(offApi, this._events, name, callback, {
+        context: context,
+        listeners: this._listeners
+    });
+    return this;
+  };
+
+  // Tell this object to stop listening to either specific events ... or
+  // to every object it's currently listening to.
+  Events.stopListening =  function(obj, name, callback) {
+    var listeningTo = this._listeningTo;
+    if (!listeningTo) return this;
+
+    var ids = obj ? [obj._listenId] : _.keys(listeningTo);
+
+    for (var i = 0; i < ids.length; i++) {
+      var listening = listeningTo[ids[i]];
+
+      // If listening doesn't exist, this object is not currently
+      // listening to obj. Break out early.
+      if (!listening) break;
+
+      listening.obj.off(name, callback, this);
+    }
+    if (_.isEmpty(listeningTo)) this._listeningTo = void 0;
+
+    return this;
+  };
+
+  // The reducing API that removes a callback from the `events` object.
+  var offApi = function(events, name, callback, options) {
+    if (!events) return;
+
+    var i = 0, listening;
+    var context = options.context, listeners = options.listeners;
+
+    // Delete all events listeners and "drop" events.
+    if (!name && !callback && !context) {
+      var ids = _.keys(listeners);
+      for (; i < ids.length; i++) {
+        listening = listeners[ids[i]];
+        delete listeners[listening.id];
+        delete listening.listeningTo[listening.objId];
       }
-      return false;
+      return;
     }
 
-    return true;
+    var names = name ? [name] : _.keys(events);
+    for (; i < names.length; i++) {
+      name = names[i];
+      var handlers = events[name];
+
+      // Bail out if there are no events stored.
+      if (!handlers) break;
+
+      // Replace events if there are any remaining.  Otherwise, clean up.
+      var remaining = [];
+      for (var j = 0; j < handlers.length; j++) {
+        var handler = handlers[j];
+        if (
+          callback && callback !== handler.callback &&
+            callback !== handler.callback._callback ||
+              context && context !== handler.context
+        ) {
+          remaining.push(handler);
+        } else {
+          listening = handler.listening;
+          if (listening && --listening.count === 0) {
+            delete listeners[listening.id];
+            delete listening.listeningTo[listening.objId];
+          }
+        }
+      }
+
+      // Update tail event if the list has any events.  Otherwise, clean up.
+      if (remaining.length) {
+        events[name] = remaining;
+      } else {
+        delete events[name];
+      }
+    }
+    if (_.size(events)) return events;
+  };
+
+  // Bind an event to only be triggered a single time. After the first time
+  // the callback is invoked, its listener will be removed. If multiple events
+  // are passed in using the space-separated syntax, the handler will fire
+  // once for each event, not once for a combination of all events.
+  Events.once =  function(name, callback, context) {
+    // Map the event into a `{event: once}` object.
+    var events = eventsApi(onceMap, {}, name, callback, _.bind(this.off, this));
+    return this.on(events, void 0, context);
+  };
+
+  // Inversion-of-control versions of `once`.
+  Events.listenToOnce =  function(obj, name, callback) {
+    // Map the event into a `{event: once}` object.
+    var events = eventsApi(onceMap, {}, name, callback, _.bind(this.stopListening, this, obj));
+    return this.listenTo(obj, events);
+  };
+
+  // Reduces the event callbacks into a map of `{event: onceWrapper}`.
+  // `offer` unbinds the `onceWrapper` after it has been called.
+  var onceMap = function(map, name, callback, offer) {
+    if (callback) {
+      var once = map[name] = _.once(function() {
+        offer(name, once);
+        callback.apply(this, arguments);
+      });
+      once._callback = callback;
+    }
+    return map;
+  };
+
+  // Trigger one or many events, firing all bound callbacks. Callbacks are
+  // passed the same arguments as `trigger` is, apart from the event name
+  // (unless you're listening on `"all"`, which will cause your callback to
+  // receive the true name of the event as the first argument).
+  Events.trigger =  function(name) {
+    if (!this._events) return this;
+
+    var length = Math.max(0, arguments.length - 1);
+    var args = Array(length);
+    for (var i = 0; i < length; i++) args[i] = arguments[i + 1];
+
+    eventsApi(triggerApi, this._events, name, void 0, args);
+    return this;
+  };
+
+  // Handles triggering the appropriate event callbacks.
+  var triggerApi = function(objEvents, name, cb, args) {
+    if (objEvents) {
+      var events = objEvents[name];
+      var allEvents = objEvents.all;
+      if (events && allEvents) allEvents = allEvents.slice();
+      if (events) triggerEvents(events, args);
+      if (allEvents) triggerEvents(allEvents, [name].concat(args));
+    }
+    return objEvents;
   };
 
   // A difficult-to-believe, but optimized internal dispatch function for
@@ -211,22 +373,6 @@
     }
   };
 
-  var listenMethods = {listenTo: 'on', listenToOnce: 'once'};
-
-  // Inversion-of-control versions of `on` and `once`. Tell *this* object to
-  // listen to an event in another object ... keeping track of what it's
-  // listening to.
-  _.each(listenMethods, function(implementation, method) {
-    Events[method] = function(obj, name, callback) {
-      var listeningTo = this._listeningTo || (this._listeningTo = {});
-      var id = obj._listenId || (obj._listenId = _.uniqueId('l'));
-      listeningTo[id] = obj;
-      if (!callback && typeof name === 'object') callback = this;
-      obj[implementation](name, callback, this);
-      return this;
-    };
-  });
-
   // Aliases for backwards compatibility.
   Events.bind   = Events.on;
   Events.unbind = Events.off;
@@ -248,7 +394,7 @@
   var Model = Backbone.Model = function(attributes, options) {
     var attrs = attributes || {};
     options || (options = {});
-    this.cid = _.uniqueId('c');
+    this.cid = _.uniqueId(this.cidPrefix);
     this.attributes = {};
     if (options.collection) this.collection = options.collection;
     if (options.parse) attrs = this.parse(attrs, options) || {};
@@ -271,6 +417,10 @@
     // CouchDB users may want to set this to `"_id"`.
     idAttribute: 'id',
 
+    // The prefix is used to create the client id which is used to identify models locally.
+    // You may want to override this if you're experiencing name clashes with model ids.
+    cidPrefix: 'c',
+
     // Initialize is an empty function by default. Override it with your own
     // initialization logic.
     initialize: function(){},
@@ -302,14 +452,19 @@
       return this.get(attr) != null;
     },
 
+    // Special-cased proxy to underscore's `_.matches` method.
+    matches: function(attrs) {
+      return !!_.iteratee(attrs, this)(this.attributes);
+    },
+
     // Set a hash of model attributes on the object, firing `"change"`. This is
     // the core primitive operation of a model, updating the data and notifying
     // anyone who needs to know about the change in state. The heart of the beast.
     set: function(key, val, options) {
-      var attr, attrs, unset, changes, silent, changing, prev, current;
       if (key == null) return this;
 
       // Handle both `"key", value` and `{key: value}` -style arguments.
+      var attrs;
       if (typeof key === 'object') {
         attrs = key;
         options = val;
@@ -323,37 +478,40 @@
       if (!this._validate(attrs, options)) return false;
 
       // Extract attributes and options.
-      unset           = options.unset;
-      silent          = options.silent;
-      changes         = [];
-      changing        = this._changing;
-      this._changing  = true;
+      var unset      = options.unset;
+      var silent     = options.silent;
+      var changes    = [];
+      var changing   = this._changing;
+      this._changing = true;
 
       if (!changing) {
         this._previousAttributes = _.clone(this.attributes);
         this.changed = {};
       }
-      current = this.attributes, prev = this._previousAttributes;
 
-      // Check for changes of `id`.
-      if (this.idAttribute in attrs) this.id = attrs[this.idAttribute];
+      var current = this.attributes;
+      var changed = this.changed;
+      var prev    = this._previousAttributes;
 
       // For each `set` attribute, update or delete the current value.
-      for (attr in attrs) {
+      for (var attr in attrs) {
         val = attrs[attr];
         if (!_.isEqual(current[attr], val)) changes.push(attr);
         if (!_.isEqual(prev[attr], val)) {
-          this.changed[attr] = val;
+          changed[attr] = val;
         } else {
-          delete this.changed[attr];
+          delete changed[attr];
         }
         unset ? delete current[attr] : current[attr] = val;
       }
 
+      // Update the `id`.
+      this.id = this.get(this.idAttribute);
+
       // Trigger all relevant attribute changes.
       if (!silent) {
         if (changes.length) this._pending = options;
-        for (var i = 0, l = changes.length; i < l; i++) {
+        for (var i = 0; i < changes.length; i++) {
           this.trigger('change:' + changes[i], this, current[changes[i]], options);
         }
       }
@@ -401,13 +559,14 @@
     // determining if there *would be* a change.
     changedAttributes: function(diff) {
       if (!diff) return this.hasChanged() ? _.clone(this.changed) : false;
-      var val, changed = false;
       var old = this._changing ? this._previousAttributes : this.attributes;
+      var changed = {};
       for (var attr in diff) {
-        if (_.isEqual(old[attr], (val = diff[attr]))) continue;
-        (changed || (changed = {}))[attr] = val;
+        var val = diff[attr];
+        if (_.isEqual(old[attr], val)) continue;
+        changed[attr] = val;
       }
-      return changed;
+      return _.size(changed) ? changed : false;
     },
 
     // Get the previous value of an attribute, recorded at the time the last
@@ -423,17 +582,16 @@
       return _.clone(this._previousAttributes);
     },
 
-    // Fetch the model from the server. If the server's representation of the
-    // model differs from its current attributes, they will be overridden,
-    // triggering a `"change"` event.
+    // Fetch the model from the server, merging the response with the model's
+    // local attributes. Any changed attributes will trigger a "change" event.
     fetch: function(options) {
-      options = options ? _.clone(options) : {};
-      if (options.parse === void 0) options.parse = true;
+      options = _.extend({parse: true}, options);
       var model = this;
       var success = options.success;
       options.success = function(resp) {
-        if (!model.set(model.parse(resp, options), options)) return false;
-        if (success) success(model, resp, options);
+        var serverAttrs = options.parse ? model.parse(resp, options) : resp;
+        if (!model.set(serverAttrs, options)) return false;
+        if (success) success.call(options.context, model, resp, options);
         model.trigger('sync', model, resp, options);
       };
       wrapError(this, options);
@@ -444,9 +602,8 @@
     // If the server returns an attributes hash that differs, the model's
     // state will be `set` again.
     save: function(key, val, options) {
-      var attrs, method, xhr, attributes = this.attributes;
-
       // Handle both `"key", value` and `{key: value}` -style arguments.
+      var attrs;
       if (key == null || typeof key === 'object') {
         attrs = key;
         options = val;
@@ -454,46 +611,43 @@
         (attrs = {})[key] = val;
       }
 
-      options = _.extend({validate: true}, options);
+      options = _.extend({validate: true, parse: true}, options);
+      var wait = options.wait;
 
       // If we're not waiting and attributes exist, save acts as
       // `set(attr).save(null, opts)` with validation. Otherwise, check if
       // the model will be valid when the attributes, if any, are set.
-      if (attrs && !options.wait) {
+      if (attrs && !wait) {
         if (!this.set(attrs, options)) return false;
       } else {
         if (!this._validate(attrs, options)) return false;
       }
 
-      // Set temporary attributes if `{wait: true}`.
-      if (attrs && options.wait) {
-        this.attributes = _.extend({}, attributes, attrs);
-      }
-
       // After a successful server-side save, the client is (optionally)
       // updated with the server-side state.
-      if (options.parse === void 0) options.parse = true;
       var model = this;
       var success = options.success;
+      var attributes = this.attributes;
       options.success = function(resp) {
         // Ensure attributes are restored during synchronous saves.
         model.attributes = attributes;
-        var serverAttrs = model.parse(resp, options);
-        if (options.wait) serverAttrs = _.extend(attrs || {}, serverAttrs);
-        if (_.isObject(serverAttrs) && !model.set(serverAttrs, options)) {
-          return false;
-        }
-        if (success) success(model, resp, options);
+        var serverAttrs = options.parse ? model.parse(resp, options) : resp;
+        if (wait) serverAttrs = _.extend({}, attrs, serverAttrs);
+        if (serverAttrs && !model.set(serverAttrs, options)) return false;
+        if (success) success.call(options.context, model, resp, options);
         model.trigger('sync', model, resp, options);
       };
       wrapError(this, options);
 
-      method = this.isNew() ? 'create' : (options.patch ? 'patch' : 'update');
-      if (method === 'patch') options.attrs = attrs;
-      xhr = this.sync(method, this, options);
+      // Set temporary attributes if `{wait: true}` to properly find new ids.
+      if (attrs && wait) this.attributes = _.extend({}, attributes, attrs);
+
+      var method = this.isNew() ? 'create' : (options.patch ? 'patch' : 'update');
+      if (method === 'patch' && !options.attrs) options.attrs = attrs;
+      var xhr = this.sync(method, this, options);
 
       // Restore attributes.
-      if (attrs && options.wait) this.attributes = attributes;
+      this.attributes = attributes;
 
       return xhr;
     },
@@ -505,25 +659,27 @@
       options = options ? _.clone(options) : {};
       var model = this;
       var success = options.success;
+      var wait = options.wait;
 
       var destroy = function() {
+        model.stopListening();
         model.trigger('destroy', model, model.collection, options);
       };
 
       options.success = function(resp) {
-        if (options.wait || model.isNew()) destroy();
-        if (success) success(model, resp, options);
+        if (wait) destroy();
+        if (success) success.call(options.context, model, resp, options);
         if (!model.isNew()) model.trigger('sync', model, resp, options);
       };
 
+      var xhr = false;
       if (this.isNew()) {
-        options.success();
-        return false;
+        _.defer(options.success);
+      } else {
+        wrapError(this, options);
+        xhr = this.sync('delete', this, options);
       }
-      wrapError(this, options);
-
-      var xhr = this.sync('delete', this, options);
-      if (!options.wait) destroy();
+      if (!wait) destroy();
       return xhr;
     },
 
@@ -536,7 +692,8 @@
         _.result(this.collection, 'url') ||
         urlError();
       if (this.isNew()) return base;
-      return base.replace(/([^\/])$/, '$1/') + encodeURIComponent(this.id);
+      var id = this.get(this.idAttribute);
+      return base.replace(/[^\/]$/, '$&/') + encodeURIComponent(id);
     },
 
     // **parse** converts a response into the hash of attributes to be `set` on
@@ -557,7 +714,7 @@
 
     // Check if the model is currently in a valid state.
     isValid: function(options) {
-      return this._validate({}, _.extend(options || {}, { validate: true }));
+      return this._validate({}, _.defaults({validate: true}, options));
     },
 
     // Run validation against the next complete set of model attributes,
@@ -573,23 +730,19 @@
 
   });
 
-  // Underscore methods that we want to implement on the Model.
-  var modelMethods = ['keys', 'values', 'pairs', 'invert', 'pick', 'omit'];
+  // Underscore methods that we want to implement on the Model, mapped to the
+  // number of arguments they take.
+  var modelMethods = { keys: 1, values: 1, pairs: 1, invert: 1, pick: 0,
+      omit: 0, chain: 1, isEmpty: 1 };
 
   // Mix in each Underscore method as a proxy to `Model#attributes`.
-  _.each(modelMethods, function(method) {
-    Model.prototype[method] = function() {
-      var args = slice.call(arguments);
-      args.unshift(this.attributes);
-      return _[method].apply(_, args);
-    };
-  });
+  addUnderscoreMethods(Model, modelMethods, 'attributes');
 
   // Backbone.Collection
   // -------------------
 
   // If models tend to represent a single row of data, a Backbone Collection is
-  // more analagous to a table full of data ... or a small slice or page of that
+  // more analogous to a table full of data ... or a small slice or page of that
   // table, or a collection of rows that belong together for a particular reason
   // -- all of the messages in this particular folder, all of the documents
   // belonging to this particular author, and so on. Collections maintain
@@ -611,6 +764,16 @@
   var setOptions = {add: true, remove: true, merge: true};
   var addOptions = {add: true, remove: false};
 
+  // Splices `insert` into `array` at index `at`.
+  var splice = function(array, insert, at) {
+    at = Math.min(Math.max(at, 0), array.length);
+    var tail = Array(array.length - at);
+    var length = insert.length;
+    for (var i = 0; i < tail.length; i++) tail[i] = array[i + at];
+    for (i = 0; i < length; i++) array[i + at] = insert[i];
+    for (i = 0; i < tail.length; i++) array[i + length + at] = tail[i];
+  };
+
   // Define the Collection's inheritable methods.
   _.extend(Collection.prototype, Events, {
 
@@ -625,7 +788,7 @@
     // The JSON representation of a Collection is an array of the
     // models' attributes.
     toJSON: function(options) {
-      return this.map(function(model){ return model.toJSON(options); });
+      return this.map(function(model) { return model.toJSON(options); });
     },
 
     // Proxy `Backbone.sync` by default.
@@ -633,32 +796,21 @@
       return Backbone.sync.apply(this, arguments);
     },
 
-    // Add a model, or list of models to the set.
+    // Add a model, or list of models to the set. `models` may be Backbone
+    // Models or raw JavaScript objects to be converted to Models, or any
+    // combination of the two.
     add: function(models, options) {
       return this.set(models, _.extend({merge: false}, options, addOptions));
     },
 
     // Remove a model, or a list of models from the set.
     remove: function(models, options) {
+      options = _.extend({}, options);
       var singular = !_.isArray(models);
       models = singular ? [models] : _.clone(models);
-      options || (options = {});
-      var i, l, index, model;
-      for (i = 0, l = models.length; i < l; i++) {
-        model = models[i] = this.get(models[i]);
-        if (!model) continue;
-        delete this._byId[model.id];
-        delete this._byId[model.cid];
-        index = this.indexOf(model);
-        this.models.splice(index, 1);
-        this.length--;
-        if (!options.silent) {
-          options.index = index;
-          model.trigger('remove', model, this, options);
-        }
-        this._removeReference(model, options);
-      }
-      return singular ? models[0] : models;
+      var removed = this._removeModels(models, options);
+      if (!options.silent && removed) this.trigger('update', this, options);
+      return singular ? removed[0] : removed;
     },
 
     // Update a collection by `set`-ing a new list of models, adding new ones,
@@ -666,78 +818,88 @@
     // already exist in the collection, as necessary. Similar to **Model#set**,
     // the core operation for updating the data contained by the collection.
     set: function(models, options) {
+      if (models == null) return;
+
       options = _.defaults({}, options, setOptions);
-      if (options.parse) models = this.parse(models, options);
+      if (options.parse && !this._isModel(models)) models = this.parse(models, options);
+
       var singular = !_.isArray(models);
-      models = singular ? (models ? [models] : []) : _.clone(models);
-      var i, l, id, model, attrs, existing, sort;
+      models = singular ? [models] : models.slice();
+
       var at = options.at;
-      var targetModel = this.model;
+      if (at != null) at = +at;
+      if (at < 0) at += this.length + 1;
+
+      var set = [];
+      var toAdd = [];
+      var toRemove = [];
+      var modelMap = {};
+
+      var add = options.add;
+      var merge = options.merge;
+      var remove = options.remove;
+
+      var sort = false;
       var sortable = this.comparator && (at == null) && options.sort !== false;
       var sortAttr = _.isString(this.comparator) ? this.comparator : null;
-      var toAdd = [], toRemove = [], modelMap = {};
-      var add = options.add, merge = options.merge, remove = options.remove;
-      var order = !sortable && add && remove ? [] : false;
 
       // Turn bare objects into model references, and prevent invalid models
       // from being added.
-      for (i = 0, l = models.length; i < l; i++) {
-        attrs = models[i] || {};
-        if (attrs instanceof Model) {
-          id = model = attrs;
-        } else {
-          id = attrs[targetModel.prototype.idAttribute || 'id'];
-        }
+      var model;
+      for (var i = 0; i < models.length; i++) {
+        model = models[i];
 
         // If a duplicate is found, prevent it from being added and
         // optionally merge it into the existing model.
-        if (existing = this.get(id)) {
-          if (remove) modelMap[existing.cid] = true;
-          if (merge) {
-            attrs = attrs === model ? model.attributes : attrs;
+        var existing = this.get(model);
+        if (existing) {
+          if (merge && model !== existing) {
+            var attrs = this._isModel(model) ? model.attributes : model;
             if (options.parse) attrs = existing.parse(attrs, options);
             existing.set(attrs, options);
-            if (sortable && !sort && existing.hasChanged(sortAttr)) sort = true;
+            if (sortable && !sort) sort = existing.hasChanged(sortAttr);
+          }
+          if (!modelMap[existing.cid]) {
+            modelMap[existing.cid] = true;
+            set.push(existing);
           }
           models[i] = existing;
 
         // If this is a new, valid model, push it to the `toAdd` list.
         } else if (add) {
-          model = models[i] = this._prepareModel(attrs, options);
-          if (!model) continue;
-          toAdd.push(model);
-          this._addReference(model, options);
+          model = models[i] = this._prepareModel(model, options);
+          if (model) {
+            toAdd.push(model);
+            this._addReference(model, options);
+            modelMap[model.cid] = true;
+            set.push(model);
+          }
         }
-
-        // Do not add multiple models with the same `id`.
-        model = existing || model;
-        if (order && (model.isNew() || !modelMap[model.id])) order.push(model);
-        modelMap[model.id] = true;
       }
 
-      // Remove nonexistent models if appropriate.
+      // Remove stale models.
       if (remove) {
-        for (i = 0, l = this.length; i < l; ++i) {
-          if (!modelMap[(model = this.models[i]).cid]) toRemove.push(model);
+        for (i = 0; i < this.length; i++) {
+          model = this.models[i];
+          if (!modelMap[model.cid]) toRemove.push(model);
         }
-        if (toRemove.length) this.remove(toRemove, options);
+        if (toRemove.length) this._removeModels(toRemove, options);
       }
 
       // See if sorting is needed, update `length` and splice in new models.
-      if (toAdd.length || (order && order.length)) {
+      var orderChanged = false;
+      var replace = !sortable && add && remove;
+      if (set.length && replace) {
+        orderChanged = this.length != set.length || _.some(this.models, function(model, index) {
+          return model !== set[index];
+        });
+        this.models.length = 0;
+        splice(this.models, set, 0);
+        this.length = this.models.length;
+      } else if (toAdd.length) {
         if (sortable) sort = true;
-        this.length += toAdd.length;
-        if (at != null) {
-          for (i = 0, l = toAdd.length; i < l; i++) {
-            this.models.splice(at + i, 0, toAdd[i]);
-          }
-        } else {
-          if (order) this.models.length = 0;
-          var orderedModels = order || toAdd;
-          for (i = 0, l = orderedModels.length; i < l; i++) {
-            this.models.push(orderedModels[i]);
-          }
-        }
+        splice(this.models, toAdd, at == null ? this.length : at);
+        this.length = this.models.length;
       }
 
       // Silently sort the collection if appropriate.
@@ -745,10 +907,13 @@
 
       // Unless silenced, it's time to fire all appropriate add/sort events.
       if (!options.silent) {
-        for (i = 0, l = toAdd.length; i < l; i++) {
-          (model = toAdd[i]).trigger('add', model, this, options);
+        for (i = 0; i < toAdd.length; i++) {
+          if (at != null) options.index = at + i;
+          model = toAdd[i];
+          model.trigger('add', model, this, options);
         }
-        if (sort || (order && order.length)) this.trigger('sort', this, options);
+        if (sort || orderChanged) this.trigger('sort', this, options);
+        if (toAdd.length || toRemove.length) this.trigger('update', this, options);
       }
 
       // Return the added (or merged) model (or models).
@@ -760,8 +925,8 @@
     // any granular `add` or `remove` events. Fires `reset` when finished.
     // Useful for bulk operations and optimizations.
     reset: function(models, options) {
-      options || (options = {});
-      for (var i = 0, l = this.models.length; i < l; i++) {
+      options = options ? _.clone(options) : {};
+      for (var i = 0; i < this.models.length; i++) {
         this._removeReference(this.models[i], options);
       }
       options.previousModels = this.models;
@@ -779,8 +944,7 @@
     // Remove a model from the end of the collection.
     pop: function(options) {
       var model = this.at(this.length - 1);
-      this.remove(model, options);
-      return model;
+      return this.remove(model, options);
     },
 
     // Add a model to the beginning of the collection.
@@ -791,8 +955,7 @@
     // Remove a model from the beginning of the collection.
     shift: function(options) {
       var model = this.at(0);
-      this.remove(model, options);
-      return model;
+      return this.remove(model, options);
     },
 
     // Slice out a sub-array of models from the collection.
@@ -803,24 +966,20 @@
     // Get a model from the set by id.
     get: function(obj) {
       if (obj == null) return void 0;
-      return this._byId[obj] || this._byId[obj.id] || this._byId[obj.cid];
+      var id = this.modelId(this._isModel(obj) ? obj.attributes : obj);
+      return this._byId[obj] || this._byId[id] || this._byId[obj.cid];
     },
 
     // Get the model at the given index.
     at: function(index) {
+      if (index < 0) index += this.length;
       return this.models[index];
     },
 
     // Return models with matching attributes. Useful for simple cases of
     // `filter`.
     where: function(attrs, first) {
-      if (_.isEmpty(attrs)) return first ? void 0 : [];
-      return this[first ? 'find' : 'filter'](function(model) {
-        for (var key in attrs) {
-          if (attrs[key] !== model.get(key)) return false;
-        }
-        return true;
-      });
+      return this[first ? 'find' : 'filter'](attrs);
     },
 
     // Return the first model with matching attributes. Useful for simple cases
@@ -833,16 +992,19 @@
     // normal circumstances, as the set will maintain sort order as each item
     // is added.
     sort: function(options) {
-      if (!this.comparator) throw new Error('Cannot sort a set without a comparator');
+      var comparator = this.comparator;
+      if (!comparator) throw new Error('Cannot sort a set without a comparator');
       options || (options = {});
 
+      var length = comparator.length;
+      if (_.isFunction(comparator)) comparator = _.bind(comparator, this);
+
       // Run sort based on type of `comparator`.
-      if (_.isString(this.comparator) || this.comparator.length === 1) {
-        this.models = this.sortBy(this.comparator, this);
+      if (length === 1 || _.isString(comparator)) {
+        this.models = this.sortBy(comparator);
       } else {
-        this.models.sort(_.bind(this.comparator, this));
+        this.models.sort(comparator);
       }
-
       if (!options.silent) this.trigger('sort', this, options);
       return this;
     },
@@ -856,14 +1018,13 @@
     // collection when they arrive. If `reset: true` is passed, the response
     // data will be passed through the `reset` method instead of `set`.
     fetch: function(options) {
-      options = options ? _.clone(options) : {};
-      if (options.parse === void 0) options.parse = true;
+      options = _.extend({parse: true}, options);
       var success = options.success;
       var collection = this;
       options.success = function(resp) {
         var method = options.reset ? 'reset' : 'set';
         collection[method](resp, options);
-        if (success) success(collection, resp, options);
+        if (success) success.call(options.context, collection, resp, options);
         collection.trigger('sync', collection, resp, options);
       };
       wrapError(this, options);
@@ -875,13 +1036,15 @@
     // wait for the server to agree.
     create: function(model, options) {
       options = options ? _.clone(options) : {};
-      if (!(model = this._prepareModel(model, options))) return false;
-      if (!options.wait) this.add(model, options);
+      var wait = options.wait;
+      model = this._prepareModel(model, options);
+      if (!model) return false;
+      if (!wait) this.add(model, options);
       var collection = this;
       var success = options.success;
-      options.success = function(model, resp) {
-        if (options.wait) collection.add(model, options);
-        if (success) success(model, resp, options);
+      options.success = function(model, resp, callbackOpts) {
+        if (wait) collection.add(model, callbackOpts);
+        if (success) success.call(callbackOpts.context, model, resp, callbackOpts);
       };
       model.save(null, options);
       return model;
@@ -895,7 +1058,15 @@
 
     // Create a new collection with an identical list of models as this one.
     clone: function() {
-      return new this.constructor(this.models);
+      return new this.constructor(this.models, {
+        model: this.model,
+        comparator: this.comparator
+      });
+    },
+
+    // Define how to uniquely identify models in the collection.
+    modelId: function (attrs) {
+      return attrs[this.model.prototype.idAttribute || 'id'];
     },
 
     // Private method to reset all internal state. Called when the collection
@@ -909,7 +1080,10 @@
     // Prepare a hash of attributes (or other model) to be added to this
     // collection.
     _prepareModel: function(attrs, options) {
-      if (attrs instanceof Model) return attrs;
+      if (this._isModel(attrs)) {
+        if (!attrs.collection) attrs.collection = this;
+        return attrs;
+      }
       options = options ? _.clone(options) : {};
       options.collection = this;
       var model = new this.model(attrs, options);
@@ -918,16 +1092,47 @@
       return false;
     },
 
+    // Internal method called by both remove and set.
+    _removeModels: function(models, options) {
+      var removed = [];
+      for (var i = 0; i < models.length; i++) {
+        var model = this.get(models[i]);
+        if (!model) continue;
+
+        var index = this.indexOf(model);
+        this.models.splice(index, 1);
+        this.length--;
+
+        if (!options.silent) {
+          options.index = index;
+          model.trigger('remove', model, this, options);
+        }
+
+        removed.push(model);
+        this._removeReference(model, options);
+      }
+      return removed.length ? removed : false;
+    },
+
+    // Method for checking whether an object should be considered a model for
+    // the purposes of adding to the collection.
+    _isModel: function (model) {
+      return model instanceof Model;
+    },
+
     // Internal method to create a model's ties to a collection.
     _addReference: function(model, options) {
       this._byId[model.cid] = model;
-      if (model.id != null) this._byId[model.id] = model;
-      if (!model.collection) model.collection = this;
+      var id = this.modelId(model.attributes);
+      if (id != null) this._byId[id] = model;
       model.on('all', this._onModelEvent, this);
     },
 
     // Internal method to sever a model's ties to a collection.
     _removeReference: function(model, options) {
+      delete this._byId[model.cid];
+      var id = this.modelId(model.attributes);
+      if (id != null) delete this._byId[id];
       if (this === model.collection) delete model.collection;
       model.off('all', this._onModelEvent, this);
     },
@@ -939,9 +1144,13 @@
     _onModelEvent: function(event, model, collection, options) {
       if ((event === 'add' || event === 'remove') && collection !== this) return;
       if (event === 'destroy') this.remove(model, options);
-      if (model && event === 'change:' + model.idAttribute) {
-        delete this._byId[model.previous(model.idAttribute)];
-        if (model.id != null) this._byId[model.id] = model;
+      if (event === 'change') {
+        var prevId = this.modelId(model.previousAttributes());
+        var id = this.modelId(model.attributes);
+        if (prevId !== id) {
+          if (prevId != null) delete this._byId[prevId];
+          if (id != null) this._byId[id] = model;
+        }
       }
       this.trigger.apply(this, arguments);
     }
@@ -951,34 +1160,17 @@
   // Underscore methods that we want to implement on the Collection.
   // 90% of the core usefulness of Backbone Collections is actually implemented
   // right here:
-  var methods = ['forEach', 'each', 'map', 'collect', 'reduce', 'foldl',
-    'inject', 'reduceRight', 'foldr', 'find', 'detect', 'filter', 'select',
-    'reject', 'every', 'all', 'some', 'any', 'include', 'contains', 'invoke',
-    'max', 'min', 'toArray', 'size', 'first', 'head', 'take', 'initial', 'rest',
-    'tail', 'drop', 'last', 'without', 'difference', 'indexOf', 'shuffle',
-    'lastIndexOf', 'isEmpty', 'chain', 'sample'];
+  var collectionMethods = { forEach: 3, each: 3, map: 3, collect: 3, reduce: 4,
+      foldl: 4, inject: 4, reduceRight: 4, foldr: 4, find: 3, detect: 3, filter: 3,
+      select: 3, reject: 3, every: 3, all: 3, some: 3, any: 3, include: 3, includes: 3,
+      contains: 3, invoke: 0, max: 3, min: 3, toArray: 1, size: 1, first: 3,
+      head: 3, take: 3, initial: 3, rest: 3, tail: 3, drop: 3, last: 3,
+      without: 0, difference: 0, indexOf: 3, shuffle: 1, lastIndexOf: 3,
+      isEmpty: 1, chain: 1, sample: 3, partition: 3, groupBy: 3, countBy: 3,
+      sortBy: 3, indexBy: 3};
 
   // Mix in each Underscore method as a proxy to `Collection#models`.
-  _.each(methods, function(method) {
-    Collection.prototype[method] = function() {
-      var args = slice.call(arguments);
-      args.unshift(this.models);
-      return _[method].apply(_, args);
-    };
-  });
-
-  // Underscore methods that take a property name as an argument.
-  var attributeMethods = ['groupBy', 'countBy', 'sortBy', 'indexBy'];
-
-  // Use attributes instead of properties.
-  _.each(attributeMethods, function(method) {
-    Collection.prototype[method] = function(value, context) {
-      var iterator = _.isFunction(value) ? value : function(model) {
-        return model.get(value);
-      };
-      return _[method](this.models, iterator, context);
-    };
-  });
+  addUnderscoreMethods(Collection, collectionMethods, 'models');
 
   // Backbone.View
   // -------------
@@ -995,17 +1187,15 @@
   // if an existing element is not provided...
   var View = Backbone.View = function(options) {
     this.cid = _.uniqueId('view');
-    options || (options = {});
     _.extend(this, _.pick(options, viewOptions));
     this._ensureElement();
     this.initialize.apply(this, arguments);
-    this.delegateEvents();
   };
 
   // Cached regex to split keys for `delegate`.
   var delegateEventSplitter = /^(\S+)\s*(.*)$/;
 
-  // List of view options to be merged as properties.
+  // List of view options to be set as properties.
   var viewOptions = ['model', 'collection', 'el', 'id', 'attributes', 'className', 'tagName', 'events'];
 
   // Set up all inheritable **Backbone.View** properties and methods.
@@ -1034,19 +1224,35 @@
     // Remove this view by taking the element out of the DOM, and removing any
     // applicable Backbone.Events listeners.
     remove: function() {
-      this.$el.remove();
+      this._removeElement();
       this.stopListening();
       return this;
     },
 
-    // Change the view's element (`this.el` property), including event
-    // re-delegation.
-    setElement: function(element, delegate) {
-      if (this.$el) this.undelegateEvents();
-      this.$el = element instanceof Backbone.$ ? element : Backbone.$(element);
+    // Remove this view's element from the document and all event listeners
+    // attached to it. Exposed for subclasses using an alternative DOM
+    // manipulation API.
+    _removeElement: function() {
+      this.$el.remove();
+    },
+
+    // Change the view's element (`this.el` property) and re-delegate the
+    // view's events on the new element.
+    setElement: function(element) {
+      this.undelegateEvents();
+      this._setElement(element);
+      this.delegateEvents();
+      return this;
+    },
+
+    // Creates the `this.el` and `this.$el` references for this view using the
+    // given `el`. `el` can be a CSS selector or an HTML string, a jQuery
+    // context or an element. Subclasses can override this to utilize an
+    // alternative DOM manipulation API and are only required to set the
+    // `this.el` property.
+    _setElement: function(el) {
+      this.$el = el instanceof Backbone.$ ? el : Backbone.$(el);
       this.el = this.$el[0];
-      if (delegate !== false) this.delegateEvents();
-      return this;
     },
 
     // Set callbacks, where `this.events` is a hash of
@@ -1062,37 +1268,49 @@
     // pairs. Callbacks will be bound to the view, with `this` set properly.
     // Uses event delegation for efficiency.
     // Omitting the selector binds the event to `this.el`.
-    // This only works for delegate-able events: not `focus`, `blur`, and
-    // not `change`, `submit`, and `reset` in Internet Explorer.
     delegateEvents: function(events) {
-      if (!(events || (events = _.result(this, 'events')))) return this;
+      events || (events = _.result(this, 'events'));
+      if (!events) return this;
       this.undelegateEvents();
       for (var key in events) {
         var method = events[key];
-        if (!_.isFunction(method)) method = this[events[key]];
+        if (!_.isFunction(method)) method = this[method];
         if (!method) continue;
-
         var match = key.match(delegateEventSplitter);
-        var eventName = match[1], selector = match[2];
-        method = _.bind(method, this);
-        eventName += '.delegateEvents' + this.cid;
-        if (selector === '') {
-          this.$el.on(eventName, method);
-        } else {
-          this.$el.on(eventName, selector, method);
-        }
+        this.delegate(match[1], match[2], _.bind(method, this));
       }
       return this;
     },
 
-    // Clears all callbacks previously bound to the view with `delegateEvents`.
+    // Add a single event listener to the view's element (or a child element
+    // using `selector`). This only works for delegate-able events: not `focus`,
+    // `blur`, and not `change`, `submit`, and `reset` in Internet Explorer.
+    delegate: function(eventName, selector, listener) {
+      this.$el.on(eventName + '.delegateEvents' + this.cid, selector, listener);
+      return this;
+    },
+
+    // Clears all callbacks previously bound to the view by `delegateEvents`.
     // You usually don't need to use this, but may wish to if you have multiple
     // Backbone views attached to the same DOM element.
     undelegateEvents: function() {
-      this.$el.off('.delegateEvents' + this.cid);
+      if (this.$el) this.$el.off('.delegateEvents' + this.cid);
       return this;
     },
 
+    // A finer-grained `undelegateEvents` for removing a single delegated event.
+    // `selector` and `listener` are both optional.
+    undelegate: function(eventName, selector, listener) {
+      this.$el.off(eventName + '.delegateEvents' + this.cid, selector, listener);
+      return this;
+    },
+
+    // Produces a DOM element to be assigned to your view. Exposed for
+    // subclasses using an alternative DOM manipulation API.
+    _createElement: function(tagName) {
+      return document.createElement(tagName);
+    },
+
     // Ensure that the View has a DOM element to render into.
     // If `this.el` is a string, pass it through `$()`, take the first
     // matching element, and re-assign it to `el`. Otherwise, create
@@ -1102,11 +1320,17 @@
         var attrs = _.extend({}, _.result(this, 'attributes'));
         if (this.id) attrs.id = _.result(this, 'id');
         if (this.className) attrs['class'] = _.result(this, 'className');
-        var $el = Backbone.$('<' + _.result(this, 'tagName') + '>').attr(attrs);
-        this.setElement($el, false);
+        this.setElement(this._createElement(_.result(this, 'tagName')));
+        this._setAttributes(attrs);
       } else {
-        this.setElement(_.result(this, 'el'), false);
+        this.setElement(_.result(this, 'el'));
       }
+    },
+
+    // Set attributes from a hash on this view's element.  Exposed for
+    // subclasses using an alternative DOM manipulation API.
+    _setAttributes: function(attributes) {
+      this.$el.attr(attributes);
     }
 
   });
@@ -1175,14 +1399,13 @@
       params.processData = false;
     }
 
-    // If we're sending a `PATCH` request, and we're in an old Internet Explorer
-    // that still has ActiveX enabled by default, override jQuery to use that
-    // for XHR instead. Remove this line when jQuery supports `PATCH` on IE8.
-    if (params.type === 'PATCH' && noXhrPatch) {
-      params.xhr = function() {
-        return new ActiveXObject("Microsoft.XMLHTTP");
-      };
-    }
+    // Pass along `textStatus` and `errorThrown` from jQuery.
+    var error = options.error;
+    options.error = function(xhr, textStatus, errorThrown) {
+      options.textStatus = textStatus;
+      options.errorThrown = errorThrown;
+      if (error) error.call(options.context, xhr, textStatus, errorThrown);
+    };
 
     // Make the request, allowing the user to override any Ajax options.
     var xhr = options.xhr = Backbone.ajax(_.extend(params, options));
@@ -1190,10 +1413,6 @@
     return xhr;
   };
 
-  var noXhrPatch =
-    typeof window !== 'undefined' && !!window.ActiveXObject &&
-      !(window.XMLHttpRequest && (new XMLHttpRequest).dispatchEvent);
-
   // Map from CRUD to HTTP for our default `Backbone.sync` implementation.
   var methodMap = {
     'create': 'POST',
@@ -1251,17 +1470,18 @@
       var router = this;
       Backbone.history.route(route, function(fragment) {
         var args = router._extractParameters(route, fragment);
-        router.execute(callback, args);
-        router.trigger.apply(router, ['route:' + name].concat(args));
-        router.trigger('route', name, args);
-        Backbone.history.trigger('route', router, name, args);
+        if (router.execute(callback, args, name) !== false) {
+          router.trigger.apply(router, ['route:' + name].concat(args));
+          router.trigger('route', name, args);
+          Backbone.history.trigger('route', router, name, args);
+        }
       });
       return this;
     },
 
     // Execute a route handler with the provided parameters.  This is an
     // excellent place to do pre-route setup or post-route cleanup.
-    execute: function(callback, args) {
+    execute: function(callback, args, name) {
       if (callback) callback.apply(this, args);
     },
 
@@ -1319,7 +1539,7 @@
   // falls back to polling.
   var History = Backbone.History = function() {
     this.handlers = [];
-    _.bindAll(this, 'checkUrl');
+    this.checkUrl = _.bind(this.checkUrl, this);
 
     // Ensure that `History` can be used outside of the browser.
     if (typeof window !== 'undefined') {
@@ -1334,12 +1554,6 @@
   // Cached regex for stripping leading and trailing slashes.
   var rootStripper = /^\/+|\/+$/g;
 
-  // Cached regex for detecting MSIE.
-  var isExplorer = /msie [\w.]+/;
-
-  // Cached regex for removing a trailing slash.
-  var trailingSlash = /\/$/;
-
   // Cached regex for stripping urls of hash.
   var pathStripper = /#.*$/;
 
@@ -1355,7 +1569,29 @@
 
     // Are we at the app root?
     atRoot: function() {
-      return this.location.pathname.replace(/[^\/]$/, '$&/') === this.root;
+      var path = this.location.pathname.replace(/[^\/]$/, '$&/');
+      return path === this.root && !this.getSearch();
+    },
+
+    // Does the pathname match the root?
+    matchRoot: function() {
+      var path = this.decodeFragment(this.location.pathname);
+      var root = path.slice(0, this.root.length - 1) + '/';
+      return root === this.root;
+    },
+
+    // Unicode characters in `location.pathname` are percent encoded so they're
+    // decoded for comparison. `%25` should not be decoded since it may be part
+    // of an encoded parameter.
+    decodeFragment: function(fragment) {
+      return decodeURI(fragment.replace(/%25/g, '%2525'));
+    },
+
+    // In IE6, the hash fragment and search params are incorrect if the
+    // fragment contains `?`.
+    getSearch: function() {
+      var match = this.location.href.replace(/#.*/, '').match(/\?.+/);
+      return match ? match[0] : '';
     },
 
     // Gets the true hash value. Cannot use location.hash directly due to bug
@@ -1365,14 +1601,19 @@
       return match ? match[1] : '';
     },
 
-    // Get the cross-browser normalized URL fragment, either from the URL,
-    // the hash, or the override.
-    getFragment: function(fragment, forcePushState) {
+    // Get the pathname and search params, without the root.
+    getPath: function() {
+      var path = this.decodeFragment(
+        this.location.pathname + this.getSearch()
+      ).slice(this.root.length - 1);
+      return path.charAt(0) === '/' ? path.slice(1) : path;
+    },
+
+    // Get the cross-browser normalized URL fragment from the path or hash.
+    getFragment: function(fragment) {
       if (fragment == null) {
-        if (this._hasPushState || !this._wantsHashChange || forcePushState) {
-          fragment = decodeURI(this.location.pathname + this.location.search);
-          var root = this.root.replace(trailingSlash, '');
-          if (!fragment.indexOf(root)) fragment = fragment.slice(root.length);
+        if (this._usePushState || !this._wantsHashChange) {
+          fragment = this.getPath();
         } else {
           fragment = this.getHash();
         }
@@ -1383,7 +1624,7 @@
     // Start the hash change handling, returning `true` if the current URL matches
     // an existing route, and `false` otherwise.
     start: function(options) {
-      if (History.started) throw new Error("Backbone.history has already been started");
+      if (History.started) throw new Error('Backbone.history has already been started');
       History.started = true;
 
       // Figure out the initial configuration. Do we need an iframe?
@@ -1391,36 +1632,16 @@
       this.options          = _.extend({root: '/'}, this.options, options);
       this.root             = this.options.root;
       this._wantsHashChange = this.options.hashChange !== false;
+      this._hasHashChange   = 'onhashchange' in window && (document.documentMode === void 0 || document.documentMode > 7);
+      this._useHashChange   = this._wantsHashChange && this._hasHashChange;
       this._wantsPushState  = !!this.options.pushState;
-      this._hasPushState    = !!(this.options.pushState && this.history && this.history.pushState);
-      var fragment          = this.getFragment();
-      var docMode           = document.documentMode;
-      var oldIE             = (isExplorer.exec(navigator.userAgent.toLowerCase()) && (!docMode || docMode <= 7));
+      this._hasPushState    = !!(this.history && this.history.pushState);
+      this._usePushState    = this._wantsPushState && this._hasPushState;
+      this.fragment         = this.getFragment();
 
       // Normalize root to always include a leading and trailing slash.
       this.root = ('/' + this.root + '/').replace(rootStripper, '/');
 
-      if (oldIE && this._wantsHashChange) {
-        var frame = Backbone.$('<iframe src="javascript:0" tabindex="-1">');
-        this.iframe = frame.hide().appendTo('body')[0].contentWindow;
-        this.navigate(fragment);
-      }
-
-      // Depending on whether we're using pushState or hashes, and whether
-      // 'onhashchange' is supported, determine how we check the URL state.
-      if (this._hasPushState) {
-        Backbone.$(window).on('popstate', this.checkUrl);
-      } else if (this._wantsHashChange && ('onhashchange' in window) && !oldIE) {
-        Backbone.$(window).on('hashchange', this.checkUrl);
-      } else if (this._wantsHashChange) {
-        this._checkUrlInterval = setInterval(this.checkUrl, this.interval);
-      }
-
-      // Determine if we need to change the base url, for a pushState link
-      // opened by a non-pushState browser.
-      this.fragment = fragment;
-      var loc = this.location;
-
       // Transition from hashChange to pushState or vice versa if both are
       // requested.
       if (this._wantsHashChange && this._wantsPushState) {
@@ -1428,27 +1649,75 @@
         // If we've started off with a route from a `pushState`-enabled
         // browser, but we're currently in a browser that doesn't support it...
         if (!this._hasPushState && !this.atRoot()) {
-          this.fragment = this.getFragment(null, true);
-          this.location.replace(this.root + '#' + this.fragment);
+          var root = this.root.slice(0, -1) || '/';
+          this.location.replace(root + '#' + this.getPath());
           // Return immediately as browser will do redirect to new url
           return true;
 
         // Or if we've started out with a hash-based route, but we're currently
         // in a browser where it could be `pushState`-based instead...
-        } else if (this._hasPushState && this.atRoot() && loc.hash) {
-          this.fragment = this.getHash().replace(routeStripper, '');
-          this.history.replaceState({}, document.title, this.root + this.fragment);
+        } else if (this._hasPushState && this.atRoot()) {
+          this.navigate(this.getHash(), {replace: true});
         }
 
       }
 
+      // Proxy an iframe to handle location events if the browser doesn't
+      // support the `hashchange` event, HTML5 history, or the user wants
+      // `hashChange` but not `pushState`.
+      if (!this._hasHashChange && this._wantsHashChange && !this._usePushState) {
+        this.iframe = document.createElement('iframe');
+        this.iframe.src = 'javascript:0';
+        this.iframe.style.display = 'none';
+        this.iframe.tabIndex = -1;
+        var body = document.body;
+        // Using `appendChild` will throw on IE < 9 if the document is not ready.
+        var iWindow = body.insertBefore(this.iframe, body.firstChild).contentWindow;
+        iWindow.document.open();
+        iWindow.document.close();
+        iWindow.location.hash = '#' + this.fragment;
+      }
+
+      // Add a cross-platform `addEventListener` shim for older browsers.
+      var addEventListener = window.addEventListener || function (eventName, listener) {
+        return attachEvent('on' + eventName, listener);
+      };
+
+      // Depending on whether we're using pushState or hashes, and whether
+      // 'onhashchange' is supported, determine how we check the URL state.
+      if (this._usePushState) {
+        addEventListener('popstate', this.checkUrl, false);
+      } else if (this._useHashChange && !this.iframe) {
+        addEventListener('hashchange', this.checkUrl, false);
+      } else if (this._wantsHashChange) {
+        this._checkUrlInterval = setInterval(this.checkUrl, this.interval);
+      }
+
       if (!this.options.silent) return this.loadUrl();
     },
 
     // Disable Backbone.history, perhaps temporarily. Not useful in a real app,
     // but possibly useful for unit testing Routers.
     stop: function() {
-      Backbone.$(window).off('popstate', this.checkUrl).off('hashchange', this.checkUrl);
+      // Add a cross-platform `removeEventListener` shim for older browsers.
+      var removeEventListener = window.removeEventListener || function (eventName, listener) {
+        return detachEvent('on' + eventName, listener);
+      };
+
+      // Remove window listeners.
+      if (this._usePushState) {
+        removeEventListener('popstate', this.checkUrl, false);
+      } else if (this._useHashChange && !this.iframe) {
+        removeEventListener('hashchange', this.checkUrl, false);
+      }
+
+      // Clean up the iframe if necessary.
+      if (this.iframe) {
+        document.body.removeChild(this.iframe);
+        this.iframe = null;
+      }
+
+      // Some environments will throw when clearing an undefined interval.
       if (this._checkUrlInterval) clearInterval(this._checkUrlInterval);
       History.started = false;
     },
@@ -1463,9 +1732,13 @@
     // calls `loadUrl`, normalizing across the hidden iframe.
     checkUrl: function(e) {
       var current = this.getFragment();
+
+      // If the user pressed the back button, the iframe's hash will have
+      // changed and we should use that for comparison.
       if (current === this.fragment && this.iframe) {
-        current = this.getFragment(this.getHash(this.iframe));
+        current = this.getHash(this.iframe.contentWindow);
       }
+
       if (current === this.fragment) return false;
       if (this.iframe) this.navigate(current);
       this.loadUrl();
@@ -1475,8 +1748,10 @@
     // match, returns `true`. If no defined routes matches the fragment,
     // returns `false`.
     loadUrl: function(fragment) {
+      // If the root doesn't match, no routes can match either.
+      if (!this.matchRoot()) return false;
       fragment = this.fragment = this.getFragment(fragment);
-      return _.any(this.handlers, function(handler) {
+      return _.some(this.handlers, function(handler) {
         if (handler.route.test(fragment)) {
           handler.callback(fragment);
           return true;
@@ -1495,31 +1770,42 @@
       if (!History.started) return false;
       if (!options || options === true) options = {trigger: !!options};
 
-      var url = this.root + (fragment = this.getFragment(fragment || ''));
+      // Normalize the fragment.
+      fragment = this.getFragment(fragment || '');
 
-      // Strip the hash for matching.
-      fragment = fragment.replace(pathStripper, '');
+      // Don't include a trailing slash on the root.
+      var root = this.root;
+      if (fragment === '' || fragment.charAt(0) === '?') {
+        root = root.slice(0, -1) || '/';
+      }
+      var url = root + fragment;
+
+      // Strip the hash and decode for matching.
+      fragment = this.decodeFragment(fragment.replace(pathStripper, ''));
 
       if (this.fragment === fragment) return;
       this.fragment = fragment;
 
-      // Don't include a trailing slash on the root.
-      if (fragment === '' && url !== '/') url = url.slice(0, -1);
-
       // If pushState is available, we use it to set the fragment as a real URL.
-      if (this._hasPushState) {
+      if (this._usePushState) {
         this.history[options.replace ? 'replaceState' : 'pushState']({}, document.title, url);
 
       // If hash changes haven't been explicitly disabled, update the hash
       // fragment to store history.
       } else if (this._wantsHashChange) {
         this._updateHash(this.location, fragment, options.replace);
-        if (this.iframe && (fragment !== this.getFragment(this.getHash(this.iframe)))) {
+        if (this.iframe && (fragment !== this.getHash(this.iframe.contentWindow))) {
+          var iWindow = this.iframe.contentWindow;
+
           // Opening and closing the iframe tricks IE7 and earlier to push a
           // history entry on hash-tag change.  When replace is true, we don't
           // want this.
-          if(!options.replace) this.iframe.document.open().close();
-          this._updateHash(this.iframe.location, fragment, options.replace);
+          if (!options.replace) {
+            iWindow.document.open();
+            iWindow.document.close();
+          }
+
+          this._updateHash(iWindow.location, fragment, options.replace);
         }
 
       // If you've told us that you explicitly don't want fallback hashchange-
@@ -1550,7 +1836,7 @@
   // Helpers
   // -------
 
-  // Helper function to correctly set up the prototype chain, for subclasses.
+  // Helper function to correctly set up the prototype chain for subclasses.
   // Similar to `goog.inherits`, but uses a hash of prototype properties and
   // class properties to be extended.
   var extend = function(protoProps, staticProps) {
@@ -1559,7 +1845,7 @@
 
     // The constructor function for the new subclass is either defined by you
     // (the "constructor" property in your `extend` definition), or defaulted
-    // by us to simply call the parent's constructor.
+    // by us to simply call the parent constructor.
     if (protoProps && _.has(protoProps, 'constructor')) {
       child = protoProps.constructor;
     } else {
@@ -1570,7 +1856,7 @@
     _.extend(child, parent, staticProps);
 
     // Set the prototype chain to inherit from `parent`, without calling
-    // `parent`'s constructor function.
+    // `parent` constructor function.
     var Surrogate = function(){ this.constructor = child; };
     Surrogate.prototype = parent.prototype;
     child.prototype = new Surrogate;
@@ -1598,7 +1884,7 @@
   var wrapError = function(model, options) {
     var error = options.error;
     options.error = function(resp) {
-      if (error) error(model, resp, options);
+      if (error) error.call(options.context, model, resp, options);
       model.trigger('error', model, resp, options);
     };
   };
--- a/server/python/django/renkanmanager/static/renkanmanager/lib/lodash/lodash.js	Wed Sep 09 15:05:30 2015 +0200
+++ b/server/python/django/renkanmanager/static/renkanmanager/lib/lodash/lodash.js	Wed Sep 09 15:18:53 2015 +0200
@@ -1,175 +1,350 @@
 /**
  * @license
- * Lo-Dash 2.4.2 (Custom Build) <https://lodash.com/>
- * Build: `lodash modern -o ./dist/lodash.js`
- * Copyright 2012-2013 The Dojo Foundation <http://dojofoundation.org/>
- * Based on Underscore.js 1.5.2 <http://underscorejs.org/LICENSE>
- * Copyright 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
+ * lodash 3.10.1 (Custom Build) <https://lodash.com/>
+ * Build: `lodash modern -o ./lodash.js`
+ * Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
+ * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
+ * Copyright 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
  * Available under MIT license <https://lodash.com/license>
  */
 ;(function() {
 
-  /** Used as a safe reference for `undefined` in pre ES5 environments */
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   var undefined;
 
-  /** Used to pool arrays and objects used internally */
-  var arrayPool = [],
-      objectPool = [];
-
-  /** Used to generate unique IDs */
-  var idCounter = 0;
-
-  /** Used to prefix keys to avoid issues with `__proto__` and properties on `Object.prototype` */
-  var keyPrefix = +new Date + '';
-
-  /** Used as the size when optimizations are enabled for large arrays */
-  var largeArraySize = 75;
-
-  /** Used as the max size of the `arrayPool` and `objectPool` */
-  var maxPoolSize = 40;
-
-  /** Used to detect and test whitespace */
-  var whitespace = (
-    // whitespace
-    ' \t\x0B\f\xA0\ufeff' +
-
-    // line terminators
-    '\n\r\u2028\u2029' +
-
-    // unicode category "Zs" space separators
-    '\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000'
-  );
-
-  /** Used to match empty string literals in compiled template source */
+  /** Used as the semantic version number. */
+  var VERSION = '3.10.1';
+
+  /** Used to compose bitmasks for wrapper metadata. */
+  var BIND_FLAG = 1,
+      BIND_KEY_FLAG = 2,
+      CURRY_BOUND_FLAG = 4,
+      CURRY_FLAG = 8,
+      CURRY_RIGHT_FLAG = 16,
+      PARTIAL_FLAG = 32,
+      PARTIAL_RIGHT_FLAG = 64,
+      ARY_FLAG = 128,
+      REARG_FLAG = 256;
+
+  /** Used as default options for `_.trunc`. */
+  var DEFAULT_TRUNC_LENGTH = 30,
+      DEFAULT_TRUNC_OMISSION = '...';
+
+  /** Used to detect when a function becomes hot. */
+  var HOT_COUNT = 150,
+      HOT_SPAN = 16;
+
+  /** Used as the size to enable large array optimizations. */
+  var LARGE_ARRAY_SIZE = 200;
+
+  /** Used to indicate the type of lazy iteratees. */
+  var LAZY_FILTER_FLAG = 1,
+      LAZY_MAP_FLAG = 2;
+
+  /** Used as the `TypeError` message for "Functions" methods. */
+  var FUNC_ERROR_TEXT = 'Expected a function';
+
+  /** Used as the internal argument placeholder. */
+  var PLACEHOLDER = '__lodash_placeholder__';
+
+  /** `Object#toString` result references. */
+  var argsTag = '[object Arguments]',
+      arrayTag = '[object Array]',
+      boolTag = '[object Boolean]',
+      dateTag = '[object Date]',
+      errorTag = '[object Error]',
+      funcTag = '[object Function]',
+      mapTag = '[object Map]',
+      numberTag = '[object Number]',
+      objectTag = '[object Object]',
+      regexpTag = '[object RegExp]',
+      setTag = '[object Set]',
+      stringTag = '[object String]',
+      weakMapTag = '[object WeakMap]';
+
+  var arrayBufferTag = '[object ArrayBuffer]',
+      float32Tag = '[object Float32Array]',
+      float64Tag = '[object Float64Array]',
+      int8Tag = '[object Int8Array]',
+      int16Tag = '[object Int16Array]',
+      int32Tag = '[object Int32Array]',
+      uint8Tag = '[object Uint8Array]',
+      uint8ClampedTag = '[object Uint8ClampedArray]',
+      uint16Tag = '[object Uint16Array]',
+      uint32Tag = '[object Uint32Array]';
+
+  /** Used to match empty string literals in compiled template source. */
   var reEmptyStringLeading = /\b__p \+= '';/g,
       reEmptyStringMiddle = /\b(__p \+=) '' \+/g,
       reEmptyStringTrailing = /(__e\(.*?\)|\b__t\)) \+\n'';/g;
 
+  /** Used to match HTML entities and HTML characters. */
+  var reEscapedHtml = /&(?:amp|lt|gt|quot|#39|#96);/g,
+      reUnescapedHtml = /[&<>"'`]/g,
+      reHasEscapedHtml = RegExp(reEscapedHtml.source),
+      reHasUnescapedHtml = RegExp(reUnescapedHtml.source);
+
+  /** Used to match template delimiters. */
+  var reEscape = /<%-([\s\S]+?)%>/g,
+      reEvaluate = /<%([\s\S]+?)%>/g,
+      reInterpolate = /<%=([\s\S]+?)%>/g;
+
+  /** Used to match property names within property paths. */
+  var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\n\\]|\\.)*?\1)\]/,
+      reIsPlainProp = /^\w*$/,
+      rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\n\\]|\\.)*?)\2)\]/g;
+
   /**
-   * Used to match ES6 template delimiters
-   * http://people.mozilla.org/~jorendorff/es6-draft.html#sec-literals-string-literals
+   * Used to match `RegExp` [syntax characters](http://ecma-international.org/ecma-262/6.0/#sec-patterns)
+   * and those outlined by [`EscapeRegExpPattern`](http://ecma-international.org/ecma-262/6.0/#sec-escaperegexppattern).
    */
+  var reRegExpChars = /^[:!,]|[\\^$.*+?()[\]{}|\/]|(^[0-9a-fA-Fnrtuvx])|([\n\r\u2028\u2029])/g,
+      reHasRegExpChars = RegExp(reRegExpChars.source);
+
+  /** Used to match [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks). */
+  var reComboMark = /[\u0300-\u036f\ufe20-\ufe23]/g;
+
+  /** Used to match backslashes in property paths. */
+  var reEscapeChar = /\\(\\)?/g;
+
+  /** Used to match [ES template delimiters](http://ecma-international.org/ecma-262/6.0/#sec-template-literal-lexical-components). */
   var reEsTemplate = /\$\{([^\\}]*(?:\\.[^\\}]*)*)\}/g;
 
-  /** Used to match regexp flags from their coerced string values */
+  /** Used to match `RegExp` flags from their coerced string values. */
   var reFlags = /\w*$/;
 
-  /** Used to detected named functions */
-  var reFuncName = /^\s*function[ \n\r\t]+\w/;
-
-  /** Used to match "interpolate" template delimiters */
-  var reInterpolate = /<%=([\s\S]+?)%>/g;
-
-  /** Used to match leading whitespace and zeros to be removed */
-  var reLeadingSpacesAndZeros = RegExp('^[' + whitespace + ']*0+(?=.$)');
-
-  /** Used to ensure capturing order of template delimiters */
+  /** Used to detect hexadecimal string values. */
+  var reHasHexPrefix = /^0[xX]/;
+
+  /** Used to detect host constructors (Safari > 5). */
+  var reIsHostCtor = /^\[object .+?Constructor\]$/;
+
+  /** Used to detect unsigned integer values. */
+  var reIsUint = /^\d+$/;
+
+  /** Used to match latin-1 supplementary letters (excluding mathematical operators). */
+  var reLatin1 = /[\xc0-\xd6\xd8-\xde\xdf-\xf6\xf8-\xff]/g;
+
+  /** Used to ensure capturing order of template delimiters. */
   var reNoMatch = /($^)/;
 
-  /** Used to detect functions containing a `this` reference */
-  var reThis = /\bthis\b/;
-
-  /** Used to match unescaped characters in compiled string literals */
-  var reUnescapedString = /['\n\r\t\u2028\u2029\\]/g;
-
-  /** Used to assign default `context` object properties */
+  /** Used to match unescaped characters in compiled string literals. */
+  var reUnescapedString = /['\n\r\u2028\u2029\\]/g;
+
+  /** Used to match words to create compound words. */
+  var reWords = (function() {
+    var upper = '[A-Z\\xc0-\\xd6\\xd8-\\xde]',
+        lower = '[a-z\\xdf-\\xf6\\xf8-\\xff]+';
+
+    return RegExp(upper + '+(?=' + upper + lower + ')|' + upper + '?' + lower + '|' + upper + '+|[0-9]+', 'g');
+  }());
+
+  /** Used to assign default `context` object properties. */
   var contextProps = [
-    'Array', 'Boolean', 'Date', 'Function', 'Math', 'Number', 'Object',
-    'RegExp', 'String', '_', 'attachEvent', 'clearTimeout', 'isFinite', 'isNaN',
-    'parseInt', 'setTimeout'
+    'Array', 'ArrayBuffer', 'Date', 'Error', 'Float32Array', 'Float64Array',
+    'Function', 'Int8Array', 'Int16Array', 'Int32Array', 'Math', 'Number',
+    'Object', 'RegExp', 'Set', 'String', '_', 'clearTimeout', 'isFinite',
+    'parseFloat', 'parseInt', 'setTimeout', 'TypeError', 'Uint8Array',
+    'Uint8ClampedArray', 'Uint16Array', 'Uint32Array', 'WeakMap'
   ];
 
-  /** Used to make template sourceURLs easier to identify */
-  var templateCounter = 0;
-
-  /** `Object#toString` result shortcuts */
-  var argsClass = '[object Arguments]',
-      arrayClass = '[object Array]',
-      boolClass = '[object Boolean]',
-      dateClass = '[object Date]',
-      funcClass = '[object Function]',
-      numberClass = '[object Number]',
-      objectClass = '[object Object]',
-      regexpClass = '[object RegExp]',
-      stringClass = '[object String]';
-
-  /** Used to identify object classifications that `_.clone` supports */
-  var cloneableClasses = {};
-  cloneableClasses[funcClass] = false;
-  cloneableClasses[argsClass] = cloneableClasses[arrayClass] =
-  cloneableClasses[boolClass] = cloneableClasses[dateClass] =
-  cloneableClasses[numberClass] = cloneableClasses[objectClass] =
-  cloneableClasses[regexpClass] = cloneableClasses[stringClass] = true;
-
-  /** Used as an internal `_.debounce` options object */
-  var debounceOptions = {
-    'leading': false,
-    'maxWait': 0,
-    'trailing': false
+  /** Used to make template sourceURLs easier to identify. */
+  var templateCounter = -1;
+
+  /** Used to identify `toStringTag` values of typed arrays. */
+  var typedArrayTags = {};
+  typedArrayTags[float32Tag] = typedArrayTags[float64Tag] =
+  typedArrayTags[int8Tag] = typedArrayTags[int16Tag] =
+  typedArrayTags[int32Tag] = typedArrayTags[uint8Tag] =
+  typedArrayTags[uint8ClampedTag] = typedArrayTags[uint16Tag] =
+  typedArrayTags[uint32Tag] = true;
+  typedArrayTags[argsTag] = typedArrayTags[arrayTag] =
+  typedArrayTags[arrayBufferTag] = typedArrayTags[boolTag] =
+  typedArrayTags[dateTag] = typedArrayTags[errorTag] =
+  typedArrayTags[funcTag] = typedArrayTags[mapTag] =
+  typedArrayTags[numberTag] = typedArrayTags[objectTag] =
+  typedArrayTags[regexpTag] = typedArrayTags[setTag] =
+  typedArrayTags[stringTag] = typedArrayTags[weakMapTag] = false;
+
+  /** Used to identify `toStringTag` values supported by `_.clone`. */
+  var cloneableTags = {};
+  cloneableTags[argsTag] = cloneableTags[arrayTag] =
+  cloneableTags[arrayBufferTag] = cloneableTags[boolTag] =
+  cloneableTags[dateTag] = cloneableTags[float32Tag] =
+  cloneableTags[float64Tag] = cloneableTags[int8Tag] =
+  cloneableTags[int16Tag] = cloneableTags[int32Tag] =
+  cloneableTags[numberTag] = cloneableTags[objectTag] =
+  cloneableTags[regexpTag] = cloneableTags[stringTag] =
+  cloneableTags[uint8Tag] = cloneableTags[uint8ClampedTag] =
+  cloneableTags[uint16Tag] = cloneableTags[uint32Tag] = true;
+  cloneableTags[errorTag] = cloneableTags[funcTag] =
+  cloneableTags[mapTag] = cloneableTags[setTag] =
+  cloneableTags[weakMapTag] = false;
+
+  /** Used to map latin-1 supplementary letters to basic latin letters. */
+  var deburredLetters = {
+    '\xc0': 'A',  '\xc1': 'A', '\xc2': 'A', '\xc3': 'A', '\xc4': 'A', '\xc5': 'A',
+    '\xe0': 'a',  '\xe1': 'a', '\xe2': 'a', '\xe3': 'a', '\xe4': 'a', '\xe5': 'a',
+    '\xc7': 'C',  '\xe7': 'c',
+    '\xd0': 'D',  '\xf0': 'd',
+    '\xc8': 'E',  '\xc9': 'E', '\xca': 'E', '\xcb': 'E',
+    '\xe8': 'e',  '\xe9': 'e', '\xea': 'e', '\xeb': 'e',
+    '\xcC': 'I',  '\xcd': 'I', '\xce': 'I', '\xcf': 'I',
+    '\xeC': 'i',  '\xed': 'i', '\xee': 'i', '\xef': 'i',
+    '\xd1': 'N',  '\xf1': 'n',
+    '\xd2': 'O',  '\xd3': 'O', '\xd4': 'O', '\xd5': 'O', '\xd6': 'O', '\xd8': 'O',
+    '\xf2': 'o',  '\xf3': 'o', '\xf4': 'o', '\xf5': 'o', '\xf6': 'o', '\xf8': 'o',
+    '\xd9': 'U',  '\xda': 'U', '\xdb': 'U', '\xdc': 'U',
+    '\xf9': 'u',  '\xfa': 'u', '\xfb': 'u', '\xfc': 'u',
+    '\xdd': 'Y',  '\xfd': 'y', '\xff': 'y',
+    '\xc6': 'Ae', '\xe6': 'ae',
+    '\xde': 'Th', '\xfe': 'th',
+    '\xdf': 'ss'
   };
 
-  /** Used as the property descriptor for `__bindData__` */
-  var descriptor = {
-    'configurable': false,
-    'enumerable': false,
-    'value': null,
-    'writable': false
+  /** Used to map characters to HTML entities. */
+  var htmlEscapes = {
+    '&': '&amp;',
+    '<': '&lt;',
+    '>': '&gt;',
+    '"': '&quot;',
+    "'": '&#39;',
+    '`': '&#96;'
   };
 
-  /** Used to determine if values are of the language type Object */
+  /** Used to map HTML entities to characters. */
+  var htmlUnescapes = {
+    '&amp;': '&',
+    '&lt;': '<',
+    '&gt;': '>',
+    '&quot;': '"',
+    '&#39;': "'",
+    '&#96;': '`'
+  };
+
+  /** Used to determine if values are of the language type `Object`. */
   var objectTypes = {
-    'boolean': false,
     'function': true,
-    'object': true,
-    'number': false,
-    'string': false,
-    'undefined': false
+    'object': true
   };
 
-  /** Used to escape characters for inclusion in compiled string literals */
+  /** Used to escape characters for inclusion in compiled regexes. */
+  var regexpEscapes = {
+    '0': 'x30', '1': 'x31', '2': 'x32', '3': 'x33', '4': 'x34',
+    '5': 'x35', '6': 'x36', '7': 'x37', '8': 'x38', '9': 'x39',
+    'A': 'x41', 'B': 'x42', 'C': 'x43', 'D': 'x44', 'E': 'x45', 'F': 'x46',
+    'a': 'x61', 'b': 'x62', 'c': 'x63', 'd': 'x64', 'e': 'x65', 'f': 'x66',
+    'n': 'x6e', 'r': 'x72', 't': 'x74', 'u': 'x75', 'v': 'x76', 'x': 'x78'
+  };
+
+  /** Used to escape characters for inclusion in compiled string literals. */
   var stringEscapes = {
     '\\': '\\',
     "'": "'",
     '\n': 'n',
     '\r': 'r',
-    '\t': 't',
     '\u2028': 'u2028',
     '\u2029': 'u2029'
   };
 
-  /** Used as a reference to the global object */
-  var root = (objectTypes[typeof window] && window) || this;
-
-  /** Detect free variable `exports` */
+  /** Detect free variable `exports`. */
   var freeExports = objectTypes[typeof exports] && exports && !exports.nodeType && exports;
 
-  /** Detect free variable `module` */
+  /** Detect free variable `module`. */
   var freeModule = objectTypes[typeof module] && module && !module.nodeType && module;
 
-  /** Detect the popular CommonJS extension `module.exports` */
+  /** Detect free variable `global` from Node.js. */
+  var freeGlobal = freeExports && freeModule && typeof global == 'object' && global && global.Object && global;
+
+  /** Detect free variable `self`. */
+  var freeSelf = objectTypes[typeof self] && self && self.Object && self;
+
+  /** Detect free variable `window`. */
+  var freeWindow = objectTypes[typeof window] && window && window.Object && window;
+
+  /** Detect the popular CommonJS extension `module.exports`. */
   var moduleExports = freeModule && freeModule.exports === freeExports && freeExports;
 
-  /** Detect free variable `global` from Node.js or Browserified code and use it as `root` */
-  var freeGlobal = objectTypes[typeof global] && global;
-  if (freeGlobal && (freeGlobal.global === freeGlobal || freeGlobal.window === freeGlobal)) {
-    root = freeGlobal;
-  }
+  /**
+   * Used as a reference to the global object.
+   *
+   * The `this` value is used if it's the global object to avoid Greasemonkey's
+   * restricted `window` object, otherwise the `window` object is used.
+   */
+  var root = freeGlobal || ((freeWindow !== (this && this.window)) && freeWindow) || freeSelf || this;
 
   /*--------------------------------------------------------------------------*/
 
   /**
-   * The base implementation of `_.indexOf` without support for binary searches
-   * or `fromIndex` constraints.
+   * The base implementation of `compareAscending` which compares values and
+   * sorts them in ascending order without guaranteeing a stable sort.
+   *
+   * @private
+   * @param {*} value The value to compare.
+   * @param {*} other The other value to compare.
+   * @returns {number} Returns the sort order indicator for `value`.
+   */
+  function baseCompareAscending(value, other) {
+    if (value !== other) {
+      var valIsNull = value === null,
+          valIsUndef = value === undefined,
+          valIsReflexive = value === value;
+
+      var othIsNull = other === null,
+          othIsUndef = other === undefined,
+          othIsReflexive = other === other;
+
+      if ((value > other && !othIsNull) || !valIsReflexive ||
+          (valIsNull && !othIsUndef && othIsReflexive) ||
+          (valIsUndef && othIsReflexive)) {
+        return 1;
+      }
+      if ((value < other && !valIsNull) || !othIsReflexive ||
+          (othIsNull && !valIsUndef && valIsReflexive) ||
+          (othIsUndef && valIsReflexive)) {
+        return -1;
+      }
+    }
+    return 0;
+  }
+
+  /**
+   * The base implementation of `_.findIndex` and `_.findLastIndex` without
+   * support for callback shorthands and `this` binding.
+   *
+   * @private
+   * @param {Array} array The array to search.
+   * @param {Function} predicate The function invoked per iteration.
+   * @param {boolean} [fromRight] Specify iterating from right to left.
+   * @returns {number} Returns the index of the matched value, else `-1`.
+   */
+  function baseFindIndex(array, predicate, fromRight) {
+    var length = array.length,
+        index = fromRight ? length : -1;
+
+    while ((fromRight ? index-- : ++index < length)) {
+      if (predicate(array[index], index, array)) {
+        return index;
+      }
+    }
+    return -1;
+  }
+
+  /**
+   * The base implementation of `_.indexOf` without support for binary searches.
    *
    * @private
    * @param {Array} array The array to search.
    * @param {*} value The value to search for.
-   * @param {number} [fromIndex=0] The index to search from.
-   * @returns {number} Returns the index of the matched value or `-1`.
+   * @param {number} fromIndex The index to search from.
+   * @returns {number} Returns the index of the matched value, else `-1`.
    */
   function baseIndexOf(array, value, fromIndex) {
-    var index = (fromIndex || 0) - 1,
-        length = array ? array.length : 0;
+    if (value !== value) {
+      return indexOfNaN(array, fromIndex);
+    }
+    var index = fromIndex - 1,
+        length = array.length;
 
     while (++index < length) {
       if (array[index] === value) {
@@ -180,266 +355,357 @@
   }
 
   /**
-   * An implementation of `_.contains` for cache objects that mimics the return
-   * signature of `_.indexOf` by returning `0` if the value is found, else `-1`.
+   * The base implementation of `_.isFunction` without support for environments
+   * with incorrect `typeof` results.
+   *
+   * @private
+   * @param {*} value The value to check.
+   * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+   */
+  function baseIsFunction(value) {
+    // Avoid a Chakra JIT bug in compatibility modes of IE 11.
+    // See https://github.com/jashkenas/underscore/issues/1621 for more details.
+    return typeof value == 'function' || false;
+  }
+
+  /**
+   * Converts `value` to a string if it's not one. An empty string is returned
+   * for `null` or `undefined` values.
    *
    * @private
-   * @param {Object} cache The cache object to inspect.
-   * @param {*} value The value to search for.
-   * @returns {number} Returns `0` if `value` is found, else `-1`.
+   * @param {*} value The value to process.
+   * @returns {string} Returns the string.
    */
-  function cacheIndexOf(cache, value) {
-    var type = typeof value;
-    cache = cache.cache;
-
-    if (type == 'boolean' || value == null) {
-      return cache[value] ? 0 : -1;
-    }
-    if (type != 'number' && type != 'string') {
-      type = 'object';
-    }
-    var key = type == 'number' ? value : keyPrefix + value;
-    cache = (cache = cache[type]) && cache[key];
-
-    return type == 'object'
-      ? (cache && baseIndexOf(cache, value) > -1 ? 0 : -1)
-      : (cache ? 0 : -1);
+  function baseToString(value) {
+    return value == null ? '' : (value + '');
+  }
+
+  /**
+   * Used by `_.trim` and `_.trimLeft` to get the index of the first character
+   * of `string` that is not found in `chars`.
+   *
+   * @private
+   * @param {string} string The string to inspect.
+   * @param {string} chars The characters to find.
+   * @returns {number} Returns the index of the first character not found in `chars`.
+   */
+  function charsLeftIndex(string, chars) {
+    var index = -1,
+        length = string.length;
+
+    while (++index < length && chars.indexOf(string.charAt(index)) > -1) {}
+    return index;
   }
 
   /**
-   * Adds a given value to the corresponding cache object.
+   * Used by `_.trim` and `_.trimRight` to get the index of the last character
+   * of `string` that is not found in `chars`.
+   *
+   * @private
+   * @param {string} string The string to inspect.
+   * @param {string} chars The characters to find.
+   * @returns {number} Returns the index of the last character not found in `chars`.
+   */
+  function charsRightIndex(string, chars) {
+    var index = string.length;
+
+    while (index-- && chars.indexOf(string.charAt(index)) > -1) {}
+    return index;
+  }
+
+  /**
+   * Used by `_.sortBy` to compare transformed elements of a collection and stable
+   * sort them in ascending order.
    *
    * @private
-   * @param {*} value The value to add to the cache.
+   * @param {Object} object The object to compare.
+   * @param {Object} other The other object to compare.
+   * @returns {number} Returns the sort order indicator for `object`.
+   */
+  function compareAscending(object, other) {
+    return baseCompareAscending(object.criteria, other.criteria) || (object.index - other.index);
+  }
+
+  /**
+   * Used by `_.sortByOrder` to compare multiple properties of a value to another
+   * and stable sort them.
+   *
+   * If `orders` is unspecified, all valuess are sorted in ascending order. Otherwise,
+   * a value is sorted in ascending order if its corresponding order is "asc", and
+   * descending if "desc".
+   *
+   * @private
+   * @param {Object} object The object to compare.
+   * @param {Object} other The other object to compare.
+   * @param {boolean[]} orders The order to sort by for each property.
+   * @returns {number} Returns the sort order indicator for `object`.
    */
-  function cachePush(value) {
-    var cache = this.cache,
-        type = typeof value;
-
-    if (type == 'boolean' || value == null) {
-      cache[value] = true;
-    } else {
-      if (type != 'number' && type != 'string') {
-        type = 'object';
-      }
-      var key = type == 'number' ? value : keyPrefix + value,
-          typeCache = cache[type] || (cache[type] = {});
-
-      if (type == 'object') {
-        (typeCache[key] || (typeCache[key] = [])).push(value);
-      } else {
-        typeCache[key] = true;
-      }
-    }
+  function compareMultiple(object, other, orders) {
+    var index = -1,
+        objCriteria = object.criteria,
+        othCriteria = other.criteria,
+        length = objCriteria.length,
+        ordersLength = orders.length;
+
+    while (++index < length) {
+      var result = baseCompareAscending(objCriteria[index], othCriteria[index]);
+      if (result) {
+        if (index >= ordersLength) {
+          return result;
+        }
+        var order = orders[index];
+        return result * ((order === 'asc' || order === true) ? 1 : -1);
+      }
+    }
+    // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications
+    // that causes it, under certain circumstances, to provide the same value for
+    // `object` and `other`. See https://github.com/jashkenas/underscore/pull/1247
+    // for more details.
+    //
+    // This also ensures a stable sort in V8 and other engines.
+    // See https://code.google.com/p/v8/issues/detail?id=90 for more details.
+    return object.index - other.index;
   }
 
   /**
-   * Used by `_.max` and `_.min` as the default callback when a given
-   * collection is a string value.
+   * Used by `_.deburr` to convert latin-1 supplementary letters to basic latin letters.
+   *
+   * @private
+   * @param {string} letter The matched letter to deburr.
+   * @returns {string} Returns the deburred letter.
+   */
+  function deburrLetter(letter) {
+    return deburredLetters[letter];
+  }
+
+  /**
+   * Used by `_.escape` to convert characters to HTML entities.
    *
    * @private
-   * @param {string} value The character to inspect.
-   * @returns {number} Returns the code unit of given character.
+   * @param {string} chr The matched character to escape.
+   * @returns {string} Returns the escaped character.
+   */
+  function escapeHtmlChar(chr) {
+    return htmlEscapes[chr];
+  }
+
+  /**
+   * Used by `_.escapeRegExp` to escape characters for inclusion in compiled regexes.
+   *
+   * @private
+   * @param {string} chr The matched character to escape.
+   * @param {string} leadingChar The capture group for a leading character.
+   * @param {string} whitespaceChar The capture group for a whitespace character.
+   * @returns {string} Returns the escaped character.
    */
-  function charAtCallback(value) {
-    return value.charCodeAt(0);
+  function escapeRegExpChar(chr, leadingChar, whitespaceChar) {
+    if (leadingChar) {
+      chr = regexpEscapes[chr];
+    } else if (whitespaceChar) {
+      chr = stringEscapes[chr];
+    }
+    return '\\' + chr;
+  }
+
+  /**
+   * Used by `_.template` to escape characters for inclusion in compiled string literals.
+   *
+   * @private
+   * @param {string} chr The matched character to escape.
+   * @returns {string} Returns the escaped character.
+   */
+  function escapeStringChar(chr) {
+    return '\\' + stringEscapes[chr];
   }
 
   /**
-   * Used by `sortBy` to compare transformed `collection` elements, stable sorting
-   * them in ascending order.
+   * Gets the index at which the first occurrence of `NaN` is found in `array`.
    *
    * @private
-   * @param {Object} a The object to compare to `b`.
-   * @param {Object} b The object to compare to `a`.
-   * @returns {number} Returns the sort order indicator of `1` or `-1`.
+   * @param {Array} array The array to search.
+   * @param {number} fromIndex The index to search from.
+   * @param {boolean} [fromRight] Specify iterating from right to left.
+   * @returns {number} Returns the index of the matched `NaN`, else `-1`.
    */
-  function compareAscending(a, b) {
-    var ac = a.criteria,
-        bc = b.criteria,
-        index = -1,
-        length = ac.length;
-
-    while (++index < length) {
-      var value = ac[index],
-          other = bc[index];
-
-      if (value !== other) {
-        if (value > other || typeof value == 'undefined') {
-          return 1;
-        }
-        if (value < other || typeof other == 'undefined') {
-          return -1;
-        }
-      }
-    }
-    // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications
-    // that causes it, under certain circumstances, to return the same value for
-    // `a` and `b`. See https://github.com/jashkenas/underscore/pull/1247
-    //
-    // This also ensures a stable sort in V8 and other engines.
-    // See http://code.google.com/p/v8/issues/detail?id=90
-    return a.index - b.index;
+  function indexOfNaN(array, fromIndex, fromRight) {
+    var length = array.length,
+        index = fromIndex + (fromRight ? 0 : -1);
+
+    while ((fromRight ? index-- : ++index < length)) {
+      var other = array[index];
+      if (other !== other) {
+        return index;
+      }
+    }
+    return -1;
+  }
+
+  /**
+   * Checks if `value` is object-like.
+   *
+   * @private
+   * @param {*} value The value to check.
+   * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
+   */
+  function isObjectLike(value) {
+    return !!value && typeof value == 'object';
   }
 
   /**
-   * Creates a cache object to optimize linear searches of large arrays.
+   * Used by `trimmedLeftIndex` and `trimmedRightIndex` to determine if a
+   * character code is whitespace.
    *
    * @private
-   * @param {Array} [array=[]] The array to search.
-   * @returns {null|Object} Returns the cache object or `null` if caching should not be used.
+   * @param {number} charCode The character code to inspect.
+   * @returns {boolean} Returns `true` if `charCode` is whitespace, else `false`.
    */
-  function createCache(array) {
+  function isSpace(charCode) {
+    return ((charCode <= 160 && (charCode >= 9 && charCode <= 13) || charCode == 32 || charCode == 160) || charCode == 5760 || charCode == 6158 ||
+      (charCode >= 8192 && (charCode <= 8202 || charCode == 8232 || charCode == 8233 || charCode == 8239 || charCode == 8287 || charCode == 12288 || charCode == 65279)));
+  }
+
+  /**
+   * Replaces all `placeholder` elements in `array` with an internal placeholder
+   * and returns an array of their indexes.
+   *
+   * @private
+   * @param {Array} array The array to modify.
+   * @param {*} placeholder The placeholder to replace.
+   * @returns {Array} Returns the new array of placeholder indexes.
+   */
+  function replaceHolders(array, placeholder) {
     var index = -1,
         length = array.length,
-        first = array[0],
-        mid = array[(length / 2) | 0],
-        last = array[length - 1];
-
-    if (first && typeof first == 'object' &&
-        mid && typeof mid == 'object' && last && typeof last == 'object') {
-      return false;
-    }
-    var cache = getObject();
-    cache['false'] = cache['null'] = cache['true'] = cache['undefined'] = false;
-
-    var result = getObject();
-    result.array = array;
-    result.cache = cache;
-    result.push = cachePush;
+        resIndex = -1,
+        result = [];
 
     while (++index < length) {
-      result.push(array[index]);
+      if (array[index] === placeholder) {
+        array[index] = PLACEHOLDER;
+        result[++resIndex] = index;
+      }
     }
     return result;
   }
 
   /**
-   * Used by `template` to escape characters for inclusion in compiled
-   * string literals.
-   *
-   * @private
-   * @param {string} match The matched character to escape.
-   * @returns {string} Returns the escaped character.
-   */
-  function escapeStringChar(match) {
-    return '\\' + stringEscapes[match];
-  }
-
-  /**
-   * Gets an array from the array pool or creates a new one if the pool is empty.
+   * An implementation of `_.uniq` optimized for sorted arrays without support
+   * for callback shorthands and `this` binding.
    *
    * @private
-   * @returns {Array} The array from the pool.
-   */
-  function getArray() {
-    return arrayPool.pop() || [];
-  }
-
-  /**
-   * Gets an object from the object pool or creates a new one if the pool is empty.
-   *
-   * @private
-   * @returns {Object} The object from the pool.
+   * @param {Array} array The array to inspect.
+   * @param {Function} [iteratee] The function invoked per iteration.
+   * @returns {Array} Returns the new duplicate free array.
    */
-  function getObject() {
-    return objectPool.pop() || {
-      'array': null,
-      'cache': null,
-      'criteria': null,
-      'false': false,
-      'index': 0,
-      'null': false,
-      'number': null,
-      'object': null,
-      'push': null,
-      'string': null,
-      'true': false,
-      'undefined': false,
-      'value': null
-    };
+  function sortedUniq(array, iteratee) {
+    var seen,
+        index = -1,
+        length = array.length,
+        resIndex = -1,
+        result = [];
+
+    while (++index < length) {
+      var value = array[index],
+          computed = iteratee ? iteratee(value, index, array) : value;
+
+      if (!index || seen !== computed) {
+        seen = computed;
+        result[++resIndex] = value;
+      }
+    }
+    return result;
   }
 
   /**
-   * Releases the given array back to the array pool.
+   * Used by `_.trim` and `_.trimLeft` to get the index of the first non-whitespace
+   * character of `string`.
    *
    * @private
-   * @param {Array} [array] The array to release.
+   * @param {string} string The string to inspect.
+   * @returns {number} Returns the index of the first non-whitespace character.
    */
-  function releaseArray(array) {
-    array.length = 0;
-    if (arrayPool.length < maxPoolSize) {
-      arrayPool.push(array);
-    }
+  function trimmedLeftIndex(string) {
+    var index = -1,
+        length = string.length;
+
+    while (++index < length && isSpace(string.charCodeAt(index))) {}
+    return index;
   }
 
   /**
-   * Releases the given object back to the object pool.
+   * Used by `_.trim` and `_.trimRight` to get the index of the last non-whitespace
+   * character of `string`.
    *
    * @private
-   * @param {Object} [object] The object to release.
+   * @param {string} string The string to inspect.
+   * @returns {number} Returns the index of the last non-whitespace character.
    */
-  function releaseObject(object) {
-    var cache = object.cache;
-    if (cache) {
-      releaseObject(cache);
-    }
-    object.array = object.cache = object.criteria = object.object = object.number = object.string = object.value = null;
-    if (objectPool.length < maxPoolSize) {
-      objectPool.push(object);
-    }
+  function trimmedRightIndex(string) {
+    var index = string.length;
+
+    while (index-- && isSpace(string.charCodeAt(index))) {}
+    return index;
   }
 
   /**
-   * Slices the `collection` from the `start` index up to, but not including,
-   * the `end` index.
-   *
-   * Note: This function is used instead of `Array#slice` to support node lists
-   * in IE < 9 and to ensure dense arrays are returned.
+   * Used by `_.unescape` to convert HTML entities to characters.
    *
    * @private
-   * @param {Array|Object|string} collection The collection to slice.
-   * @param {number} start The start index.
-   * @param {number} end The end index.
-   * @returns {Array} Returns the new array.
+   * @param {string} chr The matched character to unescape.
+   * @returns {string} Returns the unescaped character.
    */
-  function slice(array, start, end) {
-    start || (start = 0);
-    if (typeof end == 'undefined') {
-      end = array ? array.length : 0;
-    }
-    var index = -1,
-        length = end - start || 0,
-        result = Array(length < 0 ? 0 : length);
-
-    while (++index < length) {
-      result[index] = array[start + index];
-    }
-    return result;
+  function unescapeHtmlChar(chr) {
+    return htmlUnescapes[chr];
   }
 
   /*--------------------------------------------------------------------------*/
 
   /**
-   * Create a new `lodash` function using the given context object.
+   * Create a new pristine `lodash` function using the given `context` object.
    *
    * @static
    * @memberOf _
-   * @category Utilities
+   * @category Utility
    * @param {Object} [context=root] The context object.
-   * @returns {Function} Returns the `lodash` function.
+   * @returns {Function} Returns a new `lodash` function.
+   * @example
+   *
+   * _.mixin({ 'foo': _.constant('foo') });
+   *
+   * var lodash = _.runInContext();
+   * lodash.mixin({ 'bar': lodash.constant('bar') });
+   *
+   * _.isFunction(_.foo);
+   * // => true
+   * _.isFunction(_.bar);
+   * // => false
+   *
+   * lodash.isFunction(lodash.foo);
+   * // => false
+   * lodash.isFunction(lodash.bar);
+   * // => true
+   *
+   * // using `context` to mock `Date#getTime` use in `_.now`
+   * var mock = _.runInContext({
+   *   'Date': function() {
+   *     return { 'getTime': getTimeMock };
+   *   }
+   * });
+   *
+   * // or creating a suped-up `defer` in Node.js
+   * var defer = _.runInContext({ 'setTimeout': setImmediate }).defer;
    */
   function runInContext(context) {
     // Avoid issues with some ES3 environments that attempt to use values, named
     // after built-in constructors like `Object`, for the creation of literals.
     // ES5 clears this up by stating that literals must use built-in constructors.
-    // See http://es5.github.io/#x11.1.5.
+    // See https://es5.github.io/#x11.1.5 for more details.
     context = context ? _.defaults(root.Object(), context, _.pick(root, contextProps)) : root;
 
-    /** Native constructor references */
+    /** Native constructor references. */
     var Array = context.Array,
-        Boolean = context.Boolean,
         Date = context.Date,
+        Error = context.Error,
         Function = context.Function,
         Math = context.Math,
         Number = context.Number,
@@ -448,134 +714,171 @@
         String = context.String,
         TypeError = context.TypeError;
 
-    /**
-     * Used for `Array` method references.
-     *
-     * Normally `Array.prototype` would suffice, however, using an array literal
-     * avoids issues in Narwhal.
-     */
-    var arrayRef = [];
-
-    /** Used for native method references */
-    var objectProto = Object.prototype;
-
-    /** Used to restore the original `_` reference in `noConflict` */
-    var oldDash = context._;
-
-    /** Used to resolve the internal [[Class]] of values */
-    var toString = objectProto.toString;
-
-    /** Used to detect if a method is native */
-    var reNative = RegExp('^' +
-      String(toString)
-        .replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
-        .replace(/toString| for [^\]]+/g, '.*?') + '$'
+    /** Used for native method references. */
+    var arrayProto = Array.prototype,
+        objectProto = Object.prototype,
+        stringProto = String.prototype;
+
+    /** Used to resolve the decompiled source of functions. */
+    var fnToString = Function.prototype.toString;
+
+    /** Used to check objects for own properties. */
+    var hasOwnProperty = objectProto.hasOwnProperty;
+
+    /** Used to generate unique IDs. */
+    var idCounter = 0;
+
+    /**
+     * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
+     * of values.
+     */
+    var objToString = objectProto.toString;
+
+    /** Used to restore the original `_` reference in `_.noConflict`. */
+    var oldDash = root._;
+
+    /** Used to detect if a method is native. */
+    var reIsNative = RegExp('^' +
+      fnToString.call(hasOwnProperty).replace(/[\\^$.*+?()[\]{}|]/g, '\\$&')
+      .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
     );
 
-    /** Native method shortcuts */
-    var ceil = Math.ceil,
+    /** Native method references. */
+    var ArrayBuffer = context.ArrayBuffer,
         clearTimeout = context.clearTimeout,
-        floor = Math.floor,
-        fnToString = Function.prototype.toString,
-        getPrototypeOf = isNative(getPrototypeOf = Object.getPrototypeOf) && getPrototypeOf,
-        hasOwnProperty = objectProto.hasOwnProperty,
-        push = arrayRef.push,
+        parseFloat = context.parseFloat,
+        pow = Math.pow,
+        propertyIsEnumerable = objectProto.propertyIsEnumerable,
+        Set = getNative(context, 'Set'),
         setTimeout = context.setTimeout,
-        splice = arrayRef.splice,
-        unshift = arrayRef.unshift;
-
-    /** Used to set meta data on functions */
-    var defineProperty = (function() {
-      // IE 8 only accepts DOM elements
-      try {
-        var o = {},
-            func = isNative(func = Object.defineProperty) && func,
-            result = func(o, o, o) && func;
-      } catch(e) { }
-      return result;
-    }());
-
-    /* Native method shortcuts for methods with the same name as other `lodash` methods */
-    var nativeCreate = isNative(nativeCreate = Object.create) && nativeCreate,
-        nativeIsArray = isNative(nativeIsArray = Array.isArray) && nativeIsArray,
+        splice = arrayProto.splice,
+        Uint8Array = context.Uint8Array,
+        WeakMap = getNative(context, 'WeakMap');
+
+    /* Native method references for those with the same name as other `lodash` methods. */
+    var nativeCeil = Math.ceil,
+        nativeCreate = getNative(Object, 'create'),
+        nativeFloor = Math.floor,
+        nativeIsArray = getNative(Array, 'isArray'),
         nativeIsFinite = context.isFinite,
-        nativeIsNaN = context.isNaN,
-        nativeKeys = isNative(nativeKeys = Object.keys) && nativeKeys,
+        nativeKeys = getNative(Object, 'keys'),
         nativeMax = Math.max,
         nativeMin = Math.min,
+        nativeNow = getNative(Date, 'now'),
         nativeParseInt = context.parseInt,
         nativeRandom = Math.random;
 
-    /** Used to lookup a built-in constructor by [[Class]] */
-    var ctorByClass = {};
-    ctorByClass[arrayClass] = Array;
-    ctorByClass[boolClass] = Boolean;
-    ctorByClass[dateClass] = Date;
-    ctorByClass[funcClass] = Function;
-    ctorByClass[objectClass] = Object;
-    ctorByClass[numberClass] = Number;
-    ctorByClass[regexpClass] = RegExp;
-    ctorByClass[stringClass] = String;
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates a `lodash` object which wraps the given value to enable intuitive
-     * method chaining.
-     *
-     * In addition to Lo-Dash methods, wrappers also have the following `Array` methods:
-     * `concat`, `join`, `pop`, `push`, `reverse`, `shift`, `slice`, `sort`, `splice`,
-     * and `unshift`
-     *
-     * Chaining is supported in custom builds as long as the `value` method is
-     * implicitly or explicitly included in the build.
-     *
-     * The chainable wrapper functions are:
-     * `after`, `assign`, `bind`, `bindAll`, `bindKey`, `chain`, `compact`,
-     * `compose`, `concat`, `countBy`, `create`, `createCallback`, `curry`,
-     * `debounce`, `defaults`, `defer`, `delay`, `difference`, `filter`, `flatten`,
+    /** Used as references for `-Infinity` and `Infinity`. */
+    var NEGATIVE_INFINITY = Number.NEGATIVE_INFINITY,
+        POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
+
+    /** Used as references for the maximum length and index of an array. */
+    var MAX_ARRAY_LENGTH = 4294967295,
+        MAX_ARRAY_INDEX = MAX_ARRAY_LENGTH - 1,
+        HALF_MAX_ARRAY_LENGTH = MAX_ARRAY_LENGTH >>> 1;
+
+    /**
+     * Used as the [maximum length](http://ecma-international.org/ecma-262/6.0/#sec-number.max_safe_integer)
+     * of an array-like value.
+     */
+    var MAX_SAFE_INTEGER = 9007199254740991;
+
+    /** Used to store function metadata. */
+    var metaMap = WeakMap && new WeakMap;
+
+    /** Used to lookup unminified function names. */
+    var realNames = {};
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a `lodash` object which wraps `value` to enable implicit chaining.
+     * Methods that operate on and return arrays, collections, and functions can
+     * be chained together. Methods that retrieve a single value or may return a
+     * primitive value will automatically end the chain returning the unwrapped
+     * value. Explicit chaining may be enabled using `_.chain`. The execution of
+     * chained methods is lazy, that is, execution is deferred until `_#value`
+     * is implicitly or explicitly called.
+     *
+     * Lazy evaluation allows several methods to support shortcut fusion. Shortcut
+     * fusion is an optimization strategy which merge iteratee calls; this can help
+     * to avoid the creation of intermediate data structures and greatly reduce the
+     * number of iteratee executions.
+     *
+     * Chaining is supported in custom builds as long as the `_#value` method is
+     * directly or indirectly included in the build.
+     *
+     * In addition to lodash methods, wrappers have `Array` and `String` methods.
+     *
+     * The wrapper `Array` methods are:
+     * `concat`, `join`, `pop`, `push`, `reverse`, `shift`, `slice`, `sort`,
+     * `splice`, and `unshift`
+     *
+     * The wrapper `String` methods are:
+     * `replace` and `split`
+     *
+     * The wrapper methods that support shortcut fusion are:
+     * `compact`, `drop`, `dropRight`, `dropRightWhile`, `dropWhile`, `filter`,
+     * `first`, `initial`, `last`, `map`, `pluck`, `reject`, `rest`, `reverse`,
+     * `slice`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, `toArray`,
+     * and `where`
+     *
+     * The chainable wrapper methods are:
+     * `after`, `ary`, `assign`, `at`, `before`, `bind`, `bindAll`, `bindKey`,
+     * `callback`, `chain`, `chunk`, `commit`, `compact`, `concat`, `constant`,
+     * `countBy`, `create`, `curry`, `debounce`, `defaults`, `defaultsDeep`,
+     * `defer`, `delay`, `difference`, `drop`, `dropRight`, `dropRightWhile`,
+     * `dropWhile`, `fill`, `filter`, `flatten`, `flattenDeep`, `flow`, `flowRight`,
      * `forEach`, `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`,
      * `functions`, `groupBy`, `indexBy`, `initial`, `intersection`, `invert`,
-     * `invoke`, `keys`, `map`, `max`, `memoize`, `merge`, `min`, `object`, `omit`,
-     * `once`, `pairs`, `partial`, `partialRight`, `pick`, `pluck`, `pull`, `push`,
-     * `range`, `reject`, `remove`, `rest`, `reverse`, `shuffle`, `slice`, `sort`,
-     * `sortBy`, `splice`, `tap`, `throttle`, `times`, `toArray`, `transform`,
-     * `union`, `uniq`, `unshift`, `unzip`, `values`, `where`, `without`, `wrap`,
-     * and `zip`
-     *
-     * The non-chainable wrapper functions are:
-     * `clone`, `cloneDeep`, `contains`, `escape`, `every`, `find`, `findIndex`,
-     * `findKey`, `findLast`, `findLastIndex`, `findLastKey`, `has`, `identity`,
-     * `indexOf`, `isArguments`, `isArray`, `isBoolean`, `isDate`, `isElement`,
-     * `isEmpty`, `isEqual`, `isFinite`, `isFunction`, `isNaN`, `isNull`, `isNumber`,
-     * `isObject`, `isPlainObject`, `isRegExp`, `isString`, `isUndefined`, `join`,
-     * `lastIndexOf`, `mixin`, `noConflict`, `parseInt`, `pop`, `random`, `reduce`,
-     * `reduceRight`, `result`, `shift`, `size`, `some`, `sortedIndex`, `runInContext`,
-     * `template`, `unescape`, `uniqueId`, and `value`
-     *
-     * The wrapper functions `first` and `last` return wrapped values when `n` is
-     * provided, otherwise they return unwrapped values.
-     *
-     * Explicit chaining can be enabled by using the `_.chain` method.
+     * `invoke`, `keys`, `keysIn`, `map`, `mapKeys`, `mapValues`, `matches`,
+     * `matchesProperty`, `memoize`, `merge`, `method`, `methodOf`, `mixin`,
+     * `modArgs`, `negate`, `omit`, `once`, `pairs`, `partial`, `partialRight`,
+     * `partition`, `pick`, `plant`, `pluck`, `property`, `propertyOf`, `pull`,
+     * `pullAt`, `push`, `range`, `rearg`, `reject`, `remove`, `rest`, `restParam`,
+     * `reverse`, `set`, `shuffle`, `slice`, `sort`, `sortBy`, `sortByAll`,
+     * `sortByOrder`, `splice`, `spread`, `take`, `takeRight`, `takeRightWhile`,
+     * `takeWhile`, `tap`, `throttle`, `thru`, `times`, `toArray`, `toPlainObject`,
+     * `transform`, `union`, `uniq`, `unshift`, `unzip`, `unzipWith`, `values`,
+     * `valuesIn`, `where`, `without`, `wrap`, `xor`, `zip`, `zipObject`, `zipWith`
+     *
+     * The wrapper methods that are **not** chainable by default are:
+     * `add`, `attempt`, `camelCase`, `capitalize`, `ceil`, `clone`, `cloneDeep`,
+     * `deburr`, `endsWith`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`,
+     * `findKey`, `findLast`, `findLastIndex`, `findLastKey`, `findWhere`, `first`,
+     * `floor`, `get`, `gt`, `gte`, `has`, `identity`, `includes`, `indexOf`,
+     * `inRange`, `isArguments`, `isArray`, `isBoolean`, `isDate`, `isElement`,
+     * `isEmpty`, `isEqual`, `isError`, `isFinite` `isFunction`, `isMatch`,
+     * `isNative`, `isNaN`, `isNull`, `isNumber`, `isObject`, `isPlainObject`,
+     * `isRegExp`, `isString`, `isUndefined`, `isTypedArray`, `join`, `kebabCase`,
+     * `last`, `lastIndexOf`, `lt`, `lte`, `max`, `min`, `noConflict`, `noop`,
+     * `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`, `random`, `reduce`,
+     * `reduceRight`, `repeat`, `result`, `round`, `runInContext`, `shift`, `size`,
+     * `snakeCase`, `some`, `sortedIndex`, `sortedLastIndex`, `startCase`,
+     * `startsWith`, `sum`, `template`, `trim`, `trimLeft`, `trimRight`, `trunc`,
+     * `unescape`, `uniqueId`, `value`, and `words`
+     *
+     * The wrapper method `sample` will return a wrapped value when `n` is provided,
+     * otherwise an unwrapped value is returned.
      *
      * @name _
      * @constructor
-     * @category Chaining
+     * @category Chain
      * @param {*} value The value to wrap in a `lodash` instance.
-     * @returns {Object} Returns a `lodash` instance.
+     * @returns {Object} Returns the new `lodash` wrapper instance.
      * @example
      *
      * var wrapped = _([1, 2, 3]);
      *
      * // returns an unwrapped value
-     * wrapped.reduce(function(sum, num) {
-     *   return sum + num;
+     * wrapped.reduce(function(total, n) {
+     *   return total + n;
      * });
      * // => 6
      *
      * // returns a wrapped value
-     * var squares = wrapped.map(function(num) {
-     *   return num * num;
+     * var squares = wrapped.map(function(n) {
+     *   return n * n;
      * });
      *
      * _.isArray(squares);
@@ -585,29 +888,42 @@
      * // => true
      */
     function lodash(value) {
-      // don't wrap if already wrapped, even if wrapped by a different `lodash` constructor
-      return (value && typeof value == 'object' && !isArray(value) && hasOwnProperty.call(value, '__wrapped__'))
-       ? value
-       : new lodashWrapper(value);
-    }
-
-    /**
-     * A fast path for creating `lodash` wrapper objects.
-     *
-     * @private
-     * @param {*} value The value to wrap in a `lodash` instance.
-     * @param {boolean} chainAll A flag to enable chaining for all methods
-     * @returns {Object} Returns a `lodash` instance.
-     */
-    function lodashWrapper(value, chainAll) {
+      if (isObjectLike(value) && !isArray(value) && !(value instanceof LazyWrapper)) {
+        if (value instanceof LodashWrapper) {
+          return value;
+        }
+        if (hasOwnProperty.call(value, '__chain__') && hasOwnProperty.call(value, '__wrapped__')) {
+          return wrapperClone(value);
+        }
+      }
+      return new LodashWrapper(value);
+    }
+
+    /**
+     * The function whose prototype all chaining wrappers inherit from.
+     *
+     * @private
+     */
+    function baseLodash() {
+      // No operation performed.
+    }
+
+    /**
+     * The base constructor for creating `lodash` wrapper objects.
+     *
+     * @private
+     * @param {*} value The value to wrap.
+     * @param {boolean} [chainAll] Enable chaining for all wrapper methods.
+     * @param {Array} [actions=[]] Actions to peform to resolve the unwrapped value.
+     */
+    function LodashWrapper(value, chainAll, actions) {
+      this.__wrapped__ = value;
+      this.__actions__ = actions || [];
       this.__chain__ = !!chainAll;
-      this.__wrapped__ = value;
-    }
-    // ensure `new lodashWrapper` is an instance of `lodash`
-    lodashWrapper.prototype = lodash.prototype;
-
-    /**
-     * An object used to flag environments features.
+    }
+
+    /**
+     * An object environment feature flags.
      *
      * @static
      * @memberOf _
@@ -616,26 +932,9 @@
     var support = lodash.support = {};
 
     /**
-     * Detect if functions can be decompiled by `Function#toString`
-     * (all but PS3 and older Opera mobile browsers & avoided in Windows 8 apps).
-     *
-     * @memberOf _.support
-     * @type boolean
-     */
-    support.funcDecomp = !isNative(context.WinRTError) && reThis.test(runInContext);
-
-    /**
-     * Detect if `Function#name` is supported (all but IE).
-     *
-     * @memberOf _.support
-     * @type boolean
-     */
-    support.funcNames = typeof Function.name == 'string';
-
-    /**
-     * By default, the template delimiters used by Lo-Dash are similar to those in
-     * embedded Ruby (ERB). Change the following template settings to use alternative
-     * delimiters.
+     * By default, the template delimiters used by lodash are like those in
+     * embedded Ruby (ERB). Change the following template settings to use
+     * alternative delimiters.
      *
      * @static
      * @memberOf _
@@ -649,7 +948,7 @@
        * @memberOf _.templateSettings
        * @type RegExp
        */
-      'escape': /<%-([\s\S]+?)%>/g,
+      'escape': reEscape,
 
       /**
        * Used to detect code to be evaluated.
@@ -657,7 +956,7 @@
        * @memberOf _.templateSettings
        * @type RegExp
        */
-      'evaluate': /<%([\s\S]+?)%>/g,
+      'evaluate': reEvaluate,
 
       /**
        * Used to detect `data` property values to inject.
@@ -693,134 +992,747 @@
       }
     };
 
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * The base implementation of `_.bind` that creates the bound function and
-     * sets its meta data.
-     *
-     * @private
-     * @param {Array} bindData The bind data array.
-     * @returns {Function} Returns the new bound function.
-     */
-    function baseBind(bindData) {
-      var func = bindData[0],
-          partialArgs = bindData[2],
-          thisArg = bindData[4];
-
-      function bound() {
-        // `Function#bind` spec
-        // http://es5.github.io/#x15.3.4.5
-        if (partialArgs) {
-          // avoid `arguments` object deoptimizations by using `slice` instead
-          // of `Array.prototype.slice.call` and not assigning `arguments` to a
-          // variable as a ternary expression
-          var args = slice(partialArgs);
-          push.apply(args, arguments);
-        }
-        // mimic the constructor's `return` behavior
-        // http://es5.github.io/#x13.2.2
-        if (this instanceof bound) {
-          // ensure `new bound` is an instance of `func`
-          var thisBinding = baseCreate(func.prototype),
-              result = func.apply(thisBinding, args || arguments);
-          return isObject(result) ? result : thisBinding;
-        }
-        return func.apply(thisArg, args || arguments);
-      }
-      setBindData(bound, bindData);
-      return bound;
-    }
-
-    /**
-     * The base implementation of `_.clone` without argument juggling or support
-     * for `thisArg` binding.
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a lazy wrapper object which wraps `value` to enable lazy evaluation.
+     *
+     * @private
+     * @param {*} value The value to wrap.
+     */
+    function LazyWrapper(value) {
+      this.__wrapped__ = value;
+      this.__actions__ = [];
+      this.__dir__ = 1;
+      this.__filtered__ = false;
+      this.__iteratees__ = [];
+      this.__takeCount__ = POSITIVE_INFINITY;
+      this.__views__ = [];
+    }
+
+    /**
+     * Creates a clone of the lazy wrapper object.
+     *
+     * @private
+     * @name clone
+     * @memberOf LazyWrapper
+     * @returns {Object} Returns the cloned `LazyWrapper` object.
+     */
+    function lazyClone() {
+      var result = new LazyWrapper(this.__wrapped__);
+      result.__actions__ = arrayCopy(this.__actions__);
+      result.__dir__ = this.__dir__;
+      result.__filtered__ = this.__filtered__;
+      result.__iteratees__ = arrayCopy(this.__iteratees__);
+      result.__takeCount__ = this.__takeCount__;
+      result.__views__ = arrayCopy(this.__views__);
+      return result;
+    }
+
+    /**
+     * Reverses the direction of lazy iteration.
+     *
+     * @private
+     * @name reverse
+     * @memberOf LazyWrapper
+     * @returns {Object} Returns the new reversed `LazyWrapper` object.
+     */
+    function lazyReverse() {
+      if (this.__filtered__) {
+        var result = new LazyWrapper(this);
+        result.__dir__ = -1;
+        result.__filtered__ = true;
+      } else {
+        result = this.clone();
+        result.__dir__ *= -1;
+      }
+      return result;
+    }
+
+    /**
+     * Extracts the unwrapped value from its lazy wrapper.
+     *
+     * @private
+     * @name value
+     * @memberOf LazyWrapper
+     * @returns {*} Returns the unwrapped value.
+     */
+    function lazyValue() {
+      var array = this.__wrapped__.value(),
+          dir = this.__dir__,
+          isArr = isArray(array),
+          isRight = dir < 0,
+          arrLength = isArr ? array.length : 0,
+          view = getView(0, arrLength, this.__views__),
+          start = view.start,
+          end = view.end,
+          length = end - start,
+          index = isRight ? end : (start - 1),
+          iteratees = this.__iteratees__,
+          iterLength = iteratees.length,
+          resIndex = 0,
+          takeCount = nativeMin(length, this.__takeCount__);
+
+      if (!isArr || arrLength < LARGE_ARRAY_SIZE || (arrLength == length && takeCount == length)) {
+        return baseWrapperValue(array, this.__actions__);
+      }
+      var result = [];
+
+      outer:
+      while (length-- && resIndex < takeCount) {
+        index += dir;
+
+        var iterIndex = -1,
+            value = array[index];
+
+        while (++iterIndex < iterLength) {
+          var data = iteratees[iterIndex],
+              iteratee = data.iteratee,
+              type = data.type,
+              computed = iteratee(value);
+
+          if (type == LAZY_MAP_FLAG) {
+            value = computed;
+          } else if (!computed) {
+            if (type == LAZY_FILTER_FLAG) {
+              continue outer;
+            } else {
+              break outer;
+            }
+          }
+        }
+        result[resIndex++] = value;
+      }
+      return result;
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a cache object to store key/value pairs.
+     *
+     * @private
+     * @static
+     * @name Cache
+     * @memberOf _.memoize
+     */
+    function MapCache() {
+      this.__data__ = {};
+    }
+
+    /**
+     * Removes `key` and its value from the cache.
+     *
+     * @private
+     * @name delete
+     * @memberOf _.memoize.Cache
+     * @param {string} key The key of the value to remove.
+     * @returns {boolean} Returns `true` if the entry was removed successfully, else `false`.
+     */
+    function mapDelete(key) {
+      return this.has(key) && delete this.__data__[key];
+    }
+
+    /**
+     * Gets the cached value for `key`.
+     *
+     * @private
+     * @name get
+     * @memberOf _.memoize.Cache
+     * @param {string} key The key of the value to get.
+     * @returns {*} Returns the cached value.
+     */
+    function mapGet(key) {
+      return key == '__proto__' ? undefined : this.__data__[key];
+    }
+
+    /**
+     * Checks if a cached value for `key` exists.
+     *
+     * @private
+     * @name has
+     * @memberOf _.memoize.Cache
+     * @param {string} key The key of the entry to check.
+     * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
+     */
+    function mapHas(key) {
+      return key != '__proto__' && hasOwnProperty.call(this.__data__, key);
+    }
+
+    /**
+     * Sets `value` to `key` of the cache.
+     *
+     * @private
+     * @name set
+     * @memberOf _.memoize.Cache
+     * @param {string} key The key of the value to cache.
+     * @param {*} value The value to cache.
+     * @returns {Object} Returns the cache object.
+     */
+    function mapSet(key, value) {
+      if (key != '__proto__') {
+        this.__data__[key] = value;
+      }
+      return this;
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     *
+     * Creates a cache object to store unique values.
+     *
+     * @private
+     * @param {Array} [values] The values to cache.
+     */
+    function SetCache(values) {
+      var length = values ? values.length : 0;
+
+      this.data = { 'hash': nativeCreate(null), 'set': new Set };
+      while (length--) {
+        this.push(values[length]);
+      }
+    }
+
+    /**
+     * Checks if `value` is in `cache` mimicking the return signature of
+     * `_.indexOf` by returning `0` if the value is found, else `-1`.
+     *
+     * @private
+     * @param {Object} cache The cache to search.
+     * @param {*} value The value to search for.
+     * @returns {number} Returns `0` if `value` is found, else `-1`.
+     */
+    function cacheIndexOf(cache, value) {
+      var data = cache.data,
+          result = (typeof value == 'string' || isObject(value)) ? data.set.has(value) : data.hash[value];
+
+      return result ? 0 : -1;
+    }
+
+    /**
+     * Adds `value` to the cache.
+     *
+     * @private
+     * @name push
+     * @memberOf SetCache
+     * @param {*} value The value to cache.
+     */
+    function cachePush(value) {
+      var data = this.data;
+      if (typeof value == 'string' || isObject(value)) {
+        data.set.add(value);
+      } else {
+        data.hash[value] = true;
+      }
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a new array joining `array` with `other`.
+     *
+     * @private
+     * @param {Array} array The array to join.
+     * @param {Array} other The other array to join.
+     * @returns {Array} Returns the new concatenated array.
+     */
+    function arrayConcat(array, other) {
+      var index = -1,
+          length = array.length,
+          othIndex = -1,
+          othLength = other.length,
+          result = Array(length + othLength);
+
+      while (++index < length) {
+        result[index] = array[index];
+      }
+      while (++othIndex < othLength) {
+        result[index++] = other[othIndex];
+      }
+      return result;
+    }
+
+    /**
+     * Copies the values of `source` to `array`.
+     *
+     * @private
+     * @param {Array} source The array to copy values from.
+     * @param {Array} [array=[]] The array to copy values to.
+     * @returns {Array} Returns `array`.
+     */
+    function arrayCopy(source, array) {
+      var index = -1,
+          length = source.length;
+
+      array || (array = Array(length));
+      while (++index < length) {
+        array[index] = source[index];
+      }
+      return array;
+    }
+
+    /**
+     * A specialized version of `_.forEach` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array} Returns `array`.
+     */
+    function arrayEach(array, iteratee) {
+      var index = -1,
+          length = array.length;
+
+      while (++index < length) {
+        if (iteratee(array[index], index, array) === false) {
+          break;
+        }
+      }
+      return array;
+    }
+
+    /**
+     * A specialized version of `_.forEachRight` for arrays without support for
+     * callback shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array} Returns `array`.
+     */
+    function arrayEachRight(array, iteratee) {
+      var length = array.length;
+
+      while (length--) {
+        if (iteratee(array[length], length, array) === false) {
+          break;
+        }
+      }
+      return array;
+    }
+
+    /**
+     * A specialized version of `_.every` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {boolean} Returns `true` if all elements pass the predicate check,
+     *  else `false`.
+     */
+    function arrayEvery(array, predicate) {
+      var index = -1,
+          length = array.length;
+
+      while (++index < length) {
+        if (!predicate(array[index], index, array)) {
+          return false;
+        }
+      }
+      return true;
+    }
+
+    /**
+     * A specialized version of `baseExtremum` for arrays which invokes `iteratee`
+     * with one argument: (value).
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {Function} comparator The function used to compare values.
+     * @param {*} exValue The initial extremum value.
+     * @returns {*} Returns the extremum value.
+     */
+    function arrayExtremum(array, iteratee, comparator, exValue) {
+      var index = -1,
+          length = array.length,
+          computed = exValue,
+          result = computed;
+
+      while (++index < length) {
+        var value = array[index],
+            current = +iteratee(value);
+
+        if (comparator(current, computed)) {
+          computed = current;
+          result = value;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * A specialized version of `_.filter` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {Array} Returns the new filtered array.
+     */
+    function arrayFilter(array, predicate) {
+      var index = -1,
+          length = array.length,
+          resIndex = -1,
+          result = [];
+
+      while (++index < length) {
+        var value = array[index];
+        if (predicate(value, index, array)) {
+          result[++resIndex] = value;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * A specialized version of `_.map` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array} Returns the new mapped array.
+     */
+    function arrayMap(array, iteratee) {
+      var index = -1,
+          length = array.length,
+          result = Array(length);
+
+      while (++index < length) {
+        result[index] = iteratee(array[index], index, array);
+      }
+      return result;
+    }
+
+    /**
+     * Appends the elements of `values` to `array`.
+     *
+     * @private
+     * @param {Array} array The array to modify.
+     * @param {Array} values The values to append.
+     * @returns {Array} Returns `array`.
+     */
+    function arrayPush(array, values) {
+      var index = -1,
+          length = values.length,
+          offset = array.length;
+
+      while (++index < length) {
+        array[offset + index] = values[index];
+      }
+      return array;
+    }
+
+    /**
+     * A specialized version of `_.reduce` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {*} [accumulator] The initial value.
+     * @param {boolean} [initFromArray] Specify using the first element of `array`
+     *  as the initial value.
+     * @returns {*} Returns the accumulated value.
+     */
+    function arrayReduce(array, iteratee, accumulator, initFromArray) {
+      var index = -1,
+          length = array.length;
+
+      if (initFromArray && length) {
+        accumulator = array[++index];
+      }
+      while (++index < length) {
+        accumulator = iteratee(accumulator, array[index], index, array);
+      }
+      return accumulator;
+    }
+
+    /**
+     * A specialized version of `_.reduceRight` for arrays without support for
+     * callback shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {*} [accumulator] The initial value.
+     * @param {boolean} [initFromArray] Specify using the last element of `array`
+     *  as the initial value.
+     * @returns {*} Returns the accumulated value.
+     */
+    function arrayReduceRight(array, iteratee, accumulator, initFromArray) {
+      var length = array.length;
+      if (initFromArray && length) {
+        accumulator = array[--length];
+      }
+      while (length--) {
+        accumulator = iteratee(accumulator, array[length], length, array);
+      }
+      return accumulator;
+    }
+
+    /**
+     * A specialized version of `_.some` for arrays without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {boolean} Returns `true` if any element passes the predicate check,
+     *  else `false`.
+     */
+    function arraySome(array, predicate) {
+      var index = -1,
+          length = array.length;
+
+      while (++index < length) {
+        if (predicate(array[index], index, array)) {
+          return true;
+        }
+      }
+      return false;
+    }
+
+    /**
+     * A specialized version of `_.sum` for arrays without support for callback
+     * shorthands and `this` binding..
+     *
+     * @private
+     * @param {Array} array The array to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {number} Returns the sum.
+     */
+    function arraySum(array, iteratee) {
+      var length = array.length,
+          result = 0;
+
+      while (length--) {
+        result += +iteratee(array[length]) || 0;
+      }
+      return result;
+    }
+
+    /**
+     * Used by `_.defaults` to customize its `_.assign` use.
+     *
+     * @private
+     * @param {*} objectValue The destination object property value.
+     * @param {*} sourceValue The source object property value.
+     * @returns {*} Returns the value to assign to the destination object.
+     */
+    function assignDefaults(objectValue, sourceValue) {
+      return objectValue === undefined ? sourceValue : objectValue;
+    }
+
+    /**
+     * Used by `_.template` to customize its `_.assign` use.
+     *
+     * **Note:** This function is like `assignDefaults` except that it ignores
+     * inherited property values when checking if a property is `undefined`.
+     *
+     * @private
+     * @param {*} objectValue The destination object property value.
+     * @param {*} sourceValue The source object property value.
+     * @param {string} key The key associated with the object and source values.
+     * @param {Object} object The destination object.
+     * @returns {*} Returns the value to assign to the destination object.
+     */
+    function assignOwnDefaults(objectValue, sourceValue, key, object) {
+      return (objectValue === undefined || !hasOwnProperty.call(object, key))
+        ? sourceValue
+        : objectValue;
+    }
+
+    /**
+     * A specialized version of `_.assign` for customizing assigned values without
+     * support for argument juggling, multiple sources, and `this` binding `customizer`
+     * functions.
+     *
+     * @private
+     * @param {Object} object The destination object.
+     * @param {Object} source The source object.
+     * @param {Function} customizer The function to customize assigned values.
+     * @returns {Object} Returns `object`.
+     */
+    function assignWith(object, source, customizer) {
+      var index = -1,
+          props = keys(source),
+          length = props.length;
+
+      while (++index < length) {
+        var key = props[index],
+            value = object[key],
+            result = customizer(value, source[key], key, object, source);
+
+        if ((result === result ? (result !== value) : (value === value)) ||
+            (value === undefined && !(key in object))) {
+          object[key] = result;
+        }
+      }
+      return object;
+    }
+
+    /**
+     * The base implementation of `_.assign` without support for argument juggling,
+     * multiple sources, and `customizer` functions.
+     *
+     * @private
+     * @param {Object} object The destination object.
+     * @param {Object} source The source object.
+     * @returns {Object} Returns `object`.
+     */
+    function baseAssign(object, source) {
+      return source == null
+        ? object
+        : baseCopy(source, keys(source), object);
+    }
+
+    /**
+     * The base implementation of `_.at` without support for string collections
+     * and individual key arguments.
+     *
+     * @private
+     * @param {Array|Object} collection The collection to iterate over.
+     * @param {number[]|string[]} props The property names or indexes of elements to pick.
+     * @returns {Array} Returns the new array of picked elements.
+     */
+    function baseAt(collection, props) {
+      var index = -1,
+          isNil = collection == null,
+          isArr = !isNil && isArrayLike(collection),
+          length = isArr ? collection.length : 0,
+          propsLength = props.length,
+          result = Array(propsLength);
+
+      while(++index < propsLength) {
+        var key = props[index];
+        if (isArr) {
+          result[index] = isIndex(key, length) ? collection[key] : undefined;
+        } else {
+          result[index] = isNil ? undefined : collection[key];
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Copies properties of `source` to `object`.
+     *
+     * @private
+     * @param {Object} source The object to copy properties from.
+     * @param {Array} props The property names to copy.
+     * @param {Object} [object={}] The object to copy properties to.
+     * @returns {Object} Returns `object`.
+     */
+    function baseCopy(source, props, object) {
+      object || (object = {});
+
+      var index = -1,
+          length = props.length;
+
+      while (++index < length) {
+        var key = props[index];
+        object[key] = source[key];
+      }
+      return object;
+    }
+
+    /**
+     * The base implementation of `_.callback` which supports specifying the
+     * number of arguments to provide to `func`.
+     *
+     * @private
+     * @param {*} [func=_.identity] The value to convert to a callback.
+     * @param {*} [thisArg] The `this` binding of `func`.
+     * @param {number} [argCount] The number of arguments to provide to `func`.
+     * @returns {Function} Returns the callback.
+     */
+    function baseCallback(func, thisArg, argCount) {
+      var type = typeof func;
+      if (type == 'function') {
+        return thisArg === undefined
+          ? func
+          : bindCallback(func, thisArg, argCount);
+      }
+      if (func == null) {
+        return identity;
+      }
+      if (type == 'object') {
+        return baseMatches(func);
+      }
+      return thisArg === undefined
+        ? property(func)
+        : baseMatchesProperty(func, thisArg);
+    }
+
+    /**
+     * The base implementation of `_.clone` without support for argument juggling
+     * and `this` binding `customizer` functions.
      *
      * @private
      * @param {*} value The value to clone.
-     * @param {boolean} [isDeep=false] Specify a deep clone.
-     * @param {Function} [callback] The function to customize cloning values.
+     * @param {boolean} [isDeep] Specify a deep clone.
+     * @param {Function} [customizer] The function to customize cloning values.
+     * @param {string} [key] The key of `value`.
+     * @param {Object} [object] The object `value` belongs to.
      * @param {Array} [stackA=[]] Tracks traversed source objects.
      * @param {Array} [stackB=[]] Associates clones with source counterparts.
      * @returns {*} Returns the cloned value.
      */
-    function baseClone(value, isDeep, callback, stackA, stackB) {
-      if (callback) {
-        var result = callback(value);
-        if (typeof result != 'undefined') {
-          return result;
-        }
-      }
-      // inspect [[Class]]
-      var isObj = isObject(value);
-      if (isObj) {
-        var className = toString.call(value);
-        if (!cloneableClasses[className]) {
-          return value;
-        }
-        var ctor = ctorByClass[className];
-        switch (className) {
-          case boolClass:
-          case dateClass:
-            return new ctor(+value);
-
-          case numberClass:
-          case stringClass:
-            return new ctor(value);
-
-          case regexpClass:
-            result = ctor(value.source, reFlags.exec(value));
-            result.lastIndex = value.lastIndex;
-            return result;
-        }
-      } else {
+    function baseClone(value, isDeep, customizer, key, object, stackA, stackB) {
+      var result;
+      if (customizer) {
+        result = object ? customizer(value, key, object) : customizer(value);
+      }
+      if (result !== undefined) {
+        return result;
+      }
+      if (!isObject(value)) {
         return value;
       }
       var isArr = isArray(value);
-      if (isDeep) {
-        // check for circular references and return corresponding clone
-        var initedStack = !stackA;
-        stackA || (stackA = getArray());
-        stackB || (stackB = getArray());
-
-        var length = stackA.length;
-        while (length--) {
-          if (stackA[length] == value) {
-            return stackB[length];
+      if (isArr) {
+        result = initCloneArray(value);
+        if (!isDeep) {
+          return arrayCopy(value, result);
+        }
+      } else {
+        var tag = objToString.call(value),
+            isFunc = tag == funcTag;
+
+        if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
+          result = initCloneObject(isFunc ? {} : value);
+          if (!isDeep) {
+            return baseAssign(result, value);
           }
-        }
-        result = isArr ? ctor(value.length) : {};
-      }
-      else {
-        result = isArr ? slice(value) : assign({}, value);
-      }
-      // add array properties assigned by `RegExp#exec`
-      if (isArr) {
-        if (hasOwnProperty.call(value, 'index')) {
-          result.index = value.index;
-        }
-        if (hasOwnProperty.call(value, 'input')) {
-          result.input = value.input;
-        }
-      }
-      // exit for shallow clone
-      if (!isDeep) {
-        return result;
-      }
-      // add the source value to the stack of traversed objects
-      // and associate it with its clone
+        } else {
+          return cloneableTags[tag]
+            ? initCloneByTag(value, tag, isDeep)
+            : (object ? value : {});
+        }
+      }
+      // Check for circular references and return its corresponding clone.
+      stackA || (stackA = []);
+      stackB || (stackB = []);
+
+      var length = stackA.length;
+      while (length--) {
+        if (stackA[length] == value) {
+          return stackB[length];
+        }
+      }
+      // Add the source value to the stack of traversed objects and associate it with its clone.
       stackA.push(value);
       stackB.push(result);
 
-      // recursively populate clone (susceptible to call stack limits)
-      (isArr ? forEach : forOwn)(value, function(objValue, key) {
-        result[key] = baseClone(objValue, isDeep, callback, stackA, stackB);
+      // Recursively populate clone (susceptible to call stack limits).
+      (isArr ? arrayEach : baseForOwn)(value, function(subValue, key) {
+        result[key] = baseClone(subValue, isDeep, customizer, key, value, stackA, stackB);
       });
-
-      if (initedStack) {
-        releaseArray(stackA);
-        releaseArray(stackB);
-      }
       return result;
     }
 
@@ -832,537 +1744,1248 @@
      * @param {Object} prototype The object to inherit from.
      * @returns {Object} Returns the new object.
      */
-    function baseCreate(prototype, properties) {
-      return isObject(prototype) ? nativeCreate(prototype) : {};
-    }
-    // fallback for browsers without `Object.create`
-    if (!nativeCreate) {
-      baseCreate = (function() {
-        function Object() {}
-        return function(prototype) {
-          if (isObject(prototype)) {
-            Object.prototype = prototype;
-            var result = new Object;
-            Object.prototype = null;
+    var baseCreate = (function() {
+      function object() {}
+      return function(prototype) {
+        if (isObject(prototype)) {
+          object.prototype = prototype;
+          var result = new object;
+          object.prototype = undefined;
+        }
+        return result || {};
+      };
+    }());
+
+    /**
+     * The base implementation of `_.delay` and `_.defer` which accepts an index
+     * of where to slice the arguments to provide to `func`.
+     *
+     * @private
+     * @param {Function} func The function to delay.
+     * @param {number} wait The number of milliseconds to delay invocation.
+     * @param {Object} args The arguments provide to `func`.
+     * @returns {number} Returns the timer id.
+     */
+    function baseDelay(func, wait, args) {
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      return setTimeout(function() { func.apply(undefined, args); }, wait);
+    }
+
+    /**
+     * The base implementation of `_.difference` which accepts a single array
+     * of values to exclude.
+     *
+     * @private
+     * @param {Array} array The array to inspect.
+     * @param {Array} values The values to exclude.
+     * @returns {Array} Returns the new array of filtered values.
+     */
+    function baseDifference(array, values) {
+      var length = array ? array.length : 0,
+          result = [];
+
+      if (!length) {
+        return result;
+      }
+      var index = -1,
+          indexOf = getIndexOf(),
+          isCommon = indexOf === baseIndexOf,
+          cache = (isCommon && values.length >= LARGE_ARRAY_SIZE) ? createCache(values) : null,
+          valuesLength = values.length;
+
+      if (cache) {
+        indexOf = cacheIndexOf;
+        isCommon = false;
+        values = cache;
+      }
+      outer:
+      while (++index < length) {
+        var value = array[index];
+
+        if (isCommon && value === value) {
+          var valuesIndex = valuesLength;
+          while (valuesIndex--) {
+            if (values[valuesIndex] === value) {
+              continue outer;
+            }
+          }
+          result.push(value);
+        }
+        else if (indexOf(values, value, 0) < 0) {
+          result.push(value);
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.forEach` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array|Object|string} Returns `collection`.
+     */
+    var baseEach = createBaseEach(baseForOwn);
+
+    /**
+     * The base implementation of `_.forEachRight` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array|Object|string} Returns `collection`.
+     */
+    var baseEachRight = createBaseEach(baseForOwnRight, true);
+
+    /**
+     * The base implementation of `_.every` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {boolean} Returns `true` if all elements pass the predicate check,
+     *  else `false`
+     */
+    function baseEvery(collection, predicate) {
+      var result = true;
+      baseEach(collection, function(value, index, collection) {
+        result = !!predicate(value, index, collection);
+        return result;
+      });
+      return result;
+    }
+
+    /**
+     * Gets the extremum value of `collection` invoking `iteratee` for each value
+     * in `collection` to generate the criterion by which the value is ranked.
+     * The `iteratee` is invoked with three arguments: (value, index|key, collection).
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {Function} comparator The function used to compare values.
+     * @param {*} exValue The initial extremum value.
+     * @returns {*} Returns the extremum value.
+     */
+    function baseExtremum(collection, iteratee, comparator, exValue) {
+      var computed = exValue,
+          result = computed;
+
+      baseEach(collection, function(value, index, collection) {
+        var current = +iteratee(value, index, collection);
+        if (comparator(current, computed) || (current === exValue && current === result)) {
+          computed = current;
+          result = value;
+        }
+      });
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.fill` without an iteratee call guard.
+     *
+     * @private
+     * @param {Array} array The array to fill.
+     * @param {*} value The value to fill `array` with.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns `array`.
+     */
+    function baseFill(array, value, start, end) {
+      var length = array.length;
+
+      start = start == null ? 0 : (+start || 0);
+      if (start < 0) {
+        start = -start > length ? 0 : (length + start);
+      }
+      end = (end === undefined || end > length) ? length : (+end || 0);
+      if (end < 0) {
+        end += length;
+      }
+      length = start > end ? 0 : (end >>> 0);
+      start >>>= 0;
+
+      while (start < length) {
+        array[start++] = value;
+      }
+      return array;
+    }
+
+    /**
+     * The base implementation of `_.filter` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {Array} Returns the new filtered array.
+     */
+    function baseFilter(collection, predicate) {
+      var result = [];
+      baseEach(collection, function(value, index, collection) {
+        if (predicate(value, index, collection)) {
+          result.push(value);
+        }
+      });
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.find`, `_.findLast`, `_.findKey`, and `_.findLastKey`,
+     * without support for callback shorthands and `this` binding, which iterates
+     * over `collection` using the provided `eachFunc`.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {Function} predicate The function invoked per iteration.
+     * @param {Function} eachFunc The function to iterate over `collection`.
+     * @param {boolean} [retKey] Specify returning the key of the found element
+     *  instead of the element itself.
+     * @returns {*} Returns the found element or its key, else `undefined`.
+     */
+    function baseFind(collection, predicate, eachFunc, retKey) {
+      var result;
+      eachFunc(collection, function(value, key, collection) {
+        if (predicate(value, key, collection)) {
+          result = retKey ? key : value;
+          return false;
+        }
+      });
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.flatten` with added support for restricting
+     * flattening and specifying the start index.
+     *
+     * @private
+     * @param {Array} array The array to flatten.
+     * @param {boolean} [isDeep] Specify a deep flatten.
+     * @param {boolean} [isStrict] Restrict flattening to arrays-like objects.
+     * @param {Array} [result=[]] The initial result value.
+     * @returns {Array} Returns the new flattened array.
+     */
+    function baseFlatten(array, isDeep, isStrict, result) {
+      result || (result = []);
+
+      var index = -1,
+          length = array.length;
+
+      while (++index < length) {
+        var value = array[index];
+        if (isObjectLike(value) && isArrayLike(value) &&
+            (isStrict || isArray(value) || isArguments(value))) {
+          if (isDeep) {
+            // Recursively flatten arrays (susceptible to call stack limits).
+            baseFlatten(value, isDeep, isStrict, result);
+          } else {
+            arrayPush(result, value);
           }
-          return result || context.Object();
+        } else if (!isStrict) {
+          result[result.length] = value;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `baseForIn` and `baseForOwn` which iterates
+     * over `object` properties returned by `keysFunc` invoking `iteratee` for
+     * each property. Iteratee functions may exit iteration early by explicitly
+     * returning `false`.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {Function} keysFunc The function to get the keys of `object`.
+     * @returns {Object} Returns `object`.
+     */
+    var baseFor = createBaseFor();
+
+    /**
+     * This function is like `baseFor` except that it iterates over properties
+     * in the opposite order.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {Function} keysFunc The function to get the keys of `object`.
+     * @returns {Object} Returns `object`.
+     */
+    var baseForRight = createBaseFor(true);
+
+    /**
+     * The base implementation of `_.forIn` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     */
+    function baseForIn(object, iteratee) {
+      return baseFor(object, iteratee, keysIn);
+    }
+
+    /**
+     * The base implementation of `_.forOwn` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     */
+    function baseForOwn(object, iteratee) {
+      return baseFor(object, iteratee, keys);
+    }
+
+    /**
+     * The base implementation of `_.forOwnRight` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Object} object The object to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Object} Returns `object`.
+     */
+    function baseForOwnRight(object, iteratee) {
+      return baseForRight(object, iteratee, keys);
+    }
+
+    /**
+     * The base implementation of `_.functions` which creates an array of
+     * `object` function property names filtered from those provided.
+     *
+     * @private
+     * @param {Object} object The object to inspect.
+     * @param {Array} props The property names to filter.
+     * @returns {Array} Returns the new array of filtered property names.
+     */
+    function baseFunctions(object, props) {
+      var index = -1,
+          length = props.length,
+          resIndex = -1,
+          result = [];
+
+      while (++index < length) {
+        var key = props[index];
+        if (isFunction(object[key])) {
+          result[++resIndex] = key;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `get` without support for string paths
+     * and default values.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Array} path The path of the property to get.
+     * @param {string} [pathKey] The key representation of path.
+     * @returns {*} Returns the resolved value.
+     */
+    function baseGet(object, path, pathKey) {
+      if (object == null) {
+        return;
+      }
+      if (pathKey !== undefined && pathKey in toObject(object)) {
+        path = [pathKey];
+      }
+      var index = 0,
+          length = path.length;
+
+      while (object != null && index < length) {
+        object = object[path[index++]];
+      }
+      return (index && index == length) ? object : undefined;
+    }
+
+    /**
+     * The base implementation of `_.isEqual` without support for `this` binding
+     * `customizer` functions.
+     *
+     * @private
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @param {Function} [customizer] The function to customize comparing values.
+     * @param {boolean} [isLoose] Specify performing partial comparisons.
+     * @param {Array} [stackA] Tracks traversed `value` objects.
+     * @param {Array} [stackB] Tracks traversed `other` objects.
+     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
+     */
+    function baseIsEqual(value, other, customizer, isLoose, stackA, stackB) {
+      if (value === other) {
+        return true;
+      }
+      if (value == null || other == null || (!isObject(value) && !isObjectLike(other))) {
+        return value !== value && other !== other;
+      }
+      return baseIsEqualDeep(value, other, baseIsEqual, customizer, isLoose, stackA, stackB);
+    }
+
+    /**
+     * A specialized version of `baseIsEqual` for arrays and objects which performs
+     * deep comparisons and tracks traversed objects enabling objects with circular
+     * references to be compared.
+     *
+     * @private
+     * @param {Object} object The object to compare.
+     * @param {Object} other The other object to compare.
+     * @param {Function} equalFunc The function to determine equivalents of values.
+     * @param {Function} [customizer] The function to customize comparing objects.
+     * @param {boolean} [isLoose] Specify performing partial comparisons.
+     * @param {Array} [stackA=[]] Tracks traversed `value` objects.
+     * @param {Array} [stackB=[]] Tracks traversed `other` objects.
+     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
+     */
+    function baseIsEqualDeep(object, other, equalFunc, customizer, isLoose, stackA, stackB) {
+      var objIsArr = isArray(object),
+          othIsArr = isArray(other),
+          objTag = arrayTag,
+          othTag = arrayTag;
+
+      if (!objIsArr) {
+        objTag = objToString.call(object);
+        if (objTag == argsTag) {
+          objTag = objectTag;
+        } else if (objTag != objectTag) {
+          objIsArr = isTypedArray(object);
+        }
+      }
+      if (!othIsArr) {
+        othTag = objToString.call(other);
+        if (othTag == argsTag) {
+          othTag = objectTag;
+        } else if (othTag != objectTag) {
+          othIsArr = isTypedArray(other);
+        }
+      }
+      var objIsObj = objTag == objectTag,
+          othIsObj = othTag == objectTag,
+          isSameTag = objTag == othTag;
+
+      if (isSameTag && !(objIsArr || objIsObj)) {
+        return equalByTag(object, other, objTag);
+      }
+      if (!isLoose) {
+        var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
+            othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');
+
+        if (objIsWrapped || othIsWrapped) {
+          return equalFunc(objIsWrapped ? object.value() : object, othIsWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
+        }
+      }
+      if (!isSameTag) {
+        return false;
+      }
+      // Assume cyclic values are equal.
+      // For more information on detecting circular references see https://es5.github.io/#JO.
+      stackA || (stackA = []);
+      stackB || (stackB = []);
+
+      var length = stackA.length;
+      while (length--) {
+        if (stackA[length] == object) {
+          return stackB[length] == other;
+        }
+      }
+      // Add `object` and `other` to the stack of traversed objects.
+      stackA.push(object);
+      stackB.push(other);
+
+      var result = (objIsArr ? equalArrays : equalObjects)(object, other, equalFunc, customizer, isLoose, stackA, stackB);
+
+      stackA.pop();
+      stackB.pop();
+
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.isMatch` without support for callback
+     * shorthands and `this` binding.
+     *
+     * @private
+     * @param {Object} object The object to inspect.
+     * @param {Array} matchData The propery names, values, and compare flags to match.
+     * @param {Function} [customizer] The function to customize comparing objects.
+     * @returns {boolean} Returns `true` if `object` is a match, else `false`.
+     */
+    function baseIsMatch(object, matchData, customizer) {
+      var index = matchData.length,
+          length = index,
+          noCustomizer = !customizer;
+
+      if (object == null) {
+        return !length;
+      }
+      object = toObject(object);
+      while (index--) {
+        var data = matchData[index];
+        if ((noCustomizer && data[2])
+              ? data[1] !== object[data[0]]
+              : !(data[0] in object)
+            ) {
+          return false;
+        }
+      }
+      while (++index < length) {
+        data = matchData[index];
+        var key = data[0],
+            objValue = object[key],
+            srcValue = data[1];
+
+        if (noCustomizer && data[2]) {
+          if (objValue === undefined && !(key in object)) {
+            return false;
+          }
+        } else {
+          var result = customizer ? customizer(objValue, srcValue, key) : undefined;
+          if (!(result === undefined ? baseIsEqual(srcValue, objValue, customizer, true) : result)) {
+            return false;
+          }
+        }
+      }
+      return true;
+    }
+
+    /**
+     * The base implementation of `_.map` without support for callback shorthands
+     * and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {Array} Returns the new mapped array.
+     */
+    function baseMap(collection, iteratee) {
+      var index = -1,
+          result = isArrayLike(collection) ? Array(collection.length) : [];
+
+      baseEach(collection, function(value, key, collection) {
+        result[++index] = iteratee(value, key, collection);
+      });
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.matches` which does not clone `source`.
+     *
+     * @private
+     * @param {Object} source The object of property values to match.
+     * @returns {Function} Returns the new function.
+     */
+    function baseMatches(source) {
+      var matchData = getMatchData(source);
+      if (matchData.length == 1 && matchData[0][2]) {
+        var key = matchData[0][0],
+            value = matchData[0][1];
+
+        return function(object) {
+          if (object == null) {
+            return false;
+          }
+          return object[key] === value && (value !== undefined || (key in toObject(object)));
         };
-      }());
-    }
-
-    /**
-     * The base implementation of `_.createCallback` without support for creating
-     * "_.pluck" or "_.where" style callbacks.
-     *
-     * @private
-     * @param {*} [func=identity] The value to convert to a callback.
-     * @param {*} [thisArg] The `this` binding of the created callback.
-     * @param {number} [argCount] The number of arguments the callback accepts.
-     * @returns {Function} Returns a callback function.
-     */
-    function baseCreateCallback(func, thisArg, argCount) {
+      }
+      return function(object) {
+        return baseIsMatch(object, matchData);
+      };
+    }
+
+    /**
+     * The base implementation of `_.matchesProperty` which does not clone `srcValue`.
+     *
+     * @private
+     * @param {string} path The path of the property to get.
+     * @param {*} srcValue The value to compare.
+     * @returns {Function} Returns the new function.
+     */
+    function baseMatchesProperty(path, srcValue) {
+      var isArr = isArray(path),
+          isCommon = isKey(path) && isStrictComparable(srcValue),
+          pathKey = (path + '');
+
+      path = toPath(path);
+      return function(object) {
+        if (object == null) {
+          return false;
+        }
+        var key = pathKey;
+        object = toObject(object);
+        if ((isArr || !isCommon) && !(key in object)) {
+          object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+          if (object == null) {
+            return false;
+          }
+          key = last(path);
+          object = toObject(object);
+        }
+        return object[key] === srcValue
+          ? (srcValue !== undefined || (key in object))
+          : baseIsEqual(srcValue, object[key], undefined, true);
+      };
+    }
+
+    /**
+     * The base implementation of `_.merge` without support for argument juggling,
+     * multiple sources, and `this` binding `customizer` functions.
+     *
+     * @private
+     * @param {Object} object The destination object.
+     * @param {Object} source The source object.
+     * @param {Function} [customizer] The function to customize merged values.
+     * @param {Array} [stackA=[]] Tracks traversed source objects.
+     * @param {Array} [stackB=[]] Associates values with source counterparts.
+     * @returns {Object} Returns `object`.
+     */
+    function baseMerge(object, source, customizer, stackA, stackB) {
+      if (!isObject(object)) {
+        return object;
+      }
+      var isSrcArr = isArrayLike(source) && (isArray(source) || isTypedArray(source)),
+          props = isSrcArr ? undefined : keys(source);
+
+      arrayEach(props || source, function(srcValue, key) {
+        if (props) {
+          key = srcValue;
+          srcValue = source[key];
+        }
+        if (isObjectLike(srcValue)) {
+          stackA || (stackA = []);
+          stackB || (stackB = []);
+          baseMergeDeep(object, source, key, baseMerge, customizer, stackA, stackB);
+        }
+        else {
+          var value = object[key],
+              result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
+              isCommon = result === undefined;
+
+          if (isCommon) {
+            result = srcValue;
+          }
+          if ((result !== undefined || (isSrcArr && !(key in object))) &&
+              (isCommon || (result === result ? (result !== value) : (value === value)))) {
+            object[key] = result;
+          }
+        }
+      });
+      return object;
+    }
+
+    /**
+     * A specialized version of `baseMerge` for arrays and objects which performs
+     * deep merges and tracks traversed objects enabling objects with circular
+     * references to be merged.
+     *
+     * @private
+     * @param {Object} object The destination object.
+     * @param {Object} source The source object.
+     * @param {string} key The key of the value to merge.
+     * @param {Function} mergeFunc The function to merge values.
+     * @param {Function} [customizer] The function to customize merged values.
+     * @param {Array} [stackA=[]] Tracks traversed source objects.
+     * @param {Array} [stackB=[]] Associates values with source counterparts.
+     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
+     */
+    function baseMergeDeep(object, source, key, mergeFunc, customizer, stackA, stackB) {
+      var length = stackA.length,
+          srcValue = source[key];
+
+      while (length--) {
+        if (stackA[length] == srcValue) {
+          object[key] = stackB[length];
+          return;
+        }
+      }
+      var value = object[key],
+          result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
+          isCommon = result === undefined;
+
+      if (isCommon) {
+        result = srcValue;
+        if (isArrayLike(srcValue) && (isArray(srcValue) || isTypedArray(srcValue))) {
+          result = isArray(value)
+            ? value
+            : (isArrayLike(value) ? arrayCopy(value) : []);
+        }
+        else if (isPlainObject(srcValue) || isArguments(srcValue)) {
+          result = isArguments(value)
+            ? toPlainObject(value)
+            : (isPlainObject(value) ? value : {});
+        }
+        else {
+          isCommon = false;
+        }
+      }
+      // Add the source value to the stack of traversed objects and associate
+      // it with its merged value.
+      stackA.push(srcValue);
+      stackB.push(result);
+
+      if (isCommon) {
+        // Recursively merge objects and arrays (susceptible to call stack limits).
+        object[key] = mergeFunc(result, srcValue, customizer, stackA, stackB);
+      } else if (result === result ? (result !== value) : (value === value)) {
+        object[key] = result;
+      }
+    }
+
+    /**
+     * The base implementation of `_.property` without support for deep paths.
+     *
+     * @private
+     * @param {string} key The key of the property to get.
+     * @returns {Function} Returns the new function.
+     */
+    function baseProperty(key) {
+      return function(object) {
+        return object == null ? undefined : object[key];
+      };
+    }
+
+    /**
+     * A specialized version of `baseProperty` which supports deep paths.
+     *
+     * @private
+     * @param {Array|string} path The path of the property to get.
+     * @returns {Function} Returns the new function.
+     */
+    function basePropertyDeep(path) {
+      var pathKey = (path + '');
+      path = toPath(path);
+      return function(object) {
+        return baseGet(object, path, pathKey);
+      };
+    }
+
+    /**
+     * The base implementation of `_.pullAt` without support for individual
+     * index arguments and capturing the removed elements.
+     *
+     * @private
+     * @param {Array} array The array to modify.
+     * @param {number[]} indexes The indexes of elements to remove.
+     * @returns {Array} Returns `array`.
+     */
+    function basePullAt(array, indexes) {
+      var length = array ? indexes.length : 0;
+      while (length--) {
+        var index = indexes[length];
+        if (index != previous && isIndex(index)) {
+          var previous = index;
+          splice.call(array, index, 1);
+        }
+      }
+      return array;
+    }
+
+    /**
+     * The base implementation of `_.random` without support for argument juggling
+     * and returning floating-point numbers.
+     *
+     * @private
+     * @param {number} min The minimum possible value.
+     * @param {number} max The maximum possible value.
+     * @returns {number} Returns the random number.
+     */
+    function baseRandom(min, max) {
+      return min + nativeFloor(nativeRandom() * (max - min + 1));
+    }
+
+    /**
+     * The base implementation of `_.reduce` and `_.reduceRight` without support
+     * for callback shorthands and `this` binding, which iterates over `collection`
+     * using the provided `eachFunc`.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {*} accumulator The initial value.
+     * @param {boolean} initFromCollection Specify using the first or last element
+     *  of `collection` as the initial value.
+     * @param {Function} eachFunc The function to iterate over `collection`.
+     * @returns {*} Returns the accumulated value.
+     */
+    function baseReduce(collection, iteratee, accumulator, initFromCollection, eachFunc) {
+      eachFunc(collection, function(value, index, collection) {
+        accumulator = initFromCollection
+          ? (initFromCollection = false, value)
+          : iteratee(accumulator, value, index, collection);
+      });
+      return accumulator;
+    }
+
+    /**
+     * The base implementation of `setData` without support for hot loop detection.
+     *
+     * @private
+     * @param {Function} func The function to associate metadata with.
+     * @param {*} data The metadata.
+     * @returns {Function} Returns `func`.
+     */
+    var baseSetData = !metaMap ? identity : function(func, data) {
+      metaMap.set(func, data);
+      return func;
+    };
+
+    /**
+     * The base implementation of `_.slice` without an iteratee call guard.
+     *
+     * @private
+     * @param {Array} array The array to slice.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns the slice of `array`.
+     */
+    function baseSlice(array, start, end) {
+      var index = -1,
+          length = array.length;
+
+      start = start == null ? 0 : (+start || 0);
+      if (start < 0) {
+        start = -start > length ? 0 : (length + start);
+      }
+      end = (end === undefined || end > length) ? length : (+end || 0);
+      if (end < 0) {
+        end += length;
+      }
+      length = start > end ? 0 : ((end - start) >>> 0);
+      start >>>= 0;
+
+      var result = Array(length);
+      while (++index < length) {
+        result[index] = array[index + start];
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.some` without support for callback shorthands
+     * and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {boolean} Returns `true` if any element passes the predicate check,
+     *  else `false`.
+     */
+    function baseSome(collection, predicate) {
+      var result;
+
+      baseEach(collection, function(value, index, collection) {
+        result = predicate(value, index, collection);
+        return !result;
+      });
+      return !!result;
+    }
+
+    /**
+     * The base implementation of `_.sortBy` which uses `comparer` to define
+     * the sort order of `array` and replaces criteria objects with their
+     * corresponding values.
+     *
+     * @private
+     * @param {Array} array The array to sort.
+     * @param {Function} comparer The function to define sort order.
+     * @returns {Array} Returns `array`.
+     */
+    function baseSortBy(array, comparer) {
+      var length = array.length;
+
+      array.sort(comparer);
+      while (length--) {
+        array[length] = array[length].value;
+      }
+      return array;
+    }
+
+    /**
+     * The base implementation of `_.sortByOrder` without param guards.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
+     * @param {boolean[]} orders The sort orders of `iteratees`.
+     * @returns {Array} Returns the new sorted array.
+     */
+    function baseSortByOrder(collection, iteratees, orders) {
+      var callback = getCallback(),
+          index = -1;
+
+      iteratees = arrayMap(iteratees, function(iteratee) { return callback(iteratee); });
+
+      var result = baseMap(collection, function(value) {
+        var criteria = arrayMap(iteratees, function(iteratee) { return iteratee(value); });
+        return { 'criteria': criteria, 'index': ++index, 'value': value };
+      });
+
+      return baseSortBy(result, function(object, other) {
+        return compareMultiple(object, other, orders);
+      });
+    }
+
+    /**
+     * The base implementation of `_.sum` without support for callback shorthands
+     * and `this` binding.
+     *
+     * @private
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @returns {number} Returns the sum.
+     */
+    function baseSum(collection, iteratee) {
+      var result = 0;
+      baseEach(collection, function(value, index, collection) {
+        result += +iteratee(value, index, collection) || 0;
+      });
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.uniq` without support for callback shorthands
+     * and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to inspect.
+     * @param {Function} [iteratee] The function invoked per iteration.
+     * @returns {Array} Returns the new duplicate free array.
+     */
+    function baseUniq(array, iteratee) {
+      var index = -1,
+          indexOf = getIndexOf(),
+          length = array.length,
+          isCommon = indexOf === baseIndexOf,
+          isLarge = isCommon && length >= LARGE_ARRAY_SIZE,
+          seen = isLarge ? createCache() : null,
+          result = [];
+
+      if (seen) {
+        indexOf = cacheIndexOf;
+        isCommon = false;
+      } else {
+        isLarge = false;
+        seen = iteratee ? [] : result;
+      }
+      outer:
+      while (++index < length) {
+        var value = array[index],
+            computed = iteratee ? iteratee(value, index, array) : value;
+
+        if (isCommon && value === value) {
+          var seenIndex = seen.length;
+          while (seenIndex--) {
+            if (seen[seenIndex] === computed) {
+              continue outer;
+            }
+          }
+          if (iteratee) {
+            seen.push(computed);
+          }
+          result.push(value);
+        }
+        else if (indexOf(seen, computed, 0) < 0) {
+          if (iteratee || isLarge) {
+            seen.push(computed);
+          }
+          result.push(value);
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.values` and `_.valuesIn` which creates an
+     * array of `object` property values corresponding to the property names
+     * of `props`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Array} props The property names to get values for.
+     * @returns {Object} Returns the array of property values.
+     */
+    function baseValues(object, props) {
+      var index = -1,
+          length = props.length,
+          result = Array(length);
+
+      while (++index < length) {
+        result[index] = object[props[index]];
+      }
+      return result;
+    }
+
+    /**
+     * The base implementation of `_.dropRightWhile`, `_.dropWhile`, `_.takeRightWhile`,
+     * and `_.takeWhile` without support for callback shorthands and `this` binding.
+     *
+     * @private
+     * @param {Array} array The array to query.
+     * @param {Function} predicate The function invoked per iteration.
+     * @param {boolean} [isDrop] Specify dropping elements instead of taking them.
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Array} Returns the slice of `array`.
+     */
+    function baseWhile(array, predicate, isDrop, fromRight) {
+      var length = array.length,
+          index = fromRight ? length : -1;
+
+      while ((fromRight ? index-- : ++index < length) && predicate(array[index], index, array)) {}
+      return isDrop
+        ? baseSlice(array, (fromRight ? 0 : index), (fromRight ? index + 1 : length))
+        : baseSlice(array, (fromRight ? index + 1 : 0), (fromRight ? length : index));
+    }
+
+    /**
+     * The base implementation of `wrapperValue` which returns the result of
+     * performing a sequence of actions on the unwrapped `value`, where each
+     * successive action is supplied the return value of the previous.
+     *
+     * @private
+     * @param {*} value The unwrapped value.
+     * @param {Array} actions Actions to peform to resolve the unwrapped value.
+     * @returns {*} Returns the resolved value.
+     */
+    function baseWrapperValue(value, actions) {
+      var result = value;
+      if (result instanceof LazyWrapper) {
+        result = result.value();
+      }
+      var index = -1,
+          length = actions.length;
+
+      while (++index < length) {
+        var action = actions[index];
+        result = action.func.apply(action.thisArg, arrayPush([result], action.args));
+      }
+      return result;
+    }
+
+    /**
+     * Performs a binary search of `array` to determine the index at which `value`
+     * should be inserted into `array` in order to maintain its sort order.
+     *
+     * @private
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {boolean} [retHighest] Specify returning the highest qualified index.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
+     */
+    function binaryIndex(array, value, retHighest) {
+      var low = 0,
+          high = array ? array.length : low;
+
+      if (typeof value == 'number' && value === value && high <= HALF_MAX_ARRAY_LENGTH) {
+        while (low < high) {
+          var mid = (low + high) >>> 1,
+              computed = array[mid];
+
+          if ((retHighest ? (computed <= value) : (computed < value)) && computed !== null) {
+            low = mid + 1;
+          } else {
+            high = mid;
+          }
+        }
+        return high;
+      }
+      return binaryIndexBy(array, value, identity, retHighest);
+    }
+
+    /**
+     * This function is like `binaryIndex` except that it invokes `iteratee` for
+     * `value` and each element of `array` to compute their sort ranking. The
+     * iteratee is invoked with one argument; (value).
+     *
+     * @private
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {Function} iteratee The function invoked per iteration.
+     * @param {boolean} [retHighest] Specify returning the highest qualified index.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
+     */
+    function binaryIndexBy(array, value, iteratee, retHighest) {
+      value = iteratee(value);
+
+      var low = 0,
+          high = array ? array.length : 0,
+          valIsNaN = value !== value,
+          valIsNull = value === null,
+          valIsUndef = value === undefined;
+
+      while (low < high) {
+        var mid = nativeFloor((low + high) / 2),
+            computed = iteratee(array[mid]),
+            isDef = computed !== undefined,
+            isReflexive = computed === computed;
+
+        if (valIsNaN) {
+          var setLow = isReflexive || retHighest;
+        } else if (valIsNull) {
+          setLow = isReflexive && isDef && (retHighest || computed != null);
+        } else if (valIsUndef) {
+          setLow = isReflexive && (retHighest || isDef);
+        } else if (computed == null) {
+          setLow = false;
+        } else {
+          setLow = retHighest ? (computed <= value) : (computed < value);
+        }
+        if (setLow) {
+          low = mid + 1;
+        } else {
+          high = mid;
+        }
+      }
+      return nativeMin(high, MAX_ARRAY_INDEX);
+    }
+
+    /**
+     * A specialized version of `baseCallback` which only supports `this` binding
+     * and specifying the number of arguments to provide to `func`.
+     *
+     * @private
+     * @param {Function} func The function to bind.
+     * @param {*} thisArg The `this` binding of `func`.
+     * @param {number} [argCount] The number of arguments to provide to `func`.
+     * @returns {Function} Returns the callback.
+     */
+    function bindCallback(func, thisArg, argCount) {
       if (typeof func != 'function') {
         return identity;
       }
-      // exit early for no `thisArg` or already bound by `Function#bind`
-      if (typeof thisArg == 'undefined' || !('prototype' in func)) {
-        return func;
-      }
-      var bindData = func.__bindData__;
-      if (typeof bindData == 'undefined') {
-        if (support.funcNames) {
-          bindData = !func.name;
-        }
-        bindData = bindData || !support.funcDecomp;
-        if (!bindData) {
-          var source = fnToString.call(func);
-          if (!support.funcNames) {
-            bindData = !reFuncName.test(source);
-          }
-          if (!bindData) {
-            // checks if `func` references the `this` keyword and stores the result
-            bindData = reThis.test(source);
-            setBindData(func, bindData);
-          }
-        }
-      }
-      // exit early if there are no `this` references or `func` is bound
-      if (bindData === false || (bindData !== true && bindData[1] & 1)) {
+      if (thisArg === undefined) {
         return func;
       }
       switch (argCount) {
         case 1: return function(value) {
           return func.call(thisArg, value);
         };
-        case 2: return function(a, b) {
-          return func.call(thisArg, a, b);
-        };
         case 3: return function(value, index, collection) {
           return func.call(thisArg, value, index, collection);
         };
         case 4: return function(accumulator, value, index, collection) {
           return func.call(thisArg, accumulator, value, index, collection);
         };
-      }
-      return bind(func, thisArg);
-    }
-
-    /**
-     * The base implementation of `createWrapper` that creates the wrapper and
-     * sets its meta data.
-     *
-     * @private
-     * @param {Array} bindData The bind data array.
-     * @returns {Function} Returns the new function.
-     */
-    function baseCreateWrapper(bindData) {
-      var func = bindData[0],
-          bitmask = bindData[1],
-          partialArgs = bindData[2],
-          partialRightArgs = bindData[3],
-          thisArg = bindData[4],
-          arity = bindData[5];
-
-      var isBind = bitmask & 1,
-          isBindKey = bitmask & 2,
-          isCurry = bitmask & 4,
-          isCurryBound = bitmask & 8,
-          key = func;
-
-      function bound() {
-        var thisBinding = isBind ? thisArg : this;
-        if (partialArgs) {
-          var args = slice(partialArgs);
-          push.apply(args, arguments);
-        }
-        if (partialRightArgs || isCurry) {
-          args || (args = slice(arguments));
-          if (partialRightArgs) {
-            push.apply(args, partialRightArgs);
-          }
-          if (isCurry && args.length < arity) {
-            bitmask |= 16 & ~32;
-            return baseCreateWrapper([func, (isCurryBound ? bitmask : bitmask & ~3), args, null, thisArg, arity]);
-          }
-        }
-        args || (args = arguments);
-        if (isBindKey) {
-          func = thisBinding[key];
-        }
-        if (this instanceof bound) {
-          thisBinding = baseCreate(func.prototype);
-          var result = func.apply(thisBinding, args);
-          return isObject(result) ? result : thisBinding;
-        }
-        return func.apply(thisBinding, args);
-      }
-      setBindData(bound, bindData);
-      return bound;
-    }
-
-    /**
-     * The base implementation of `_.difference` that accepts a single array
-     * of values to exclude.
-     *
-     * @private
-     * @param {Array} array The array to process.
-     * @param {Array} [values] The array of values to exclude.
-     * @returns {Array} Returns a new array of filtered values.
-     */
-    function baseDifference(array, values) {
-      var index = -1,
-          indexOf = getIndexOf(),
-          length = array ? array.length : 0,
-          isLarge = length >= largeArraySize && indexOf === baseIndexOf,
-          result = [];
-
-      if (isLarge) {
-        var cache = createCache(values);
-        if (cache) {
-          indexOf = cacheIndexOf;
-          values = cache;
-        } else {
-          isLarge = false;
-        }
-      }
-      while (++index < length) {
-        var value = array[index];
-        if (indexOf(values, value) < 0) {
-          result.push(value);
-        }
-      }
-      if (isLarge) {
-        releaseObject(values);
-      }
+        case 5: return function(value, other, key, object, source) {
+          return func.call(thisArg, value, other, key, object, source);
+        };
+      }
+      return function() {
+        return func.apply(thisArg, arguments);
+      };
+    }
+
+    /**
+     * Creates a clone of the given array buffer.
+     *
+     * @private
+     * @param {ArrayBuffer} buffer The array buffer to clone.
+     * @returns {ArrayBuffer} Returns the cloned array buffer.
+     */
+    function bufferClone(buffer) {
+      var result = new ArrayBuffer(buffer.byteLength),
+          view = new Uint8Array(result);
+
+      view.set(new Uint8Array(buffer));
       return result;
     }
 
     /**
-     * The base implementation of `_.flatten` without support for callback
-     * shorthands or `thisArg` binding.
-     *
-     * @private
-     * @param {Array} array The array to flatten.
-     * @param {boolean} [isShallow=false] A flag to restrict flattening to a single level.
-     * @param {boolean} [isStrict=false] A flag to restrict flattening to arrays and `arguments` objects.
-     * @param {number} [fromIndex=0] The index to start from.
-     * @returns {Array} Returns a new flattened array.
-     */
-    function baseFlatten(array, isShallow, isStrict, fromIndex) {
-      var index = (fromIndex || 0) - 1,
-          length = array ? array.length : 0,
-          result = [];
-
-      while (++index < length) {
-        var value = array[index];
-
-        if (value && typeof value == 'object' && typeof value.length == 'number'
-            && (isArray(value) || isArguments(value))) {
-          // recursively flatten arrays (susceptible to call stack limits)
-          if (!isShallow) {
-            value = baseFlatten(value, isShallow, isStrict);
-          }
-          var valIndex = -1,
-              valLength = value.length,
-              resIndex = result.length;
-
-          result.length += valLength;
-          while (++valIndex < valLength) {
-            result[resIndex++] = value[valIndex];
-          }
-        } else if (!isStrict) {
-          result.push(value);
-        }
+     * Creates an array that is the composition of partially applied arguments,
+     * placeholders, and provided arguments into a single array of arguments.
+     *
+     * @private
+     * @param {Array|Object} args The provided arguments.
+     * @param {Array} partials The arguments to prepend to those provided.
+     * @param {Array} holders The `partials` placeholder indexes.
+     * @returns {Array} Returns the new array of composed arguments.
+     */
+    function composeArgs(args, partials, holders) {
+      var holdersLength = holders.length,
+          argsIndex = -1,
+          argsLength = nativeMax(args.length - holdersLength, 0),
+          leftIndex = -1,
+          leftLength = partials.length,
+          result = Array(leftLength + argsLength);
+
+      while (++leftIndex < leftLength) {
+        result[leftIndex] = partials[leftIndex];
+      }
+      while (++argsIndex < holdersLength) {
+        result[holders[argsIndex]] = args[argsIndex];
+      }
+      while (argsLength--) {
+        result[leftIndex++] = args[argsIndex++];
       }
       return result;
     }
 
     /**
-     * The base implementation of `_.isEqual`, without support for `thisArg` binding,
-     * that allows partial "_.where" style comparisons.
-     *
-     * @private
-     * @param {*} a The value to compare.
-     * @param {*} b The other value to compare.
-     * @param {Function} [callback] The function to customize comparing values.
-     * @param {Function} [isWhere=false] A flag to indicate performing partial comparisons.
-     * @param {Array} [stackA=[]] Tracks traversed `a` objects.
-     * @param {Array} [stackB=[]] Tracks traversed `b` objects.
-     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
-     */
-    function baseIsEqual(a, b, callback, isWhere, stackA, stackB) {
-      // used to indicate that when comparing objects, `a` has at least the properties of `b`
-      if (callback) {
-        var result = callback(a, b);
-        if (typeof result != 'undefined') {
-          return !!result;
-        }
-      }
-      // exit early for identical values
-      if (a === b) {
-        // treat `+0` vs. `-0` as not equal
-        return a !== 0 || (1 / a == 1 / b);
-      }
-      var type = typeof a,
-          otherType = typeof b;
-
-      // exit early for unlike primitive values
-      if (a === a &&
-          !(a && objectTypes[type]) &&
-          !(b && objectTypes[otherType])) {
-        return false;
-      }
-      // exit early for `null` and `undefined` avoiding ES3's Function#call behavior
-      // http://es5.github.io/#x15.3.4.4
-      if (a == null || b == null) {
-        return a === b;
-      }
-      // compare [[Class]] names
-      var className = toString.call(a),
-          otherClass = toString.call(b);
-
-      if (className == argsClass) {
-        className = objectClass;
-      }
-      if (otherClass == argsClass) {
-        otherClass = objectClass;
-      }
-      if (className != otherClass) {
-        return false;
-      }
-      switch (className) {
-        case boolClass:
-        case dateClass:
-          // coerce dates and booleans to numbers, dates to milliseconds and booleans
-          // to `1` or `0` treating invalid dates coerced to `NaN` as not equal
-          return +a == +b;
-
-        case numberClass:
-          // treat `NaN` vs. `NaN` as equal
-          return (a != +a)
-            ? b != +b
-            // but treat `+0` vs. `-0` as not equal
-            : (a == 0 ? (1 / a == 1 / b) : a == +b);
-
-        case regexpClass:
-        case stringClass:
-          // coerce regexes to strings (http://es5.github.io/#x15.10.6.4)
-          // treat string primitives and their corresponding object instances as equal
-          return a == String(b);
-      }
-      var isArr = className == arrayClass;
-      if (!isArr) {
-        // unwrap any `lodash` wrapped values
-        var aWrapped = hasOwnProperty.call(a, '__wrapped__'),
-            bWrapped = hasOwnProperty.call(b, '__wrapped__');
-
-        if (aWrapped || bWrapped) {
-          return baseIsEqual(aWrapped ? a.__wrapped__ : a, bWrapped ? b.__wrapped__ : b, callback, isWhere, stackA, stackB);
-        }
-        // exit for functions and DOM nodes
-        if (className != objectClass) {
-          return false;
-        }
-        // in older versions of Opera, `arguments` objects have `Array` constructors
-        var ctorA = a.constructor,
-            ctorB = b.constructor;
-
-        // non `Object` object instances with different constructors are not equal
-        if (ctorA != ctorB &&
-              !(isFunction(ctorA) && ctorA instanceof ctorA && isFunction(ctorB) && ctorB instanceof ctorB) &&
-              ('constructor' in a && 'constructor' in b)
-            ) {
-          return false;
-        }
-      }
-      // assume cyclic structures are equal
-      // the algorithm for detecting cyclic structures is adapted from ES 5.1
-      // section 15.12.3, abstract operation `JO` (http://es5.github.io/#x15.12.3)
-      var initedStack = !stackA;
-      stackA || (stackA = getArray());
-      stackB || (stackB = getArray());
-
-      var length = stackA.length;
-      while (length--) {
-        if (stackA[length] == a) {
-          return stackB[length] == b;
-        }
-      }
-      var size = 0;
-      result = true;
-
-      // add `a` and `b` to the stack of traversed objects
-      stackA.push(a);
-      stackB.push(b);
-
-      // recursively compare objects and arrays (susceptible to call stack limits)
-      if (isArr) {
-        // compare lengths to determine if a deep comparison is necessary
-        length = a.length;
-        size = b.length;
-        result = size == length;
-
-        if (result || isWhere) {
-          // deep compare the contents, ignoring non-numeric properties
-          while (size--) {
-            var index = length,
-                value = b[size];
-
-            if (isWhere) {
-              while (index--) {
-                if ((result = baseIsEqual(a[index], value, callback, isWhere, stackA, stackB))) {
-                  break;
-                }
-              }
-            } else if (!(result = baseIsEqual(a[size], value, callback, isWhere, stackA, stackB))) {
-              break;
-            }
-          }
-        }
-      }
-      else {
-        // deep compare objects using `forIn`, instead of `forOwn`, to avoid `Object.keys`
-        // which, in this case, is more costly
-        forIn(b, function(value, key, b) {
-          if (hasOwnProperty.call(b, key)) {
-            // count the number of properties.
-            size++;
-            // deep compare each property value.
-            return (result = hasOwnProperty.call(a, key) && baseIsEqual(a[key], value, callback, isWhere, stackA, stackB));
-          }
-        });
-
-        if (result && !isWhere) {
-          // ensure both objects have the same number of properties
-          forIn(a, function(value, key, a) {
-            if (hasOwnProperty.call(a, key)) {
-              // `size` will be `-1` if `a` has more properties than `b`
-              return (result = --size > -1);
-            }
-          });
-        }
-      }
-      stackA.pop();
-      stackB.pop();
-
-      if (initedStack) {
-        releaseArray(stackA);
-        releaseArray(stackB);
+     * This function is like `composeArgs` except that the arguments composition
+     * is tailored for `_.partialRight`.
+     *
+     * @private
+     * @param {Array|Object} args The provided arguments.
+     * @param {Array} partials The arguments to append to those provided.
+     * @param {Array} holders The `partials` placeholder indexes.
+     * @returns {Array} Returns the new array of composed arguments.
+     */
+    function composeArgsRight(args, partials, holders) {
+      var holdersIndex = -1,
+          holdersLength = holders.length,
+          argsIndex = -1,
+          argsLength = nativeMax(args.length - holdersLength, 0),
+          rightIndex = -1,
+          rightLength = partials.length,
+          result = Array(argsLength + rightLength);
+
+      while (++argsIndex < argsLength) {
+        result[argsIndex] = args[argsIndex];
+      }
+      var offset = argsIndex;
+      while (++rightIndex < rightLength) {
+        result[offset + rightIndex] = partials[rightIndex];
+      }
+      while (++holdersIndex < holdersLength) {
+        result[offset + holders[holdersIndex]] = args[argsIndex++];
       }
       return result;
     }
 
     /**
-     * The base implementation of `_.merge` without argument juggling or support
-     * for `thisArg` binding.
-     *
-     * @private
-     * @param {Object} object The destination object.
-     * @param {Object} source The source object.
-     * @param {Function} [callback] The function to customize merging properties.
-     * @param {Array} [stackA=[]] Tracks traversed source objects.
-     * @param {Array} [stackB=[]] Associates values with source counterparts.
-     */
-    function baseMerge(object, source, callback, stackA, stackB) {
-      (isArray(source) ? forEach : forOwn)(source, function(source, key) {
-        var found,
-            isArr,
-            result = source,
-            value = object[key];
-
-        if (source && ((isArr = isArray(source)) || isPlainObject(source))) {
-          // avoid merging previously merged cyclic sources
-          var stackLength = stackA.length;
-          while (stackLength--) {
-            if ((found = stackA[stackLength] == source)) {
-              value = stackB[stackLength];
-              break;
-            }
-          }
-          if (!found) {
-            var isShallow;
-            if (callback) {
-              result = callback(value, source);
-              if ((isShallow = typeof result != 'undefined')) {
-                value = result;
-              }
-            }
-            if (!isShallow) {
-              value = isArr
-                ? (isArray(value) ? value : [])
-                : (isPlainObject(value) ? value : {});
-            }
-            // add `source` and associated `value` to the stack of traversed objects
-            stackA.push(source);
-            stackB.push(value);
-
-            // recursively merge objects and arrays (susceptible to call stack limits)
-            if (!isShallow) {
-              baseMerge(value, source, callback, stackA, stackB);
-            }
-          }
-        }
-        else {
-          if (callback) {
-            result = callback(value, source);
-            if (typeof result == 'undefined') {
-              result = source;
-            }
-          }
-          if (typeof result != 'undefined') {
-            value = result;
-          }
-        }
-        object[key] = value;
-      });
-    }
-
-    /**
-     * The base implementation of `_.random` without argument juggling or support
-     * for returning floating-point numbers.
-     *
-     * @private
-     * @param {number} min The minimum possible value.
-     * @param {number} max The maximum possible value.
-     * @returns {number} Returns a random number.
-     */
-    function baseRandom(min, max) {
-      return min + floor(nativeRandom() * (max - min + 1));
-    }
-
-    /**
-     * The base implementation of `_.uniq` without support for callback shorthands
-     * or `thisArg` binding.
-     *
-     * @private
-     * @param {Array} array The array to process.
-     * @param {boolean} [isSorted=false] A flag to indicate that `array` is sorted.
-     * @param {Function} [callback] The function called per iteration.
-     * @returns {Array} Returns a duplicate-value-free array.
-     */
-    function baseUniq(array, isSorted, callback) {
-      var index = -1,
-          indexOf = getIndexOf(),
-          length = array ? array.length : 0,
-          result = [];
-
-      var isLarge = !isSorted && length >= largeArraySize && indexOf === baseIndexOf,
-          seen = (callback || isLarge) ? getArray() : result;
-
-      if (isLarge) {
-        var cache = createCache(seen);
-        indexOf = cacheIndexOf;
-        seen = cache;
-      }
-      while (++index < length) {
-        var value = array[index],
-            computed = callback ? callback(value, index, array) : value;
-
-        if (isSorted
-              ? !index || seen[seen.length - 1] !== computed
-              : indexOf(seen, computed) < 0
-            ) {
-          if (callback || isLarge) {
-            seen.push(computed);
-          }
-          result.push(value);
-        }
-      }
-      if (isLarge) {
-        releaseArray(seen.array);
-        releaseObject(seen);
-      } else if (callback) {
-        releaseArray(seen);
-      }
-      return result;
-    }
-
-    /**
-     * Creates a function that aggregates a collection, creating an object composed
-     * of keys generated from the results of running each element of the collection
-     * through a callback. The given `setter` function sets the keys and values
-     * of the composed object.
-     *
-     * @private
-     * @param {Function} setter The setter function.
+     * Creates a `_.countBy`, `_.groupBy`, `_.indexBy`, or `_.partition` function.
+     *
+     * @private
+     * @param {Function} setter The function to set keys and values of the accumulator object.
+     * @param {Function} [initializer] The function to initialize the accumulator object.
      * @returns {Function} Returns the new aggregator function.
      */
-    function createAggregator(setter) {
-      return function(collection, callback, thisArg) {
-        var result = {};
-        callback = lodash.createCallback(callback, thisArg, 3);
-
-        var index = -1,
-            length = collection ? collection.length : 0;
-
-        if (typeof length == 'number') {
+    function createAggregator(setter, initializer) {
+      return function(collection, iteratee, thisArg) {
+        var result = initializer ? initializer() : {};
+        iteratee = getCallback(iteratee, thisArg, 3);
+
+        if (isArray(collection)) {
+          var index = -1,
+              length = collection.length;
+
           while (++index < length) {
             var value = collection[index];
-            setter(result, value, callback(value, index, collection), collection);
+            setter(result, value, iteratee(value, index, collection), collection);
           }
         } else {
-          forOwn(collection, function(value, key, collection) {
-            setter(result, value, callback(value, key, collection), collection);
+          baseEach(collection, function(value, key, collection) {
+            setter(result, value, iteratee(value, key, collection), collection);
           });
         }
         return result;
@@ -1370,2054 +2993,3621 @@
     }
 
     /**
-     * Creates a function that, when called, either curries or invokes `func`
-     * with an optional `this` binding and partially applied arguments.
+     * Creates a `_.assign`, `_.defaults`, or `_.merge` function.
+     *
+     * @private
+     * @param {Function} assigner The function to assign values.
+     * @returns {Function} Returns the new assigner function.
+     */
+    function createAssigner(assigner) {
+      return restParam(function(object, sources) {
+        var index = -1,
+            length = object == null ? 0 : sources.length,
+            customizer = length > 2 ? sources[length - 2] : undefined,
+            guard = length > 2 ? sources[2] : undefined,
+            thisArg = length > 1 ? sources[length - 1] : undefined;
+
+        if (typeof customizer == 'function') {
+          customizer = bindCallback(customizer, thisArg, 5);
+          length -= 2;
+        } else {
+          customizer = typeof thisArg == 'function' ? thisArg : undefined;
+          length -= (customizer ? 1 : 0);
+        }
+        if (guard && isIterateeCall(sources[0], sources[1], guard)) {
+          customizer = length < 3 ? undefined : customizer;
+          length = 1;
+        }
+        while (++index < length) {
+          var source = sources[index];
+          if (source) {
+            assigner(object, source, customizer);
+          }
+        }
+        return object;
+      });
+    }
+
+    /**
+     * Creates a `baseEach` or `baseEachRight` function.
+     *
+     * @private
+     * @param {Function} eachFunc The function to iterate over a collection.
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new base function.
+     */
+    function createBaseEach(eachFunc, fromRight) {
+      return function(collection, iteratee) {
+        var length = collection ? getLength(collection) : 0;
+        if (!isLength(length)) {
+          return eachFunc(collection, iteratee);
+        }
+        var index = fromRight ? length : -1,
+            iterable = toObject(collection);
+
+        while ((fromRight ? index-- : ++index < length)) {
+          if (iteratee(iterable[index], index, iterable) === false) {
+            break;
+          }
+        }
+        return collection;
+      };
+    }
+
+    /**
+     * Creates a base function for `_.forIn` or `_.forInRight`.
+     *
+     * @private
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new base function.
+     */
+    function createBaseFor(fromRight) {
+      return function(object, iteratee, keysFunc) {
+        var iterable = toObject(object),
+            props = keysFunc(object),
+            length = props.length,
+            index = fromRight ? length : -1;
+
+        while ((fromRight ? index-- : ++index < length)) {
+          var key = props[index];
+          if (iteratee(iterable[key], key, iterable) === false) {
+            break;
+          }
+        }
+        return object;
+      };
+    }
+
+    /**
+     * Creates a function that wraps `func` and invokes it with the `this`
+     * binding of `thisArg`.
+     *
+     * @private
+     * @param {Function} func The function to bind.
+     * @param {*} [thisArg] The `this` binding of `func`.
+     * @returns {Function} Returns the new bound function.
+     */
+    function createBindWrapper(func, thisArg) {
+      var Ctor = createCtorWrapper(func);
+
+      function wrapper() {
+        var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
+        return fn.apply(thisArg, arguments);
+      }
+      return wrapper;
+    }
+
+    /**
+     * Creates a `Set` cache object to optimize linear searches of large arrays.
+     *
+     * @private
+     * @param {Array} [values] The values to cache.
+     * @returns {null|Object} Returns the new cache object if `Set` is supported, else `null`.
+     */
+    function createCache(values) {
+      return (nativeCreate && Set) ? new SetCache(values) : null;
+    }
+
+    /**
+     * Creates a function that produces compound words out of the words in a
+     * given string.
+     *
+     * @private
+     * @param {Function} callback The function to combine each word.
+     * @returns {Function} Returns the new compounder function.
+     */
+    function createCompounder(callback) {
+      return function(string) {
+        var index = -1,
+            array = words(deburr(string)),
+            length = array.length,
+            result = '';
+
+        while (++index < length) {
+          result = callback(result, array[index], index);
+        }
+        return result;
+      };
+    }
+
+    /**
+     * Creates a function that produces an instance of `Ctor` regardless of
+     * whether it was invoked as part of a `new` expression or by `call` or `apply`.
+     *
+     * @private
+     * @param {Function} Ctor The constructor to wrap.
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createCtorWrapper(Ctor) {
+      return function() {
+        // Use a `switch` statement to work with class constructors.
+        // See http://ecma-international.org/ecma-262/6.0/#sec-ecmascript-function-objects-call-thisargument-argumentslist
+        // for more details.
+        var args = arguments;
+        switch (args.length) {
+          case 0: return new Ctor;
+          case 1: return new Ctor(args[0]);
+          case 2: return new Ctor(args[0], args[1]);
+          case 3: return new Ctor(args[0], args[1], args[2]);
+          case 4: return new Ctor(args[0], args[1], args[2], args[3]);
+          case 5: return new Ctor(args[0], args[1], args[2], args[3], args[4]);
+          case 6: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5]);
+          case 7: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5], args[6]);
+        }
+        var thisBinding = baseCreate(Ctor.prototype),
+            result = Ctor.apply(thisBinding, args);
+
+        // Mimic the constructor's `return` behavior.
+        // See https://es5.github.io/#x13.2.2 for more details.
+        return isObject(result) ? result : thisBinding;
+      };
+    }
+
+    /**
+     * Creates a `_.curry` or `_.curryRight` function.
+     *
+     * @private
+     * @param {boolean} flag The curry bit flag.
+     * @returns {Function} Returns the new curry function.
+     */
+    function createCurry(flag) {
+      function curryFunc(func, arity, guard) {
+        if (guard && isIterateeCall(func, arity, guard)) {
+          arity = undefined;
+        }
+        var result = createWrapper(func, flag, undefined, undefined, undefined, undefined, undefined, arity);
+        result.placeholder = curryFunc.placeholder;
+        return result;
+      }
+      return curryFunc;
+    }
+
+    /**
+     * Creates a `_.defaults` or `_.defaultsDeep` function.
+     *
+     * @private
+     * @param {Function} assigner The function to assign values.
+     * @param {Function} customizer The function to customize assigned values.
+     * @returns {Function} Returns the new defaults function.
+     */
+    function createDefaults(assigner, customizer) {
+      return restParam(function(args) {
+        var object = args[0];
+        if (object == null) {
+          return object;
+        }
+        args.push(customizer);
+        return assigner.apply(undefined, args);
+      });
+    }
+
+    /**
+     * Creates a `_.max` or `_.min` function.
+     *
+     * @private
+     * @param {Function} comparator The function used to compare values.
+     * @param {*} exValue The initial extremum value.
+     * @returns {Function} Returns the new extremum function.
+     */
+    function createExtremum(comparator, exValue) {
+      return function(collection, iteratee, thisArg) {
+        if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
+          iteratee = undefined;
+        }
+        iteratee = getCallback(iteratee, thisArg, 3);
+        if (iteratee.length == 1) {
+          collection = isArray(collection) ? collection : toIterable(collection);
+          var result = arrayExtremum(collection, iteratee, comparator, exValue);
+          if (!(collection.length && result === exValue)) {
+            return result;
+          }
+        }
+        return baseExtremum(collection, iteratee, comparator, exValue);
+      };
+    }
+
+    /**
+     * Creates a `_.find` or `_.findLast` function.
+     *
+     * @private
+     * @param {Function} eachFunc The function to iterate over a collection.
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new find function.
+     */
+    function createFind(eachFunc, fromRight) {
+      return function(collection, predicate, thisArg) {
+        predicate = getCallback(predicate, thisArg, 3);
+        if (isArray(collection)) {
+          var index = baseFindIndex(collection, predicate, fromRight);
+          return index > -1 ? collection[index] : undefined;
+        }
+        return baseFind(collection, predicate, eachFunc);
+      };
+    }
+
+    /**
+     * Creates a `_.findIndex` or `_.findLastIndex` function.
+     *
+     * @private
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new find function.
+     */
+    function createFindIndex(fromRight) {
+      return function(array, predicate, thisArg) {
+        if (!(array && array.length)) {
+          return -1;
+        }
+        predicate = getCallback(predicate, thisArg, 3);
+        return baseFindIndex(array, predicate, fromRight);
+      };
+    }
+
+    /**
+     * Creates a `_.findKey` or `_.findLastKey` function.
+     *
+     * @private
+     * @param {Function} objectFunc The function to iterate over an object.
+     * @returns {Function} Returns the new find function.
+     */
+    function createFindKey(objectFunc) {
+      return function(object, predicate, thisArg) {
+        predicate = getCallback(predicate, thisArg, 3);
+        return baseFind(object, predicate, objectFunc, true);
+      };
+    }
+
+    /**
+     * Creates a `_.flow` or `_.flowRight` function.
+     *
+     * @private
+     * @param {boolean} [fromRight] Specify iterating from right to left.
+     * @returns {Function} Returns the new flow function.
+     */
+    function createFlow(fromRight) {
+      return function() {
+        var wrapper,
+            length = arguments.length,
+            index = fromRight ? length : -1,
+            leftIndex = 0,
+            funcs = Array(length);
+
+        while ((fromRight ? index-- : ++index < length)) {
+          var func = funcs[leftIndex++] = arguments[index];
+          if (typeof func != 'function') {
+            throw new TypeError(FUNC_ERROR_TEXT);
+          }
+          if (!wrapper && LodashWrapper.prototype.thru && getFuncName(func) == 'wrapper') {
+            wrapper = new LodashWrapper([], true);
+          }
+        }
+        index = wrapper ? -1 : length;
+        while (++index < length) {
+          func = funcs[index];
+
+          var funcName = getFuncName(func),
+              data = funcName == 'wrapper' ? getData(func) : undefined;
+
+          if (data && isLaziable(data[0]) && data[1] == (ARY_FLAG | CURRY_FLAG | PARTIAL_FLAG | REARG_FLAG) && !data[4].length && data[9] == 1) {
+            wrapper = wrapper[getFuncName(data[0])].apply(wrapper, data[3]);
+          } else {
+            wrapper = (func.length == 1 && isLaziable(func)) ? wrapper[funcName]() : wrapper.thru(func);
+          }
+        }
+        return function() {
+          var args = arguments,
+              value = args[0];
+
+          if (wrapper && args.length == 1 && isArray(value) && value.length >= LARGE_ARRAY_SIZE) {
+            return wrapper.plant(value).value();
+          }
+          var index = 0,
+              result = length ? funcs[index].apply(this, args) : value;
+
+          while (++index < length) {
+            result = funcs[index].call(this, result);
+          }
+          return result;
+        };
+      };
+    }
+
+    /**
+     * Creates a function for `_.forEach` or `_.forEachRight`.
+     *
+     * @private
+     * @param {Function} arrayFunc The function to iterate over an array.
+     * @param {Function} eachFunc The function to iterate over a collection.
+     * @returns {Function} Returns the new each function.
+     */
+    function createForEach(arrayFunc, eachFunc) {
+      return function(collection, iteratee, thisArg) {
+        return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
+          ? arrayFunc(collection, iteratee)
+          : eachFunc(collection, bindCallback(iteratee, thisArg, 3));
+      };
+    }
+
+    /**
+     * Creates a function for `_.forIn` or `_.forInRight`.
+     *
+     * @private
+     * @param {Function} objectFunc The function to iterate over an object.
+     * @returns {Function} Returns the new each function.
+     */
+    function createForIn(objectFunc) {
+      return function(object, iteratee, thisArg) {
+        if (typeof iteratee != 'function' || thisArg !== undefined) {
+          iteratee = bindCallback(iteratee, thisArg, 3);
+        }
+        return objectFunc(object, iteratee, keysIn);
+      };
+    }
+
+    /**
+     * Creates a function for `_.forOwn` or `_.forOwnRight`.
+     *
+     * @private
+     * @param {Function} objectFunc The function to iterate over an object.
+     * @returns {Function} Returns the new each function.
+     */
+    function createForOwn(objectFunc) {
+      return function(object, iteratee, thisArg) {
+        if (typeof iteratee != 'function' || thisArg !== undefined) {
+          iteratee = bindCallback(iteratee, thisArg, 3);
+        }
+        return objectFunc(object, iteratee);
+      };
+    }
+
+    /**
+     * Creates a function for `_.mapKeys` or `_.mapValues`.
+     *
+     * @private
+     * @param {boolean} [isMapKeys] Specify mapping keys instead of values.
+     * @returns {Function} Returns the new map function.
+     */
+    function createObjectMapper(isMapKeys) {
+      return function(object, iteratee, thisArg) {
+        var result = {};
+        iteratee = getCallback(iteratee, thisArg, 3);
+
+        baseForOwn(object, function(value, key, object) {
+          var mapped = iteratee(value, key, object);
+          key = isMapKeys ? mapped : key;
+          value = isMapKeys ? value : mapped;
+          result[key] = value;
+        });
+        return result;
+      };
+    }
+
+    /**
+     * Creates a function for `_.padLeft` or `_.padRight`.
+     *
+     * @private
+     * @param {boolean} [fromRight] Specify padding from the right.
+     * @returns {Function} Returns the new pad function.
+     */
+    function createPadDir(fromRight) {
+      return function(string, length, chars) {
+        string = baseToString(string);
+        return (fromRight ? string : '') + createPadding(string, length, chars) + (fromRight ? '' : string);
+      };
+    }
+
+    /**
+     * Creates a `_.partial` or `_.partialRight` function.
+     *
+     * @private
+     * @param {boolean} flag The partial bit flag.
+     * @returns {Function} Returns the new partial function.
+     */
+    function createPartial(flag) {
+      var partialFunc = restParam(function(func, partials) {
+        var holders = replaceHolders(partials, partialFunc.placeholder);
+        return createWrapper(func, flag, undefined, partials, holders);
+      });
+      return partialFunc;
+    }
+
+    /**
+     * Creates a function for `_.reduce` or `_.reduceRight`.
+     *
+     * @private
+     * @param {Function} arrayFunc The function to iterate over an array.
+     * @param {Function} eachFunc The function to iterate over a collection.
+     * @returns {Function} Returns the new each function.
+     */
+    function createReduce(arrayFunc, eachFunc) {
+      return function(collection, iteratee, accumulator, thisArg) {
+        var initFromArray = arguments.length < 3;
+        return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
+          ? arrayFunc(collection, iteratee, accumulator, initFromArray)
+          : baseReduce(collection, getCallback(iteratee, thisArg, 4), accumulator, initFromArray, eachFunc);
+      };
+    }
+
+    /**
+     * Creates a function that wraps `func` and invokes it with optional `this`
+     * binding of, partial application, and currying.
      *
      * @private
      * @param {Function|string} func The function or method name to reference.
-     * @param {number} bitmask The bitmask of method flags to compose.
+     * @param {number} bitmask The bitmask of flags. See `createWrapper` for more details.
+     * @param {*} [thisArg] The `this` binding of `func`.
+     * @param {Array} [partials] The arguments to prepend to those provided to the new function.
+     * @param {Array} [holders] The `partials` placeholder indexes.
+     * @param {Array} [partialsRight] The arguments to append to those provided to the new function.
+     * @param {Array} [holdersRight] The `partialsRight` placeholder indexes.
+     * @param {Array} [argPos] The argument positions of the new function.
+     * @param {number} [ary] The arity cap of `func`.
+     * @param {number} [arity] The arity of `func`.
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createHybridWrapper(func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity) {
+      var isAry = bitmask & ARY_FLAG,
+          isBind = bitmask & BIND_FLAG,
+          isBindKey = bitmask & BIND_KEY_FLAG,
+          isCurry = bitmask & CURRY_FLAG,
+          isCurryBound = bitmask & CURRY_BOUND_FLAG,
+          isCurryRight = bitmask & CURRY_RIGHT_FLAG,
+          Ctor = isBindKey ? undefined : createCtorWrapper(func);
+
+      function wrapper() {
+        // Avoid `arguments` object use disqualifying optimizations by
+        // converting it to an array before providing it to other functions.
+        var length = arguments.length,
+            index = length,
+            args = Array(length);
+
+        while (index--) {
+          args[index] = arguments[index];
+        }
+        if (partials) {
+          args = composeArgs(args, partials, holders);
+        }
+        if (partialsRight) {
+          args = composeArgsRight(args, partialsRight, holdersRight);
+        }
+        if (isCurry || isCurryRight) {
+          var placeholder = wrapper.placeholder,
+              argsHolders = replaceHolders(args, placeholder);
+
+          length -= argsHolders.length;
+          if (length < arity) {
+            var newArgPos = argPos ? arrayCopy(argPos) : undefined,
+                newArity = nativeMax(arity - length, 0),
+                newsHolders = isCurry ? argsHolders : undefined,
+                newHoldersRight = isCurry ? undefined : argsHolders,
+                newPartials = isCurry ? args : undefined,
+                newPartialsRight = isCurry ? undefined : args;
+
+            bitmask |= (isCurry ? PARTIAL_FLAG : PARTIAL_RIGHT_FLAG);
+            bitmask &= ~(isCurry ? PARTIAL_RIGHT_FLAG : PARTIAL_FLAG);
+
+            if (!isCurryBound) {
+              bitmask &= ~(BIND_FLAG | BIND_KEY_FLAG);
+            }
+            var newData = [func, bitmask, thisArg, newPartials, newsHolders, newPartialsRight, newHoldersRight, newArgPos, ary, newArity],
+                result = createHybridWrapper.apply(undefined, newData);
+
+            if (isLaziable(func)) {
+              setData(result, newData);
+            }
+            result.placeholder = placeholder;
+            return result;
+          }
+        }
+        var thisBinding = isBind ? thisArg : this,
+            fn = isBindKey ? thisBinding[func] : func;
+
+        if (argPos) {
+          args = reorder(args, argPos);
+        }
+        if (isAry && ary < args.length) {
+          args.length = ary;
+        }
+        if (this && this !== root && this instanceof wrapper) {
+          fn = Ctor || createCtorWrapper(func);
+        }
+        return fn.apply(thisBinding, args);
+      }
+      return wrapper;
+    }
+
+    /**
+     * Creates the padding required for `string` based on the given `length`.
+     * The `chars` string is truncated if the number of characters exceeds `length`.
+     *
+     * @private
+     * @param {string} string The string to create padding for.
+     * @param {number} [length=0] The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the pad for `string`.
+     */
+    function createPadding(string, length, chars) {
+      var strLength = string.length;
+      length = +length;
+
+      if (strLength >= length || !nativeIsFinite(length)) {
+        return '';
+      }
+      var padLength = length - strLength;
+      chars = chars == null ? ' ' : (chars + '');
+      return repeat(chars, nativeCeil(padLength / chars.length)).slice(0, padLength);
+    }
+
+    /**
+     * Creates a function that wraps `func` and invokes it with the optional `this`
+     * binding of `thisArg` and the `partials` prepended to those provided to
+     * the wrapper.
+     *
+     * @private
+     * @param {Function} func The function to partially apply arguments to.
+     * @param {number} bitmask The bitmask of flags. See `createWrapper` for more details.
+     * @param {*} thisArg The `this` binding of `func`.
+     * @param {Array} partials The arguments to prepend to those provided to the new function.
+     * @returns {Function} Returns the new bound function.
+     */
+    function createPartialWrapper(func, bitmask, thisArg, partials) {
+      var isBind = bitmask & BIND_FLAG,
+          Ctor = createCtorWrapper(func);
+
+      function wrapper() {
+        // Avoid `arguments` object use disqualifying optimizations by
+        // converting it to an array before providing it `func`.
+        var argsIndex = -1,
+            argsLength = arguments.length,
+            leftIndex = -1,
+            leftLength = partials.length,
+            args = Array(leftLength + argsLength);
+
+        while (++leftIndex < leftLength) {
+          args[leftIndex] = partials[leftIndex];
+        }
+        while (argsLength--) {
+          args[leftIndex++] = arguments[++argsIndex];
+        }
+        var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
+        return fn.apply(isBind ? thisArg : this, args);
+      }
+      return wrapper;
+    }
+
+    /**
+     * Creates a `_.ceil`, `_.floor`, or `_.round` function.
+     *
+     * @private
+     * @param {string} methodName The name of the `Math` method to use when rounding.
+     * @returns {Function} Returns the new round function.
+     */
+    function createRound(methodName) {
+      var func = Math[methodName];
+      return function(number, precision) {
+        precision = precision === undefined ? 0 : (+precision || 0);
+        if (precision) {
+          precision = pow(10, precision);
+          return func(number * precision) / precision;
+        }
+        return func(number);
+      };
+    }
+
+    /**
+     * Creates a `_.sortedIndex` or `_.sortedLastIndex` function.
+     *
+     * @private
+     * @param {boolean} [retHighest] Specify returning the highest qualified index.
+     * @returns {Function} Returns the new index function.
+     */
+    function createSortedIndex(retHighest) {
+      return function(array, value, iteratee, thisArg) {
+        var callback = getCallback(iteratee);
+        return (iteratee == null && callback === baseCallback)
+          ? binaryIndex(array, value, retHighest)
+          : binaryIndexBy(array, value, callback(iteratee, thisArg, 1), retHighest);
+      };
+    }
+
+    /**
+     * Creates a function that either curries or invokes `func` with optional
+     * `this` binding and partially applied arguments.
+     *
+     * @private
+     * @param {Function|string} func The function or method name to reference.
+     * @param {number} bitmask The bitmask of flags.
      *  The bitmask may be composed of the following flags:
-     *  1 - `_.bind`
-     *  2 - `_.bindKey`
-     *  4 - `_.curry`
-     *  8 - `_.curry` (bound)
-     *  16 - `_.partial`
-     *  32 - `_.partialRight`
-     * @param {Array} [partialArgs] An array of arguments to prepend to those
-     *  provided to the new function.
-     * @param {Array} [partialRightArgs] An array of arguments to append to those
-     *  provided to the new function.
+     *     1 - `_.bind`
+     *     2 - `_.bindKey`
+     *     4 - `_.curry` or `_.curryRight` of a bound function
+     *     8 - `_.curry`
+     *    16 - `_.curryRight`
+     *    32 - `_.partial`
+     *    64 - `_.partialRight`
+     *   128 - `_.rearg`
+     *   256 - `_.ary`
      * @param {*} [thisArg] The `this` binding of `func`.
+     * @param {Array} [partials] The arguments to be partially applied.
+     * @param {Array} [holders] The `partials` placeholder indexes.
+     * @param {Array} [argPos] The argument positions of the new function.
+     * @param {number} [ary] The arity cap of `func`.
      * @param {number} [arity] The arity of `func`.
-     * @returns {Function} Returns the new function.
-     */
-    function createWrapper(func, bitmask, partialArgs, partialRightArgs, thisArg, arity) {
-      var isBind = bitmask & 1,
-          isBindKey = bitmask & 2,
-          isCurry = bitmask & 4,
-          isCurryBound = bitmask & 8,
-          isPartial = bitmask & 16,
-          isPartialRight = bitmask & 32;
-
-      if (!isBindKey && !isFunction(func)) {
-        throw new TypeError;
-      }
-      if (isPartial && !partialArgs.length) {
-        bitmask &= ~16;
-        isPartial = partialArgs = false;
-      }
-      if (isPartialRight && !partialRightArgs.length) {
-        bitmask &= ~32;
-        isPartialRight = partialRightArgs = false;
-      }
-      var bindData = func && func.__bindData__;
-      if (bindData && bindData !== true) {
-        // clone `bindData`
-        bindData = slice(bindData);
-        if (bindData[2]) {
-          bindData[2] = slice(bindData[2]);
-        }
-        if (bindData[3]) {
-          bindData[3] = slice(bindData[3]);
-        }
-        // set `thisBinding` is not previously bound
-        if (isBind && !(bindData[1] & 1)) {
-          bindData[4] = thisArg;
-        }
-        // set if previously bound but not currently (subsequent curried functions)
-        if (!isBind && bindData[1] & 1) {
-          bitmask |= 8;
-        }
-        // set curried arity if not yet set
-        if (isCurry && !(bindData[1] & 4)) {
-          bindData[5] = arity;
-        }
-        // append partial left arguments
-        if (isPartial) {
-          push.apply(bindData[2] || (bindData[2] = []), partialArgs);
-        }
-        // append partial right arguments
-        if (isPartialRight) {
-          unshift.apply(bindData[3] || (bindData[3] = []), partialRightArgs);
-        }
-        // merge flags
-        bindData[1] |= bitmask;
-        return createWrapper.apply(null, bindData);
-      }
-      // fast path for `_.bind`
-      var creater = (bitmask == 1 || bitmask === 17) ? baseBind : baseCreateWrapper;
-      return creater([func, bitmask, partialArgs, partialRightArgs, thisArg, arity]);
-    }
-
-    /**
-     * Used by `escape` to convert characters to HTML entities.
-     *
-     * @private
-     * @param {string} match The matched character to escape.
-     * @returns {string} Returns the escaped character.
-     */
-    function escapeHtmlChar(match) {
-      return htmlEscapes[match];
+     * @returns {Function} Returns the new wrapped function.
+     */
+    function createWrapper(func, bitmask, thisArg, partials, holders, argPos, ary, arity) {
+      var isBindKey = bitmask & BIND_KEY_FLAG;
+      if (!isBindKey && typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      var length = partials ? partials.length : 0;
+      if (!length) {
+        bitmask &= ~(PARTIAL_FLAG | PARTIAL_RIGHT_FLAG);
+        partials = holders = undefined;
+      }
+      length -= (holders ? holders.length : 0);
+      if (bitmask & PARTIAL_RIGHT_FLAG) {
+        var partialsRight = partials,
+            holdersRight = holders;
+
+        partials = holders = undefined;
+      }
+      var data = isBindKey ? undefined : getData(func),
+          newData = [func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity];
+
+      if (data) {
+        mergeData(newData, data);
+        bitmask = newData[1];
+        arity = newData[9];
+      }
+      newData[9] = arity == null
+        ? (isBindKey ? 0 : func.length)
+        : (nativeMax(arity - length, 0) || 0);
+
+      if (bitmask == BIND_FLAG) {
+        var result = createBindWrapper(newData[0], newData[2]);
+      } else if ((bitmask == PARTIAL_FLAG || bitmask == (BIND_FLAG | PARTIAL_FLAG)) && !newData[4].length) {
+        result = createPartialWrapper.apply(undefined, newData);
+      } else {
+        result = createHybridWrapper.apply(undefined, newData);
+      }
+      var setter = data ? baseSetData : setData;
+      return setter(result, newData);
+    }
+
+    /**
+     * A specialized version of `baseIsEqualDeep` for arrays with support for
+     * partial deep comparisons.
+     *
+     * @private
+     * @param {Array} array The array to compare.
+     * @param {Array} other The other array to compare.
+     * @param {Function} equalFunc The function to determine equivalents of values.
+     * @param {Function} [customizer] The function to customize comparing arrays.
+     * @param {boolean} [isLoose] Specify performing partial comparisons.
+     * @param {Array} [stackA] Tracks traversed `value` objects.
+     * @param {Array} [stackB] Tracks traversed `other` objects.
+     * @returns {boolean} Returns `true` if the arrays are equivalent, else `false`.
+     */
+    function equalArrays(array, other, equalFunc, customizer, isLoose, stackA, stackB) {
+      var index = -1,
+          arrLength = array.length,
+          othLength = other.length;
+
+      if (arrLength != othLength && !(isLoose && othLength > arrLength)) {
+        return false;
+      }
+      // Ignore non-index properties.
+      while (++index < arrLength) {
+        var arrValue = array[index],
+            othValue = other[index],
+            result = customizer ? customizer(isLoose ? othValue : arrValue, isLoose ? arrValue : othValue, index) : undefined;
+
+        if (result !== undefined) {
+          if (result) {
+            continue;
+          }
+          return false;
+        }
+        // Recursively compare arrays (susceptible to call stack limits).
+        if (isLoose) {
+          if (!arraySome(other, function(othValue) {
+                return arrValue === othValue || equalFunc(arrValue, othValue, customizer, isLoose, stackA, stackB);
+              })) {
+            return false;
+          }
+        } else if (!(arrValue === othValue || equalFunc(arrValue, othValue, customizer, isLoose, stackA, stackB))) {
+          return false;
+        }
+      }
+      return true;
+    }
+
+    /**
+     * A specialized version of `baseIsEqualDeep` for comparing objects of
+     * the same `toStringTag`.
+     *
+     * **Note:** This function only supports comparing values with tags of
+     * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
+     *
+     * @private
+     * @param {Object} object The object to compare.
+     * @param {Object} other The other object to compare.
+     * @param {string} tag The `toStringTag` of the objects to compare.
+     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
+     */
+    function equalByTag(object, other, tag) {
+      switch (tag) {
+        case boolTag:
+        case dateTag:
+          // Coerce dates and booleans to numbers, dates to milliseconds and booleans
+          // to `1` or `0` treating invalid dates coerced to `NaN` as not equal.
+          return +object == +other;
+
+        case errorTag:
+          return object.name == other.name && object.message == other.message;
+
+        case numberTag:
+          // Treat `NaN` vs. `NaN` as equal.
+          return (object != +object)
+            ? other != +other
+            : object == +other;
+
+        case regexpTag:
+        case stringTag:
+          // Coerce regexes to strings and treat strings primitives and string
+          // objects as equal. See https://es5.github.io/#x15.10.6.4 for more details.
+          return object == (other + '');
+      }
+      return false;
+    }
+
+    /**
+     * A specialized version of `baseIsEqualDeep` for objects with support for
+     * partial deep comparisons.
+     *
+     * @private
+     * @param {Object} object The object to compare.
+     * @param {Object} other The other object to compare.
+     * @param {Function} equalFunc The function to determine equivalents of values.
+     * @param {Function} [customizer] The function to customize comparing values.
+     * @param {boolean} [isLoose] Specify performing partial comparisons.
+     * @param {Array} [stackA] Tracks traversed `value` objects.
+     * @param {Array} [stackB] Tracks traversed `other` objects.
+     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
+     */
+    function equalObjects(object, other, equalFunc, customizer, isLoose, stackA, stackB) {
+      var objProps = keys(object),
+          objLength = objProps.length,
+          othProps = keys(other),
+          othLength = othProps.length;
+
+      if (objLength != othLength && !isLoose) {
+        return false;
+      }
+      var index = objLength;
+      while (index--) {
+        var key = objProps[index];
+        if (!(isLoose ? key in other : hasOwnProperty.call(other, key))) {
+          return false;
+        }
+      }
+      var skipCtor = isLoose;
+      while (++index < objLength) {
+        key = objProps[index];
+        var objValue = object[key],
+            othValue = other[key],
+            result = customizer ? customizer(isLoose ? othValue : objValue, isLoose? objValue : othValue, key) : undefined;
+
+        // Recursively compare objects (susceptible to call stack limits).
+        if (!(result === undefined ? equalFunc(objValue, othValue, customizer, isLoose, stackA, stackB) : result)) {
+          return false;
+        }
+        skipCtor || (skipCtor = key == 'constructor');
+      }
+      if (!skipCtor) {
+        var objCtor = object.constructor,
+            othCtor = other.constructor;
+
+        // Non `Object` object instances with different constructors are not equal.
+        if (objCtor != othCtor &&
+            ('constructor' in object && 'constructor' in other) &&
+            !(typeof objCtor == 'function' && objCtor instanceof objCtor &&
+              typeof othCtor == 'function' && othCtor instanceof othCtor)) {
+          return false;
+        }
+      }
+      return true;
+    }
+
+    /**
+     * Gets the appropriate "callback" function. If the `_.callback` method is
+     * customized this function returns the custom method, otherwise it returns
+     * the `baseCallback` function. If arguments are provided the chosen function
+     * is invoked with them and its result is returned.
+     *
+     * @private
+     * @returns {Function} Returns the chosen function or its result.
+     */
+    function getCallback(func, thisArg, argCount) {
+      var result = lodash.callback || callback;
+      result = result === callback ? baseCallback : result;
+      return argCount ? result(func, thisArg, argCount) : result;
+    }
+
+    /**
+     * Gets metadata for `func`.
+     *
+     * @private
+     * @param {Function} func The function to query.
+     * @returns {*} Returns the metadata for `func`.
+     */
+    var getData = !metaMap ? noop : function(func) {
+      return metaMap.get(func);
+    };
+
+    /**
+     * Gets the name of `func`.
+     *
+     * @private
+     * @param {Function} func The function to query.
+     * @returns {string} Returns the function name.
+     */
+    function getFuncName(func) {
+      var result = (func.name + ''),
+          array = realNames[result],
+          length = array ? array.length : 0;
+
+      while (length--) {
+        var data = array[length],
+            otherFunc = data.func;
+        if (otherFunc == null || otherFunc == func) {
+          return data.name;
+        }
+      }
+      return result;
     }
 
     /**
      * Gets the appropriate "indexOf" function. If the `_.indexOf` method is
-     * customized, this method returns the custom method, otherwise it returns
-     * the `baseIndexOf` function.
-     *
-     * @private
-     * @returns {Function} Returns the "indexOf" function.
-     */
-    function getIndexOf() {
-      var result = (result = lodash.indexOf) === indexOf ? baseIndexOf : result;
+     * customized this function returns the custom method, otherwise it returns
+     * the `baseIndexOf` function. If arguments are provided the chosen function
+     * is invoked with them and its result is returned.
+     *
+     * @private
+     * @returns {Function|number} Returns the chosen function or its result.
+     */
+    function getIndexOf(collection, target, fromIndex) {
+      var result = lodash.indexOf || indexOf;
+      result = result === indexOf ? baseIndexOf : result;
+      return collection ? result(collection, target, fromIndex) : result;
+    }
+
+    /**
+     * Gets the "length" property value of `object`.
+     *
+     * **Note:** This function is used to avoid a [JIT bug](https://bugs.webkit.org/show_bug.cgi?id=142792)
+     * that affects Safari on at least iOS 8.1-8.3 ARM64.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {*} Returns the "length" value.
+     */
+    var getLength = baseProperty('length');
+
+    /**
+     * Gets the propery names, values, and compare flags of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the match data of `object`.
+     */
+    function getMatchData(object) {
+      var result = pairs(object),
+          length = result.length;
+
+      while (length--) {
+        result[length][2] = isStrictComparable(result[length][1]);
+      }
       return result;
     }
 
     /**
-     * Checks if `value` is a native function.
+     * Gets the native function at `key` of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {string} key The key of the method to get.
+     * @returns {*} Returns the function if it's native, else `undefined`.
+     */
+    function getNative(object, key) {
+      var value = object == null ? undefined : object[key];
+      return isNative(value) ? value : undefined;
+    }
+
+    /**
+     * Gets the view, applying any `transforms` to the `start` and `end` positions.
+     *
+     * @private
+     * @param {number} start The start of the view.
+     * @param {number} end The end of the view.
+     * @param {Array} transforms The transformations to apply to the view.
+     * @returns {Object} Returns an object containing the `start` and `end`
+     *  positions of the view.
+     */
+    function getView(start, end, transforms) {
+      var index = -1,
+          length = transforms.length;
+
+      while (++index < length) {
+        var data = transforms[index],
+            size = data.size;
+
+        switch (data.type) {
+          case 'drop':      start += size; break;
+          case 'dropRight': end -= size; break;
+          case 'take':      end = nativeMin(end, start + size); break;
+          case 'takeRight': start = nativeMax(start, end - size); break;
+        }
+      }
+      return { 'start': start, 'end': end };
+    }
+
+    /**
+     * Initializes an array clone.
+     *
+     * @private
+     * @param {Array} array The array to clone.
+     * @returns {Array} Returns the initialized clone.
+     */
+    function initCloneArray(array) {
+      var length = array.length,
+          result = new array.constructor(length);
+
+      // Add array properties assigned by `RegExp#exec`.
+      if (length && typeof array[0] == 'string' && hasOwnProperty.call(array, 'index')) {
+        result.index = array.index;
+        result.input = array.input;
+      }
+      return result;
+    }
+
+    /**
+     * Initializes an object clone.
+     *
+     * @private
+     * @param {Object} object The object to clone.
+     * @returns {Object} Returns the initialized clone.
+     */
+    function initCloneObject(object) {
+      var Ctor = object.constructor;
+      if (!(typeof Ctor == 'function' && Ctor instanceof Ctor)) {
+        Ctor = Object;
+      }
+      return new Ctor;
+    }
+
+    /**
+     * Initializes an object clone based on its `toStringTag`.
+     *
+     * **Note:** This function only supports cloning values with tags of
+     * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
+     *
+     * @private
+     * @param {Object} object The object to clone.
+     * @param {string} tag The `toStringTag` of the object to clone.
+     * @param {boolean} [isDeep] Specify a deep clone.
+     * @returns {Object} Returns the initialized clone.
+     */
+    function initCloneByTag(object, tag, isDeep) {
+      var Ctor = object.constructor;
+      switch (tag) {
+        case arrayBufferTag:
+          return bufferClone(object);
+
+        case boolTag:
+        case dateTag:
+          return new Ctor(+object);
+
+        case float32Tag: case float64Tag:
+        case int8Tag: case int16Tag: case int32Tag:
+        case uint8Tag: case uint8ClampedTag: case uint16Tag: case uint32Tag:
+          var buffer = object.buffer;
+          return new Ctor(isDeep ? bufferClone(buffer) : buffer, object.byteOffset, object.length);
+
+        case numberTag:
+        case stringTag:
+          return new Ctor(object);
+
+        case regexpTag:
+          var result = new Ctor(object.source, reFlags.exec(object));
+          result.lastIndex = object.lastIndex;
+      }
+      return result;
+    }
+
+    /**
+     * Invokes the method at `path` on `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the method to invoke.
+     * @param {Array} args The arguments to invoke the method with.
+     * @returns {*} Returns the result of the invoked method.
+     */
+    function invokePath(object, path, args) {
+      if (object != null && !isKey(path, object)) {
+        path = toPath(path);
+        object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+        path = last(path);
+      }
+      var func = object == null ? object : object[path];
+      return func == null ? undefined : func.apply(object, args);
+    }
+
+    /**
+     * Checks if `value` is array-like.
      *
      * @private
      * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a native function, else `false`.
-     */
-    function isNative(value) {
-      return typeof value == 'function' && reNative.test(value);
-    }
-
-    /**
-     * Sets `this` binding data on a given function.
-     *
-     * @private
-     * @param {Function} func The function to set data on.
-     * @param {Array} value The data array to set.
-     */
-    var setBindData = !defineProperty ? noop : function(func, value) {
-      descriptor.value = value;
-      defineProperty(func, '__bindData__', descriptor);
-      descriptor.value = null;
-    };
-
-    /**
-     * A fallback implementation of `isPlainObject` which checks if a given value
-     * is an object created by the `Object` constructor, assuming objects created
-     * by the `Object` constructor have no inherited enumerable properties and that
-     * there are no `Object.prototype` extensions.
+     * @returns {boolean} Returns `true` if `value` is array-like, else `false`.
+     */
+    function isArrayLike(value) {
+      return value != null && isLength(getLength(value));
+    }
+
+    /**
+     * Checks if `value` is a valid array-like index.
      *
      * @private
      * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
-     */
-    function shimIsPlainObject(value) {
-      var ctor,
-          result;
-
-      // avoid non Object objects, `arguments` objects, and DOM elements
-      if (!(value && toString.call(value) == objectClass) ||
-          (ctor = value.constructor, isFunction(ctor) && !(ctor instanceof ctor))) {
-        return false;
-      }
-      // In most environments an object's own properties are iterated before
-      // its inherited properties. If the last iterated property is an object's
-      // own property then there are no inherited enumerable properties.
-      forIn(value, function(value, key) {
-        result = key;
-      });
-      return typeof result == 'undefined' || hasOwnProperty.call(value, result);
-    }
-
-    /**
-     * Used by `unescape` to convert HTML entities to characters.
-     *
-     * @private
-     * @param {string} match The matched character to unescape.
-     * @returns {string} Returns the unescaped character.
-     */
-    function unescapeHtmlChar(match) {
-      return htmlUnescapes[match];
-    }
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Checks if `value` is an `arguments` object.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is an `arguments` object, else `false`.
-     * @example
-     *
-     * (function() { return _.isArguments(arguments); })(1, 2, 3);
-     * // => true
-     *
-     * _.isArguments([1, 2, 3]);
-     * // => false
-     */
-    function isArguments(value) {
-      return value && typeof value == 'object' && typeof value.length == 'number' &&
-        toString.call(value) == argsClass || false;
-    }
-
-    /**
-     * Checks if `value` is an array.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is an array, else `false`.
-     * @example
-     *
-     * (function() { return _.isArray(arguments); })();
-     * // => false
-     *
-     * _.isArray([1, 2, 3]);
-     * // => true
-     */
-    var isArray = nativeIsArray || function(value) {
-      return value && typeof value == 'object' && typeof value.length == 'number' &&
-        toString.call(value) == arrayClass || false;
-    };
-
-    /**
-     * A fallback implementation of `Object.keys` which produces an array of the
-     * given object's own enumerable property names.
-     *
-     * @private
-     * @type Function
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property names.
-     */
-    var shimKeys = function(object) {
-      var index, iterable = object, result = [];
-      if (!iterable) return result;
-      if (!(objectTypes[typeof object])) return result;
-        for (index in iterable) {
-          if (hasOwnProperty.call(iterable, index)) {
-            result.push(index);
-          }
-        }
-      return result
-    };
-
-    /**
-     * Creates an array composed of the own enumerable property names of an object.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property names.
-     * @example
-     *
-     * _.keys({ 'one': 1, 'two': 2, 'three': 3 });
-     * // => ['one', 'two', 'three'] (property order is not guaranteed across environments)
-     */
-    var keys = !nativeKeys ? shimKeys : function(object) {
+     * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
+     * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
+     */
+    function isIndex(value, length) {
+      value = (typeof value == 'number' || reIsUint.test(value)) ? +value : -1;
+      length = length == null ? MAX_SAFE_INTEGER : length;
+      return value > -1 && value % 1 == 0 && value < length;
+    }
+
+    /**
+     * Checks if the provided arguments are from an iteratee call.
+     *
+     * @private
+     * @param {*} value The potential iteratee value argument.
+     * @param {*} index The potential iteratee index or key argument.
+     * @param {*} object The potential iteratee object argument.
+     * @returns {boolean} Returns `true` if the arguments are from an iteratee call, else `false`.
+     */
+    function isIterateeCall(value, index, object) {
       if (!isObject(object)) {
-        return [];
-      }
-      return nativeKeys(object);
-    };
-
-    /**
-     * Used to convert characters to HTML entities:
-     *
-     * Though the `>` character is escaped for symmetry, characters like `>` and `/`
-     * don't require escaping in HTML and have no special meaning unless they're part
-     * of a tag or an unquoted attribute value.
-     * http://mathiasbynens.be/notes/ambiguous-ampersands (under "semi-related fun fact")
-     */
-    var htmlEscapes = {
-      '&': '&amp;',
-      '<': '&lt;',
-      '>': '&gt;',
-      '"': '&quot;',
-      "'": '&#39;'
-    };
-
-    /** Used to convert HTML entities to characters */
-    var htmlUnescapes = invert(htmlEscapes);
-
-    /** Used to match HTML entities and HTML characters */
-    var reEscapedHtml = RegExp('(' + keys(htmlUnescapes).join('|') + ')', 'g'),
-        reUnescapedHtml = RegExp('[' + keys(htmlEscapes).join('') + ']', 'g');
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Assigns own enumerable properties of source object(s) to the destination
-     * object. Subsequent sources will overwrite property assignments of previous
-     * sources. If a callback is provided it will be executed to produce the
-     * assigned values. The callback is bound to `thisArg` and invoked with two
-     * arguments; (objectValue, sourceValue).
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @alias extend
-     * @category Objects
-     * @param {Object} object The destination object.
-     * @param {...Object} [source] The source objects.
-     * @param {Function} [callback] The function to customize assigning values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns the destination object.
-     * @example
-     *
-     * _.assign({ 'name': 'fred' }, { 'employer': 'slate' });
-     * // => { 'name': 'fred', 'employer': 'slate' }
-     *
-     * var defaults = _.partialRight(_.assign, function(a, b) {
-     *   return typeof a == 'undefined' ? b : a;
-     * });
-     *
-     * var object = { 'name': 'barney' };
-     * defaults(object, { 'name': 'fred', 'employer': 'slate' });
-     * // => { 'name': 'barney', 'employer': 'slate' }
-     */
-    var assign = function(object, source, guard) {
-      var index, iterable = object, result = iterable;
-      if (!iterable) return result;
-      var args = arguments,
-          argsIndex = 0,
-          argsLength = typeof guard == 'number' ? 2 : args.length;
-      if (argsLength > 3 && typeof args[argsLength - 2] == 'function') {
-        var callback = baseCreateCallback(args[--argsLength - 1], args[argsLength--], 2);
-      } else if (argsLength > 2 && typeof args[argsLength - 1] == 'function') {
-        callback = args[--argsLength];
-      }
-      while (++argsIndex < argsLength) {
-        iterable = args[argsIndex];
-        if (iterable && objectTypes[typeof iterable]) {
-        var ownIndex = -1,
-            ownProps = objectTypes[typeof iterable] && keys(iterable),
-            length = ownProps ? ownProps.length : 0;
-
-        while (++ownIndex < length) {
-          index = ownProps[ownIndex];
-          result[index] = callback ? callback(result[index], iterable[index]) : iterable[index];
-        }
-        }
-      }
-      return result
-    };
-
-    /**
-     * Creates a clone of `value`. If `isDeep` is `true` nested objects will also
-     * be cloned, otherwise they will be assigned by reference. If a callback
-     * is provided it will be executed to produce the cloned values. If the
-     * callback returns `undefined` cloning will be handled by the method instead.
-     * The callback is bound to `thisArg` and invoked with one argument; (value).
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to clone.
-     * @param {boolean} [isDeep=false] Specify a deep clone.
-     * @param {Function} [callback] The function to customize cloning values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the cloned value.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
-     *
-     * var shallow = _.clone(characters);
-     * shallow[0] === characters[0];
-     * // => true
-     *
-     * var deep = _.clone(characters, true);
-     * deep[0] === characters[0];
-     * // => false
-     *
-     * _.mixin({
-     *   'clone': _.partialRight(_.clone, function(value) {
-     *     return _.isElement(value) ? value.cloneNode(false) : undefined;
-     *   })
-     * });
-     *
-     * var clone = _.clone(document.body);
-     * clone.childNodes.length;
-     * // => 0
-     */
-    function clone(value, isDeep, callback, thisArg) {
-      // allows working with "Collections" methods without using their `index`
-      // and `collection` arguments for `isDeep` and `callback`
-      if (typeof isDeep != 'boolean' && isDeep != null) {
-        thisArg = callback;
-        callback = isDeep;
-        isDeep = false;
-      }
-      return baseClone(value, isDeep, typeof callback == 'function' && baseCreateCallback(callback, thisArg, 1));
-    }
-
-    /**
-     * Creates a deep clone of `value`. If a callback is provided it will be
-     * executed to produce the cloned values. If the callback returns `undefined`
-     * cloning will be handled by the method instead. The callback is bound to
-     * `thisArg` and invoked with one argument; (value).
-     *
-     * Note: This method is loosely based on the structured clone algorithm. Functions
-     * and DOM nodes are **not** cloned. The enumerable properties of `arguments` objects and
-     * objects created by constructors other than `Object` are cloned to plain `Object` objects.
-     * See http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to deep clone.
-     * @param {Function} [callback] The function to customize cloning values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the deep cloned value.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
-     *
-     * var deep = _.cloneDeep(characters);
-     * deep[0] === characters[0];
-     * // => false
-     *
-     * var view = {
-     *   'label': 'docs',
-     *   'node': element
-     * };
-     *
-     * var clone = _.cloneDeep(view, function(value) {
-     *   return _.isElement(value) ? value.cloneNode(true) : undefined;
-     * });
-     *
-     * clone.node == view.node;
-     * // => false
-     */
-    function cloneDeep(value, callback, thisArg) {
-      return baseClone(value, true, typeof callback == 'function' && baseCreateCallback(callback, thisArg, 1));
-    }
-
-    /**
-     * Creates an object that inherits from the given `prototype` object. If a
-     * `properties` object is provided its own enumerable properties are assigned
-     * to the created object.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} prototype The object to inherit from.
-     * @param {Object} [properties] The properties to assign to the object.
+        return false;
+      }
+      var type = typeof index;
+      if (type == 'number'
+          ? (isArrayLike(object) && isIndex(index, object.length))
+          : (type == 'string' && index in object)) {
+        var other = object[index];
+        return value === value ? (value === other) : (other !== other);
+      }
+      return false;
+    }
+
+    /**
+     * Checks if `value` is a property name and not a property path.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @param {Object} [object] The object to query keys on.
+     * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
+     */
+    function isKey(value, object) {
+      var type = typeof value;
+      if ((type == 'string' && reIsPlainProp.test(value)) || type == 'number') {
+        return true;
+      }
+      if (isArray(value)) {
+        return false;
+      }
+      var result = !reIsDeepProp.test(value);
+      return result || (object != null && value in toObject(object));
+    }
+
+    /**
+     * Checks if `func` has a lazy counterpart.
+     *
+     * @private
+     * @param {Function} func The function to check.
+     * @returns {boolean} Returns `true` if `func` has a lazy counterpart, else `false`.
+     */
+    function isLaziable(func) {
+      var funcName = getFuncName(func),
+          other = lodash[funcName];
+
+      if (typeof other != 'function' || !(funcName in LazyWrapper.prototype)) {
+        return false;
+      }
+      if (func === other) {
+        return true;
+      }
+      var data = getData(other);
+      return !!data && func === data[0];
+    }
+
+    /**
+     * Checks if `value` is a valid array-like length.
+     *
+     * **Note:** This function is based on [`ToLength`](http://ecma-international.org/ecma-262/6.0/#sec-tolength).
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a valid length, else `false`.
+     */
+    function isLength(value) {
+      return typeof value == 'number' && value > -1 && value % 1 == 0 && value <= MAX_SAFE_INTEGER;
+    }
+
+    /**
+     * Checks if `value` is suitable for strict equality comparisons, i.e. `===`.
+     *
+     * @private
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` if suitable for strict
+     *  equality comparisons, else `false`.
+     */
+    function isStrictComparable(value) {
+      return value === value && !isObject(value);
+    }
+
+    /**
+     * Merges the function metadata of `source` into `data`.
+     *
+     * Merging metadata reduces the number of wrappers required to invoke a function.
+     * This is possible because methods like `_.bind`, `_.curry`, and `_.partial`
+     * may be applied regardless of execution order. Methods like `_.ary` and `_.rearg`
+     * augment function arguments, making the order in which they are executed important,
+     * preventing the merging of metadata. However, we make an exception for a safe
+     * common case where curried functions have `_.ary` and or `_.rearg` applied.
+     *
+     * @private
+     * @param {Array} data The destination metadata.
+     * @param {Array} source The source metadata.
+     * @returns {Array} Returns `data`.
+     */
+    function mergeData(data, source) {
+      var bitmask = data[1],
+          srcBitmask = source[1],
+          newBitmask = bitmask | srcBitmask,
+          isCommon = newBitmask < ARY_FLAG;
+
+      var isCombo =
+        (srcBitmask == ARY_FLAG && bitmask == CURRY_FLAG) ||
+        (srcBitmask == ARY_FLAG && bitmask == REARG_FLAG && data[7].length <= source[8]) ||
+        (srcBitmask == (ARY_FLAG | REARG_FLAG) && bitmask == CURRY_FLAG);
+
+      // Exit early if metadata can't be merged.
+      if (!(isCommon || isCombo)) {
+        return data;
+      }
+      // Use source `thisArg` if available.
+      if (srcBitmask & BIND_FLAG) {
+        data[2] = source[2];
+        // Set when currying a bound function.
+        newBitmask |= (bitmask & BIND_FLAG) ? 0 : CURRY_BOUND_FLAG;
+      }
+      // Compose partial arguments.
+      var value = source[3];
+      if (value) {
+        var partials = data[3];
+        data[3] = partials ? composeArgs(partials, value, source[4]) : arrayCopy(value);
+        data[4] = partials ? replaceHolders(data[3], PLACEHOLDER) : arrayCopy(source[4]);
+      }
+      // Compose partial right arguments.
+      value = source[5];
+      if (value) {
+        partials = data[5];
+        data[5] = partials ? composeArgsRight(partials, value, source[6]) : arrayCopy(value);
+        data[6] = partials ? replaceHolders(data[5], PLACEHOLDER) : arrayCopy(source[6]);
+      }
+      // Use source `argPos` if available.
+      value = source[7];
+      if (value) {
+        data[7] = arrayCopy(value);
+      }
+      // Use source `ary` if it's smaller.
+      if (srcBitmask & ARY_FLAG) {
+        data[8] = data[8] == null ? source[8] : nativeMin(data[8], source[8]);
+      }
+      // Use source `arity` if one is not provided.
+      if (data[9] == null) {
+        data[9] = source[9];
+      }
+      // Use source `func` and merge bitmasks.
+      data[0] = source[0];
+      data[1] = newBitmask;
+
+      return data;
+    }
+
+    /**
+     * Used by `_.defaultsDeep` to customize its `_.merge` use.
+     *
+     * @private
+     * @param {*} objectValue The destination object property value.
+     * @param {*} sourceValue The source object property value.
+     * @returns {*} Returns the value to assign to the destination object.
+     */
+    function mergeDefaults(objectValue, sourceValue) {
+      return objectValue === undefined ? sourceValue : merge(objectValue, sourceValue, mergeDefaults);
+    }
+
+    /**
+     * A specialized version of `_.pick` which picks `object` properties specified
+     * by `props`.
+     *
+     * @private
+     * @param {Object} object The source object.
+     * @param {string[]} props The property names to pick.
      * @returns {Object} Returns the new object.
-     * @example
-     *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
-     *
-     * function Circle() {
-     *   Shape.call(this);
-     * }
-     *
-     * Circle.prototype = _.create(Shape.prototype, { 'constructor': Circle });
-     *
-     * var circle = new Circle;
-     * circle instanceof Circle;
-     * // => true
-     *
-     * circle instanceof Shape;
-     * // => true
-     */
-    function create(prototype, properties) {
-      var result = baseCreate(prototype);
-      return properties ? assign(result, properties) : result;
-    }
-
-    /**
-     * Assigns own enumerable properties of source object(s) to the destination
-     * object for all destination properties that resolve to `undefined`. Once a
-     * property is set, additional defaults of the same property will be ignored.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {Object} object The destination object.
-     * @param {...Object} [source] The source objects.
-     * @param- {Object} [guard] Allows working with `_.reduce` without using its
-     *  `key` and `object` arguments as sources.
-     * @returns {Object} Returns the destination object.
-     * @example
-     *
-     * var object = { 'name': 'barney' };
-     * _.defaults(object, { 'name': 'fred', 'employer': 'slate' });
-     * // => { 'name': 'barney', 'employer': 'slate' }
-     */
-    var defaults = function(object, source, guard) {
-      var index, iterable = object, result = iterable;
-      if (!iterable) return result;
-      var args = arguments,
-          argsIndex = 0,
-          argsLength = typeof guard == 'number' ? 2 : args.length;
-      while (++argsIndex < argsLength) {
-        iterable = args[argsIndex];
-        if (iterable && objectTypes[typeof iterable]) {
-        var ownIndex = -1,
-            ownProps = objectTypes[typeof iterable] && keys(iterable),
-            length = ownProps ? ownProps.length : 0;
-
-        while (++ownIndex < length) {
-          index = ownProps[ownIndex];
-          if (typeof result[index] == 'undefined') result[index] = iterable[index];
-        }
-        }
-      }
-      return result
-    };
-
-    /**
-     * This method is like `_.findIndex` except that it returns the key of the
-     * first element that passes the callback check, instead of the element itself.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to search.
-     * @param {Function|Object|string} [callback=identity] The function called per
-     *  iteration. If a property name or object is provided it will be used to
-     *  create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {string|undefined} Returns the key of the found element, else `undefined`.
-     * @example
-     *
-     * var characters = {
-     *   'barney': {  'age': 36, 'blocked': false },
-     *   'fred': {    'age': 40, 'blocked': true },
-     *   'pebbles': { 'age': 1,  'blocked': false }
-     * };
-     *
-     * _.findKey(characters, function(chr) {
-     *   return chr.age < 40;
-     * });
-     * // => 'barney' (property order is not guaranteed across environments)
-     *
-     * // using "_.where" callback shorthand
-     * _.findKey(characters, { 'age': 1 });
-     * // => 'pebbles'
-     *
-     * // using "_.pluck" callback shorthand
-     * _.findKey(characters, 'blocked');
-     * // => 'fred'
-     */
-    function findKey(object, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      forOwn(object, function(value, key, object) {
-        if (callback(value, key, object)) {
-          result = key;
-          return false;
-        }
-      });
-      return result;
-    }
-
-    /**
-     * This method is like `_.findKey` except that it iterates over elements
-     * of a `collection` in the opposite order.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to search.
-     * @param {Function|Object|string} [callback=identity] The function called per
-     *  iteration. If a property name or object is provided it will be used to
-     *  create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {string|undefined} Returns the key of the found element, else `undefined`.
-     * @example
-     *
-     * var characters = {
-     *   'barney': {  'age': 36, 'blocked': true },
-     *   'fred': {    'age': 40, 'blocked': false },
-     *   'pebbles': { 'age': 1,  'blocked': true }
-     * };
-     *
-     * _.findLastKey(characters, function(chr) {
-     *   return chr.age < 40;
-     * });
-     * // => returns `pebbles`, assuming `_.findKey` returns `barney`
-     *
-     * // using "_.where" callback shorthand
-     * _.findLastKey(characters, { 'age': 40 });
-     * // => 'fred'
-     *
-     * // using "_.pluck" callback shorthand
-     * _.findLastKey(characters, 'blocked');
-     * // => 'pebbles'
-     */
-    function findLastKey(object, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      forOwnRight(object, function(value, key, object) {
-        if (callback(value, key, object)) {
-          result = key;
-          return false;
-        }
-      });
-      return result;
-    }
-
-    /**
-     * Iterates over own and inherited enumerable properties of an object,
-     * executing the callback for each property. The callback is bound to `thisArg`
-     * and invoked with three arguments; (value, key, object). Callbacks may exit
-     * iteration early by explicitly returning `false`.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
-     * @example
-     *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
-     *
-     * Shape.prototype.move = function(x, y) {
-     *   this.x += x;
-     *   this.y += y;
-     * };
-     *
-     * _.forIn(new Shape, function(value, key) {
-     *   console.log(key);
-     * });
-     * // => logs 'x', 'y', and 'move' (property order is not guaranteed across environments)
-     */
-    var forIn = function(collection, callback, thisArg) {
-      var index, iterable = collection, result = iterable;
-      if (!iterable) return result;
-      if (!objectTypes[typeof iterable]) return result;
-      callback = callback && typeof thisArg == 'undefined' ? callback : baseCreateCallback(callback, thisArg, 3);
-        for (index in iterable) {
-          if (callback(iterable[index], index, collection) === false) return result;
-        }
-      return result
-    };
-
-    /**
-     * This method is like `_.forIn` except that it iterates over elements
-     * of a `collection` in the opposite order.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
-     * @example
-     *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
-     *
-     * Shape.prototype.move = function(x, y) {
-     *   this.x += x;
-     *   this.y += y;
-     * };
-     *
-     * _.forInRight(new Shape, function(value, key) {
-     *   console.log(key);
-     * });
-     * // => logs 'move', 'y', and 'x' assuming `_.forIn ` logs 'x', 'y', and 'move'
-     */
-    function forInRight(object, callback, thisArg) {
-      var pairs = [];
-
-      forIn(object, function(value, key) {
-        pairs.push(key, value);
-      });
-
-      var length = pairs.length;
-      callback = baseCreateCallback(callback, thisArg, 3);
-      while (length--) {
-        if (callback(pairs[length--], pairs[length], object) === false) {
-          break;
-        }
-      }
-      return object;
-    }
-
-    /**
-     * Iterates over own enumerable properties of an object, executing the callback
-     * for each property. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, key, object). Callbacks may exit iteration early by
-     * explicitly returning `false`.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
-     * @example
-     *
-     * _.forOwn({ '0': 'zero', '1': 'one', 'length': 2 }, function(num, key) {
-     *   console.log(key);
-     * });
-     * // => logs '0', '1', and 'length' (property order is not guaranteed across environments)
-     */
-    var forOwn = function(collection, callback, thisArg) {
-      var index, iterable = collection, result = iterable;
-      if (!iterable) return result;
-      if (!objectTypes[typeof iterable]) return result;
-      callback = callback && typeof thisArg == 'undefined' ? callback : baseCreateCallback(callback, thisArg, 3);
-        var ownIndex = -1,
-            ownProps = objectTypes[typeof iterable] && keys(iterable),
-            length = ownProps ? ownProps.length : 0;
-
-        while (++ownIndex < length) {
-          index = ownProps[ownIndex];
-          if (callback(iterable[index], index, collection) === false) return result;
-        }
-      return result
-    };
-
-    /**
-     * This method is like `_.forOwn` except that it iterates over elements
-     * of a `collection` in the opposite order.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns `object`.
-     * @example
-     *
-     * _.forOwnRight({ '0': 'zero', '1': 'one', 'length': 2 }, function(num, key) {
-     *   console.log(key);
-     * });
-     * // => logs 'length', '1', and '0' assuming `_.forOwn` logs '0', '1', and 'length'
-     */
-    function forOwnRight(object, callback, thisArg) {
-      var props = keys(object),
-          length = props.length;
-
-      callback = baseCreateCallback(callback, thisArg, 3);
-      while (length--) {
-        var key = props[length];
-        if (callback(object[key], key, object) === false) {
-          break;
-        }
-      }
-      return object;
-    }
-
-    /**
-     * Creates a sorted array of property names of all enumerable properties,
-     * own and inherited, of `object` that have function values.
-     *
-     * @static
-     * @memberOf _
-     * @alias methods
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property names that have function values.
-     * @example
-     *
-     * _.functions(_);
-     * // => ['all', 'any', 'bind', 'bindAll', 'clone', 'compact', 'compose', ...]
-     */
-    function functions(object) {
-      var result = [];
-      forIn(object, function(value, key) {
-        if (isFunction(value)) {
-          result.push(key);
-        }
-      });
-      return result.sort();
-    }
-
-    /**
-     * Checks if the specified property name exists as a direct property of `object`,
-     * instead of an inherited property.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @param {string} key The name of the property to check.
-     * @returns {boolean} Returns `true` if key is a direct property, else `false`.
-     * @example
-     *
-     * _.has({ 'a': 1, 'b': 2, 'c': 3 }, 'b');
-     * // => true
-     */
-    function has(object, key) {
-      return object ? hasOwnProperty.call(object, key) : false;
-    }
-
-    /**
-     * Creates an object composed of the inverted keys and values of the given object.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to invert.
-     * @returns {Object} Returns the created inverted object.
-     * @example
-     *
-     * _.invert({ 'first': 'fred', 'second': 'barney' });
-     * // => { 'fred': 'first', 'barney': 'second' }
-     */
-    function invert(object) {
+     */
+    function pickByArray(object, props) {
+      object = toObject(object);
+
       var index = -1,
-          props = keys(object),
           length = props.length,
           result = {};
 
       while (++index < length) {
         var key = props[index];
-        result[object[key]] = key;
+        if (key in object) {
+          result[key] = object[key];
+        }
       }
       return result;
     }
 
     /**
-     * Checks if `value` is a boolean value.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a boolean value, else `false`.
-     * @example
-     *
-     * _.isBoolean(null);
-     * // => false
-     */
-    function isBoolean(value) {
-      return value === true || value === false ||
-        value && typeof value == 'object' && toString.call(value) == boolClass || false;
-    }
-
-    /**
-     * Checks if `value` is a date.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a date, else `false`.
-     * @example
-     *
-     * _.isDate(new Date);
-     * // => true
-     */
-    function isDate(value) {
-      return value && typeof value == 'object' && toString.call(value) == dateClass || false;
-    }
-
-    /**
-     * Checks if `value` is a DOM element.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a DOM element, else `false`.
-     * @example
-     *
-     * _.isElement(document.body);
-     * // => true
-     */
-    function isElement(value) {
-      return value && value.nodeType === 1 || false;
-    }
-
-    /**
-     * Checks if `value` is empty. Arrays, strings, or `arguments` objects with a
-     * length of `0` and objects with no own enumerable properties are considered
-     * "empty".
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Array|Object|string} value The value to inspect.
-     * @returns {boolean} Returns `true` if the `value` is empty, else `false`.
-     * @example
-     *
-     * _.isEmpty([1, 2, 3]);
-     * // => false
-     *
-     * _.isEmpty({});
-     * // => true
-     *
-     * _.isEmpty('');
-     * // => true
-     */
-    function isEmpty(value) {
-      var result = true;
-      if (!value) {
-        return result;
-      }
-      var className = toString.call(value),
-          length = value.length;
-
-      if ((className == arrayClass || className == stringClass || className == argsClass ) ||
-          (className == objectClass && typeof length == 'number' && isFunction(value.splice))) {
-        return !length;
-      }
-      forOwn(value, function() {
-        return (result = false);
+     * A specialized version of `_.pick` which picks `object` properties `predicate`
+     * returns truthy for.
+     *
+     * @private
+     * @param {Object} object The source object.
+     * @param {Function} predicate The function invoked per iteration.
+     * @returns {Object} Returns the new object.
+     */
+    function pickByCallback(object, predicate) {
+      var result = {};
+      baseForIn(object, function(value, key, object) {
+        if (predicate(value, key, object)) {
+          result[key] = value;
+        }
+      });
+      return result;
+    }
+
+    /**
+     * Reorder `array` according to the specified indexes where the element at
+     * the first index is assigned as the first element, the element at
+     * the second index is assigned as the second element, and so on.
+     *
+     * @private
+     * @param {Array} array The array to reorder.
+     * @param {Array} indexes The arranged array indexes.
+     * @returns {Array} Returns `array`.
+     */
+    function reorder(array, indexes) {
+      var arrLength = array.length,
+          length = nativeMin(indexes.length, arrLength),
+          oldArray = arrayCopy(array);
+
+      while (length--) {
+        var index = indexes[length];
+        array[length] = isIndex(index, arrLength) ? oldArray[index] : undefined;
+      }
+      return array;
+    }
+
+    /**
+     * Sets metadata for `func`.
+     *
+     * **Note:** If this function becomes hot, i.e. is invoked a lot in a short
+     * period of time, it will trip its breaker and transition to an identity function
+     * to avoid garbage collection pauses in V8. See [V8 issue 2070](https://code.google.com/p/v8/issues/detail?id=2070)
+     * for more details.
+     *
+     * @private
+     * @param {Function} func The function to associate metadata with.
+     * @param {*} data The metadata.
+     * @returns {Function} Returns `func`.
+     */
+    var setData = (function() {
+      var count = 0,
+          lastCalled = 0;
+
+      return function(key, value) {
+        var stamp = now(),
+            remaining = HOT_SPAN - (stamp - lastCalled);
+
+        lastCalled = stamp;
+        if (remaining > 0) {
+          if (++count >= HOT_COUNT) {
+            return key;
+          }
+        } else {
+          count = 0;
+        }
+        return baseSetData(key, value);
+      };
+    }());
+
+    /**
+     * A fallback implementation of `Object.keys` which creates an array of the
+     * own enumerable property names of `object`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names.
+     */
+    function shimKeys(object) {
+      var props = keysIn(object),
+          propsLength = props.length,
+          length = propsLength && object.length;
+
+      var allowIndexes = !!length && isLength(length) &&
+        (isArray(object) || isArguments(object));
+
+      var index = -1,
+          result = [];
+
+      while (++index < propsLength) {
+        var key = props[index];
+        if ((allowIndexes && isIndex(key, length)) || hasOwnProperty.call(object, key)) {
+          result.push(key);
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Converts `value` to an array-like object if it's not one.
+     *
+     * @private
+     * @param {*} value The value to process.
+     * @returns {Array|Object} Returns the array-like object.
+     */
+    function toIterable(value) {
+      if (value == null) {
+        return [];
+      }
+      if (!isArrayLike(value)) {
+        return values(value);
+      }
+      return isObject(value) ? value : Object(value);
+    }
+
+    /**
+     * Converts `value` to an object if it's not one.
+     *
+     * @private
+     * @param {*} value The value to process.
+     * @returns {Object} Returns the object.
+     */
+    function toObject(value) {
+      return isObject(value) ? value : Object(value);
+    }
+
+    /**
+     * Converts `value` to property path array if it's not one.
+     *
+     * @private
+     * @param {*} value The value to process.
+     * @returns {Array} Returns the property path array.
+     */
+    function toPath(value) {
+      if (isArray(value)) {
+        return value;
+      }
+      var result = [];
+      baseToString(value).replace(rePropName, function(match, number, quote, string) {
+        result.push(quote ? string.replace(reEscapeChar, '$1') : (number || match));
       });
       return result;
     }
 
     /**
-     * Performs a deep comparison between two values to determine if they are
-     * equivalent to each other. If a callback is provided it will be executed
-     * to compare values. If the callback returns `undefined` comparisons will
-     * be handled by the method instead. The callback is bound to `thisArg` and
-     * invoked with two arguments; (a, b).
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} a The value to compare.
-     * @param {*} b The other value to compare.
-     * @param {Function} [callback] The function to customize comparing values.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
-     * @example
-     *
-     * var object = { 'name': 'fred' };
-     * var copy = { 'name': 'fred' };
-     *
-     * object == copy;
-     * // => false
-     *
-     * _.isEqual(object, copy);
-     * // => true
-     *
-     * var words = ['hello', 'goodbye'];
-     * var otherWords = ['hi', 'goodbye'];
-     *
-     * _.isEqual(words, otherWords, function(a, b) {
-     *   var reGreet = /^(?:hello|hi)$/i,
-     *       aGreet = _.isString(a) && reGreet.test(a),
-     *       bGreet = _.isString(b) && reGreet.test(b);
-     *
-     *   return (aGreet || bGreet) ? (aGreet == bGreet) : undefined;
+     * Creates a clone of `wrapper`.
+     *
+     * @private
+     * @param {Object} wrapper The wrapper to clone.
+     * @returns {Object} Returns the cloned wrapper.
+     */
+    function wrapperClone(wrapper) {
+      return wrapper instanceof LazyWrapper
+        ? wrapper.clone()
+        : new LodashWrapper(wrapper.__wrapped__, wrapper.__chain__, arrayCopy(wrapper.__actions__));
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates an array of elements split into groups the length of `size`.
+     * If `collection` can't be split evenly, the final chunk will be the remaining
+     * elements.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to process.
+     * @param {number} [size=1] The length of each chunk.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the new array containing chunks.
+     * @example
+     *
+     * _.chunk(['a', 'b', 'c', 'd'], 2);
+     * // => [['a', 'b'], ['c', 'd']]
+     *
+     * _.chunk(['a', 'b', 'c', 'd'], 3);
+     * // => [['a', 'b', 'c'], ['d']]
+     */
+    function chunk(array, size, guard) {
+      if (guard ? isIterateeCall(array, size, guard) : size == null) {
+        size = 1;
+      } else {
+        size = nativeMax(nativeFloor(size) || 1, 1);
+      }
+      var index = 0,
+          length = array ? array.length : 0,
+          resIndex = -1,
+          result = Array(nativeCeil(length / size));
+
+      while (index < length) {
+        result[++resIndex] = baseSlice(array, index, (index += size));
+      }
+      return result;
+    }
+
+    /**
+     * Creates an array with all falsey values removed. The values `false`, `null`,
+     * `0`, `""`, `undefined`, and `NaN` are falsey.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to compact.
+     * @returns {Array} Returns the new array of filtered values.
+     * @example
+     *
+     * _.compact([0, 1, false, 2, '', 3]);
+     * // => [1, 2, 3]
+     */
+    function compact(array) {
+      var index = -1,
+          length = array ? array.length : 0,
+          resIndex = -1,
+          result = [];
+
+      while (++index < length) {
+        var value = array[index];
+        if (value) {
+          result[++resIndex] = value;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Creates an array of unique `array` values not included in the other
+     * provided arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {...Array} [values] The arrays of values to exclude.
+     * @returns {Array} Returns the new array of filtered values.
+     * @example
+     *
+     * _.difference([1, 2, 3], [4, 2]);
+     * // => [1, 3]
+     */
+    var difference = restParam(function(array, values) {
+      return (isObjectLike(array) && isArrayLike(array))
+        ? baseDifference(array, baseFlatten(values, false, true))
+        : [];
+    });
+
+    /**
+     * Creates a slice of `array` with `n` elements dropped from the beginning.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to drop.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.drop([1, 2, 3]);
+     * // => [2, 3]
+     *
+     * _.drop([1, 2, 3], 2);
+     * // => [3]
+     *
+     * _.drop([1, 2, 3], 5);
+     * // => []
+     *
+     * _.drop([1, 2, 3], 0);
+     * // => [1, 2, 3]
+     */
+    function drop(array, n, guard) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (guard ? isIterateeCall(array, n, guard) : n == null) {
+        n = 1;
+      }
+      return baseSlice(array, n < 0 ? 0 : n);
+    }
+
+    /**
+     * Creates a slice of `array` with `n` elements dropped from the end.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to drop.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.dropRight([1, 2, 3]);
+     * // => [1, 2]
+     *
+     * _.dropRight([1, 2, 3], 2);
+     * // => [1]
+     *
+     * _.dropRight([1, 2, 3], 5);
+     * // => []
+     *
+     * _.dropRight([1, 2, 3], 0);
+     * // => [1, 2, 3]
+     */
+    function dropRight(array, n, guard) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (guard ? isIterateeCall(array, n, guard) : n == null) {
+        n = 1;
+      }
+      n = length - (+n || 0);
+      return baseSlice(array, 0, n < 0 ? 0 : n);
+    }
+
+    /**
+     * Creates a slice of `array` excluding elements dropped from the end.
+     * Elements are dropped until `predicate` returns falsey. The predicate is
+     * bound to `thisArg` and invoked with three arguments: (value, index, array).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that match the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.dropRightWhile([1, 2, 3], function(n) {
+     *   return n > 1;
+     * });
+     * // => [1]
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': true },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': false }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.dropRightWhile(users, { 'user': 'pebbles', 'active': false }), 'user');
+     * // => ['barney', 'fred']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.dropRightWhile(users, 'active', false), 'user');
+     * // => ['barney']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.dropRightWhile(users, 'active'), 'user');
+     * // => ['barney', 'fred', 'pebbles']
+     */
+    function dropRightWhile(array, predicate, thisArg) {
+      return (array && array.length)
+        ? baseWhile(array, getCallback(predicate, thisArg, 3), true, true)
+        : [];
+    }
+
+    /**
+     * Creates a slice of `array` excluding elements dropped from the beginning.
+     * Elements are dropped until `predicate` returns falsey. The predicate is
+     * bound to `thisArg` and invoked with three arguments: (value, index, array).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.dropWhile([1, 2, 3], function(n) {
+     *   return n < 3;
      * });
-     * // => true
-     */
-    function isEqual(a, b, callback, thisArg) {
-      return baseIsEqual(a, b, typeof callback == 'function' && baseCreateCallback(callback, thisArg, 2));
-    }
-
-    /**
-     * Checks if `value` is, or can be coerced to, a finite number.
-     *
-     * Note: This is not the same as native `isFinite` which will return true for
-     * booleans and empty strings. See http://es5.github.io/#x15.1.2.5.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is finite, else `false`.
-     * @example
-     *
-     * _.isFinite(-101);
-     * // => true
-     *
-     * _.isFinite('10');
-     * // => true
-     *
-     * _.isFinite(true);
-     * // => false
-     *
-     * _.isFinite('');
-     * // => false
-     *
-     * _.isFinite(Infinity);
-     * // => false
-     */
-    function isFinite(value) {
-      return nativeIsFinite(value) && !nativeIsNaN(parseFloat(value));
-    }
-
-    /**
-     * Checks if `value` is a function.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a function, else `false`.
-     * @example
-     *
-     * _.isFunction(_);
-     * // => true
-     */
-    function isFunction(value) {
-      return typeof value == 'function';
-    }
-
-    /**
-     * Checks if `value` is the language type of Object.
-     * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is an object, else `false`.
-     * @example
-     *
-     * _.isObject({});
-     * // => true
-     *
-     * _.isObject([1, 2, 3]);
-     * // => true
-     *
-     * _.isObject(1);
-     * // => false
-     */
-    function isObject(value) {
-      // check if the value is the ECMAScript language type of Object
-      // http://es5.github.io/#x8
-      // and avoid a V8 bug
-      // http://code.google.com/p/v8/issues/detail?id=2291
-      return !!(value && objectTypes[typeof value]);
-    }
-
-    /**
-     * Checks if `value` is `NaN`.
-     *
-     * Note: This is not the same as native `isNaN` which will return `true` for
-     * `undefined` and other non-numeric values. See http://es5.github.io/#x15.1.2.4.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is `NaN`, else `false`.
-     * @example
-     *
-     * _.isNaN(NaN);
-     * // => true
-     *
-     * _.isNaN(new Number(NaN));
-     * // => true
-     *
-     * isNaN(undefined);
-     * // => true
-     *
-     * _.isNaN(undefined);
-     * // => false
-     */
-    function isNaN(value) {
-      // `NaN` as a primitive is the only value that is not equal to itself
-      // (perform the [[Class]] check first to avoid errors with some host objects in IE)
-      return isNumber(value) && value != +value;
-    }
-
-    /**
-     * Checks if `value` is `null`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is `null`, else `false`.
-     * @example
-     *
-     * _.isNull(null);
-     * // => true
-     *
-     * _.isNull(undefined);
-     * // => false
-     */
-    function isNull(value) {
-      return value === null;
-    }
-
-    /**
-     * Checks if `value` is a number.
-     *
-     * Note: `NaN` is considered a number. See http://es5.github.io/#x8.5.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a number, else `false`.
-     * @example
-     *
-     * _.isNumber(8.4 * 5);
-     * // => true
-     */
-    function isNumber(value) {
-      return typeof value == 'number' ||
-        value && typeof value == 'object' && toString.call(value) == numberClass || false;
-    }
-
-    /**
-     * Checks if `value` is an object created by the `Object` constructor.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
-     * @example
-     *
-     * function Shape() {
-     *   this.x = 0;
-     *   this.y = 0;
-     * }
-     *
-     * _.isPlainObject(new Shape);
-     * // => false
-     *
-     * _.isPlainObject([1, 2, 3]);
-     * // => false
-     *
-     * _.isPlainObject({ 'x': 0, 'y': 0 });
-     * // => true
-     */
-    var isPlainObject = !getPrototypeOf ? shimIsPlainObject : function(value) {
-      if (!(value && toString.call(value) == objectClass)) {
-        return false;
-      }
-      var valueOf = value.valueOf,
-          objProto = isNative(valueOf) && (objProto = getPrototypeOf(valueOf)) && getPrototypeOf(objProto);
-
-      return objProto
-        ? (value == objProto || getPrototypeOf(value) == objProto)
-        : shimIsPlainObject(value);
-    };
-
-    /**
-     * Checks if `value` is a regular expression.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a regular expression, else `false`.
-     * @example
-     *
-     * _.isRegExp(/fred/);
-     * // => true
-     */
-    function isRegExp(value) {
-      return value && typeof value == 'object' && toString.call(value) == regexpClass || false;
-    }
-
-    /**
-     * Checks if `value` is a string.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is a string, else `false`.
-     * @example
-     *
-     * _.isString('fred');
-     * // => true
-     */
-    function isString(value) {
-      return typeof value == 'string' ||
-        value && typeof value == 'object' && toString.call(value) == stringClass || false;
-    }
-
-    /**
-     * Checks if `value` is `undefined`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {*} value The value to check.
-     * @returns {boolean} Returns `true` if the `value` is `undefined`, else `false`.
-     * @example
-     *
-     * _.isUndefined(void 0);
-     * // => true
-     */
-    function isUndefined(value) {
-      return typeof value == 'undefined';
-    }
-
-    /**
-     * Creates an object with the same keys as `object` and values generated by
-     * running each own enumerable property of `object` through the callback.
-     * The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, key, object).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new object with values of the results of each `callback` execution.
-     * @example
-     *
-     * _.mapValues({ 'a': 1, 'b': 2, 'c': 3} , function(num) { return num * 3; });
-     * // => { 'a': 3, 'b': 6, 'c': 9 }
-     *
-     * var characters = {
-     *   'fred': { 'name': 'fred', 'age': 40 },
-     *   'pebbles': { 'name': 'pebbles', 'age': 1 }
-     * };
-     *
-     * // using "_.pluck" callback shorthand
-     * _.mapValues(characters, 'age');
-     * // => { 'fred': 40, 'pebbles': 1 }
-     */
-    function mapValues(object, callback, thisArg) {
-      var result = {};
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      forOwn(object, function(value, key, object) {
-        result[key] = callback(value, key, object);
-      });
+     * // => [3]
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': false },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': true }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.dropWhile(users, { 'user': 'barney', 'active': false }), 'user');
+     * // => ['fred', 'pebbles']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.dropWhile(users, 'active', false), 'user');
+     * // => ['pebbles']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.dropWhile(users, 'active'), 'user');
+     * // => ['barney', 'fred', 'pebbles']
+     */
+    function dropWhile(array, predicate, thisArg) {
+      return (array && array.length)
+        ? baseWhile(array, getCallback(predicate, thisArg, 3), true)
+        : [];
+    }
+
+    /**
+     * Fills elements of `array` with `value` from `start` up to, but not
+     * including, `end`.
+     *
+     * **Note:** This method mutates `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to fill.
+     * @param {*} value The value to fill `array` with.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns `array`.
+     * @example
+     *
+     * var array = [1, 2, 3];
+     *
+     * _.fill(array, 'a');
+     * console.log(array);
+     * // => ['a', 'a', 'a']
+     *
+     * _.fill(Array(3), 2);
+     * // => [2, 2, 2]
+     *
+     * _.fill([4, 6, 8], '*', 1, 2);
+     * // => [4, '*', 8]
+     */
+    function fill(array, value, start, end) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (start && typeof start != 'number' && isIterateeCall(array, value, start)) {
+        start = 0;
+        end = length;
+      }
+      return baseFill(array, value, start, end);
+    }
+
+    /**
+     * This method is like `_.find` except that it returns the index of the first
+     * element `predicate` returns truthy for instead of the element itself.
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {number} Returns the index of the found element, else `-1`.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': false },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': true }
+     * ];
+     *
+     * _.findIndex(users, function(chr) {
+     *   return chr.user == 'barney';
+     * });
+     * // => 0
+     *
+     * // using the `_.matches` callback shorthand
+     * _.findIndex(users, { 'user': 'fred', 'active': false });
+     * // => 1
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.findIndex(users, 'active', false);
+     * // => 0
+     *
+     * // using the `_.property` callback shorthand
+     * _.findIndex(users, 'active');
+     * // => 2
+     */
+    var findIndex = createFindIndex();
+
+    /**
+     * This method is like `_.findIndex` except that it iterates over elements
+     * of `collection` from right to left.
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {number} Returns the index of the found element, else `-1`.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': true },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': false }
+     * ];
+     *
+     * _.findLastIndex(users, function(chr) {
+     *   return chr.user == 'pebbles';
+     * });
+     * // => 2
+     *
+     * // using the `_.matches` callback shorthand
+     * _.findLastIndex(users, { 'user': 'barney', 'active': true });
+     * // => 0
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.findLastIndex(users, 'active', false);
+     * // => 2
+     *
+     * // using the `_.property` callback shorthand
+     * _.findLastIndex(users, 'active');
+     * // => 0
+     */
+    var findLastIndex = createFindIndex(true);
+
+    /**
+     * Gets the first element of `array`.
+     *
+     * @static
+     * @memberOf _
+     * @alias head
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {*} Returns the first element of `array`.
+     * @example
+     *
+     * _.first([1, 2, 3]);
+     * // => 1
+     *
+     * _.first([]);
+     * // => undefined
+     */
+    function first(array) {
+      return array ? array[0] : undefined;
+    }
+
+    /**
+     * Flattens a nested array. If `isDeep` is `true` the array is recursively
+     * flattened, otherwise it's only flattened a single level.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to flatten.
+     * @param {boolean} [isDeep] Specify a deep flatten.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the new flattened array.
+     * @example
+     *
+     * _.flatten([1, [2, 3, [4]]]);
+     * // => [1, 2, 3, [4]]
+     *
+     * // using `isDeep`
+     * _.flatten([1, [2, 3, [4]]], true);
+     * // => [1, 2, 3, 4]
+     */
+    function flatten(array, isDeep, guard) {
+      var length = array ? array.length : 0;
+      if (guard && isIterateeCall(array, isDeep, guard)) {
+        isDeep = false;
+      }
+      return length ? baseFlatten(array, isDeep) : [];
+    }
+
+    /**
+     * Recursively flattens a nested array.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to recursively flatten.
+     * @returns {Array} Returns the new flattened array.
+     * @example
+     *
+     * _.flattenDeep([1, [2, 3, [4]]]);
+     * // => [1, 2, 3, 4]
+     */
+    function flattenDeep(array) {
+      var length = array ? array.length : 0;
+      return length ? baseFlatten(array, true) : [];
+    }
+
+    /**
+     * Gets the index at which the first occurrence of `value` is found in `array`
+     * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons. If `fromIndex` is negative, it's used as the offset
+     * from the end of `array`. If `array` is sorted providing `true` for `fromIndex`
+     * performs a faster binary search.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to search.
+     * @param {*} value The value to search for.
+     * @param {boolean|number} [fromIndex=0] The index to search from or `true`
+     *  to perform a binary search on a sorted array.
+     * @returns {number} Returns the index of the matched value, else `-1`.
+     * @example
+     *
+     * _.indexOf([1, 2, 1, 2], 2);
+     * // => 1
+     *
+     * // using `fromIndex`
+     * _.indexOf([1, 2, 1, 2], 2, 2);
+     * // => 3
+     *
+     * // performing a binary search
+     * _.indexOf([1, 1, 2, 2], 2, true);
+     * // => 2
+     */
+    function indexOf(array, value, fromIndex) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return -1;
+      }
+      if (typeof fromIndex == 'number') {
+        fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : fromIndex;
+      } else if (fromIndex) {
+        var index = binaryIndex(array, value);
+        if (index < length &&
+            (value === value ? (value === array[index]) : (array[index] !== array[index]))) {
+          return index;
+        }
+        return -1;
+      }
+      return baseIndexOf(array, value, fromIndex || 0);
+    }
+
+    /**
+     * Gets all but the last element of `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.initial([1, 2, 3]);
+     * // => [1, 2]
+     */
+    function initial(array) {
+      return dropRight(array, 1);
+    }
+
+    /**
+     * Creates an array of unique values that are included in all of the provided
+     * arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @returns {Array} Returns the new array of shared values.
+     * @example
+     * _.intersection([1, 2], [4, 2], [2, 1]);
+     * // => [2]
+     */
+    var intersection = restParam(function(arrays) {
+      var othLength = arrays.length,
+          othIndex = othLength,
+          caches = Array(length),
+          indexOf = getIndexOf(),
+          isCommon = indexOf === baseIndexOf,
+          result = [];
+
+      while (othIndex--) {
+        var value = arrays[othIndex] = isArrayLike(value = arrays[othIndex]) ? value : [];
+        caches[othIndex] = (isCommon && value.length >= 120) ? createCache(othIndex && value) : null;
+      }
+      var array = arrays[0],
+          index = -1,
+          length = array ? array.length : 0,
+          seen = caches[0];
+
+      outer:
+      while (++index < length) {
+        value = array[index];
+        if ((seen ? cacheIndexOf(seen, value) : indexOf(result, value, 0)) < 0) {
+          var othIndex = othLength;
+          while (--othIndex) {
+            var cache = caches[othIndex];
+            if ((cache ? cacheIndexOf(cache, value) : indexOf(arrays[othIndex], value, 0)) < 0) {
+              continue outer;
+            }
+          }
+          if (seen) {
+            seen.push(value);
+          }
+          result.push(value);
+        }
+      }
       return result;
-    }
-
-    /**
-     * Recursively merges own enumerable properties of the source object(s), that
-     * don't resolve to `undefined` into the destination object. Subsequent sources
-     * will overwrite property assignments of previous sources. If a callback is
-     * provided it will be executed to produce the merged values of the destination
-     * and source properties. If the callback returns `undefined` merging will
-     * be handled by the method instead. The callback is bound to `thisArg` and
-     * invoked with two arguments; (objectValue, sourceValue).
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The destination object.
-     * @param {...Object} [source] The source objects.
-     * @param {Function} [callback] The function to customize merging properties.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns the destination object.
-     * @example
-     *
-     * var names = {
-     *   'characters': [
-     *     { 'name': 'barney' },
-     *     { 'name': 'fred' }
-     *   ]
-     * };
-     *
-     * var ages = {
-     *   'characters': [
-     *     { 'age': 36 },
-     *     { 'age': 40 }
-     *   ]
-     * };
-     *
-     * _.merge(names, ages);
-     * // => { 'characters': [{ 'name': 'barney', 'age': 36 }, { 'name': 'fred', 'age': 40 }] }
-     *
-     * var food = {
-     *   'fruits': ['apple'],
-     *   'vegetables': ['beet']
-     * };
-     *
-     * var otherFood = {
-     *   'fruits': ['banana'],
-     *   'vegetables': ['carrot']
-     * };
-     *
-     * _.merge(food, otherFood, function(a, b) {
-     *   return _.isArray(a) ? a.concat(b) : undefined;
-     * });
-     * // => { 'fruits': ['apple', 'banana'], 'vegetables': ['beet', 'carrot] }
-     */
-    function merge(object) {
+    });
+
+    /**
+     * Gets the last element of `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {*} Returns the last element of `array`.
+     * @example
+     *
+     * _.last([1, 2, 3]);
+     * // => 3
+     */
+    function last(array) {
+      var length = array ? array.length : 0;
+      return length ? array[length - 1] : undefined;
+    }
+
+    /**
+     * This method is like `_.indexOf` except that it iterates over elements of
+     * `array` from right to left.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to search.
+     * @param {*} value The value to search for.
+     * @param {boolean|number} [fromIndex=array.length-1] The index to search from
+     *  or `true` to perform a binary search on a sorted array.
+     * @returns {number} Returns the index of the matched value, else `-1`.
+     * @example
+     *
+     * _.lastIndexOf([1, 2, 1, 2], 2);
+     * // => 3
+     *
+     * // using `fromIndex`
+     * _.lastIndexOf([1, 2, 1, 2], 2, 2);
+     * // => 1
+     *
+     * // performing a binary search
+     * _.lastIndexOf([1, 1, 2, 2], 2, true);
+     * // => 3
+     */
+    function lastIndexOf(array, value, fromIndex) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return -1;
+      }
+      var index = length;
+      if (typeof fromIndex == 'number') {
+        index = (fromIndex < 0 ? nativeMax(length + fromIndex, 0) : nativeMin(fromIndex || 0, length - 1)) + 1;
+      } else if (fromIndex) {
+        index = binaryIndex(array, value, true) - 1;
+        var other = array[index];
+        if (value === value ? (value === other) : (other !== other)) {
+          return index;
+        }
+        return -1;
+      }
+      if (value !== value) {
+        return indexOfNaN(array, index, true);
+      }
+      while (index--) {
+        if (array[index] === value) {
+          return index;
+        }
+      }
+      return -1;
+    }
+
+    /**
+     * Removes all provided values from `array` using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * **Note:** Unlike `_.without`, this method mutates `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {...*} [values] The values to remove.
+     * @returns {Array} Returns `array`.
+     * @example
+     *
+     * var array = [1, 2, 3, 1, 2, 3];
+     *
+     * _.pull(array, 2, 3);
+     * console.log(array);
+     * // => [1, 1]
+     */
+    function pull() {
       var args = arguments,
-          length = 2;
-
-      if (!isObject(object)) {
-        return object;
-      }
-      // allows working with `_.reduce` and `_.reduceRight` without using
-      // their `index` and `collection` arguments
-      if (typeof args[2] != 'number') {
-        length = args.length;
-      }
-      if (length > 3 && typeof args[length - 2] == 'function') {
-        var callback = baseCreateCallback(args[--length - 1], args[length--], 2);
-      } else if (length > 2 && typeof args[length - 1] == 'function') {
-        callback = args[--length];
-      }
-      var sources = slice(arguments, 1, length),
-          index = -1,
-          stackA = getArray(),
-          stackB = getArray();
+          array = args[0];
+
+      if (!(array && array.length)) {
+        return array;
+      }
+      var index = 0,
+          indexOf = getIndexOf(),
+          length = args.length;
 
       while (++index < length) {
-        baseMerge(object, sources[index], callback, stackA, stackB);
-      }
-      releaseArray(stackA);
-      releaseArray(stackB);
-      return object;
-    }
-
-    /**
-     * Creates a shallow clone of `object` excluding the specified properties.
-     * Property names may be specified as individual arguments or as arrays of
-     * property names. If a callback is provided it will be executed for each
-     * property of `object` omitting the properties the callback returns truey
-     * for. The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, key, object).
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The source object.
-     * @param {Function|...string|string[]} [callback] The properties to omit or the
-     *  function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns an object without the omitted properties.
-     * @example
-     *
-     * _.omit({ 'name': 'fred', 'age': 40 }, 'age');
-     * // => { 'name': 'fred' }
-     *
-     * _.omit({ 'name': 'fred', 'age': 40 }, function(value) {
-     *   return typeof value == 'number';
+        var fromIndex = 0,
+            value = args[index];
+
+        while ((fromIndex = indexOf(array, value, fromIndex)) > -1) {
+          splice.call(array, fromIndex, 1);
+        }
+      }
+      return array;
+    }
+
+    /**
+     * Removes elements from `array` corresponding to the given indexes and returns
+     * an array of the removed elements. Indexes may be specified as an array of
+     * indexes or as individual arguments.
+     *
+     * **Note:** Unlike `_.at`, this method mutates `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {...(number|number[])} [indexes] The indexes of elements to remove,
+     *  specified as individual indexes or arrays of indexes.
+     * @returns {Array} Returns the new array of removed elements.
+     * @example
+     *
+     * var array = [5, 10, 15, 20];
+     * var evens = _.pullAt(array, 1, 3);
+     *
+     * console.log(array);
+     * // => [5, 15]
+     *
+     * console.log(evens);
+     * // => [10, 20]
+     */
+    var pullAt = restParam(function(array, indexes) {
+      indexes = baseFlatten(indexes);
+
+      var result = baseAt(array, indexes);
+      basePullAt(array, indexes.sort(baseCompareAscending));
+      return result;
+    });
+
+    /**
+     * Removes all elements from `array` that `predicate` returns truthy for
+     * and returns an array of the removed elements. The predicate is bound to
+     * `thisArg` and invoked with three arguments: (value, index, array).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * **Note:** Unlike `_.filter`, this method mutates `array`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to modify.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the new array of removed elements.
+     * @example
+     *
+     * var array = [1, 2, 3, 4];
+     * var evens = _.remove(array, function(n) {
+     *   return n % 2 == 0;
      * });
-     * // => { 'name': 'fred' }
-     */
-    function omit(object, callback, thisArg) {
-      var result = {};
-      if (typeof callback != 'function') {
-        var props = [];
-        forIn(object, function(value, key) {
-          props.push(key);
-        });
-        props = baseDifference(props, baseFlatten(arguments, true, false, 1));
-
-        var index = -1,
-            length = props.length;
-
-        while (++index < length) {
-          var key = props[index];
-          result[key] = object[key];
-        }
-      } else {
-        callback = lodash.createCallback(callback, thisArg, 3);
-        forIn(object, function(value, key, object) {
-          if (!callback(value, key, object)) {
-            result[key] = value;
-          }
-        });
-      }
+     *
+     * console.log(array);
+     * // => [1, 3]
+     *
+     * console.log(evens);
+     * // => [2, 4]
+     */
+    function remove(array, predicate, thisArg) {
+      var result = [];
+      if (!(array && array.length)) {
+        return result;
+      }
+      var index = -1,
+          indexes = [],
+          length = array.length;
+
+      predicate = getCallback(predicate, thisArg, 3);
+      while (++index < length) {
+        var value = array[index];
+        if (predicate(value, index, array)) {
+          result.push(value);
+          indexes.push(index);
+        }
+      }
+      basePullAt(array, indexes);
       return result;
     }
 
     /**
-     * Creates a two dimensional array of an object's key-value pairs,
-     * i.e. `[[key1, value1], [key2, value2]]`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns new array of key-value pairs.
-     * @example
-     *
-     * _.pairs({ 'barney': 36, 'fred': 40 });
-     * // => [['barney', 36], ['fred', 40]] (property order is not guaranteed across environments)
-     */
-    function pairs(object) {
+     * Gets all but the first element of `array`.
+     *
+     * @static
+     * @memberOf _
+     * @alias tail
+     * @category Array
+     * @param {Array} array The array to query.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.rest([1, 2, 3]);
+     * // => [2, 3]
+     */
+    function rest(array) {
+      return drop(array, 1);
+    }
+
+    /**
+     * Creates a slice of `array` from `start` up to, but not including, `end`.
+     *
+     * **Note:** This method is used instead of `Array#slice` to support node
+     * lists in IE < 9 and to ensure dense arrays are returned.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to slice.
+     * @param {number} [start=0] The start position.
+     * @param {number} [end=array.length] The end position.
+     * @returns {Array} Returns the slice of `array`.
+     */
+    function slice(array, start, end) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (end && typeof end != 'number' && isIterateeCall(array, start, end)) {
+        start = 0;
+        end = length;
+      }
+      return baseSlice(array, start, end);
+    }
+
+    /**
+     * Uses a binary search to determine the lowest index at which `value` should
+     * be inserted into `array` in order to maintain its sort order. If an iteratee
+     * function is provided it's invoked for `value` and each element of `array`
+     * to compute their sort ranking. The iteratee is bound to `thisArg` and
+     * invoked with one argument; (value).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
+     * @example
+     *
+     * _.sortedIndex([30, 50], 40);
+     * // => 1
+     *
+     * _.sortedIndex([4, 4, 5, 5], 5);
+     * // => 2
+     *
+     * var dict = { 'data': { 'thirty': 30, 'forty': 40, 'fifty': 50 } };
+     *
+     * // using an iteratee function
+     * _.sortedIndex(['thirty', 'fifty'], 'forty', function(word) {
+     *   return this.data[word];
+     * }, dict);
+     * // => 1
+     *
+     * // using the `_.property` callback shorthand
+     * _.sortedIndex([{ 'x': 30 }, { 'x': 50 }], { 'x': 40 }, 'x');
+     * // => 1
+     */
+    var sortedIndex = createSortedIndex();
+
+    /**
+     * This method is like `_.sortedIndex` except that it returns the highest
+     * index at which `value` should be inserted into `array` in order to
+     * maintain its sort order.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The sorted array to inspect.
+     * @param {*} value The value to evaluate.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {number} Returns the index at which `value` should be inserted
+     *  into `array`.
+     * @example
+     *
+     * _.sortedLastIndex([4, 4, 5, 5], 5);
+     * // => 4
+     */
+    var sortedLastIndex = createSortedIndex(true);
+
+    /**
+     * Creates a slice of `array` with `n` elements taken from the beginning.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to take.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.take([1, 2, 3]);
+     * // => [1]
+     *
+     * _.take([1, 2, 3], 2);
+     * // => [1, 2]
+     *
+     * _.take([1, 2, 3], 5);
+     * // => [1, 2, 3]
+     *
+     * _.take([1, 2, 3], 0);
+     * // => []
+     */
+    function take(array, n, guard) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (guard ? isIterateeCall(array, n, guard) : n == null) {
+        n = 1;
+      }
+      return baseSlice(array, 0, n < 0 ? 0 : n);
+    }
+
+    /**
+     * Creates a slice of `array` with `n` elements taken from the end.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {number} [n=1] The number of elements to take.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.takeRight([1, 2, 3]);
+     * // => [3]
+     *
+     * _.takeRight([1, 2, 3], 2);
+     * // => [2, 3]
+     *
+     * _.takeRight([1, 2, 3], 5);
+     * // => [1, 2, 3]
+     *
+     * _.takeRight([1, 2, 3], 0);
+     * // => []
+     */
+    function takeRight(array, n, guard) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (guard ? isIterateeCall(array, n, guard) : n == null) {
+        n = 1;
+      }
+      n = length - (+n || 0);
+      return baseSlice(array, n < 0 ? 0 : n);
+    }
+
+    /**
+     * Creates a slice of `array` with elements taken from the end. Elements are
+     * taken until `predicate` returns falsey. The predicate is bound to `thisArg`
+     * and invoked with three arguments: (value, index, array).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.takeRightWhile([1, 2, 3], function(n) {
+     *   return n > 1;
+     * });
+     * // => [2, 3]
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': true },
+     *   { 'user': 'fred',    'active': false },
+     *   { 'user': 'pebbles', 'active': false }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.takeRightWhile(users, { 'user': 'pebbles', 'active': false }), 'user');
+     * // => ['pebbles']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.takeRightWhile(users, 'active', false), 'user');
+     * // => ['fred', 'pebbles']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.takeRightWhile(users, 'active'), 'user');
+     * // => []
+     */
+    function takeRightWhile(array, predicate, thisArg) {
+      return (array && array.length)
+        ? baseWhile(array, getCallback(predicate, thisArg, 3), false, true)
+        : [];
+    }
+
+    /**
+     * Creates a slice of `array` with elements taken from the beginning. Elements
+     * are taken until `predicate` returns falsey. The predicate is bound to
+     * `thisArg` and invoked with three arguments: (value, index, array).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to query.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the slice of `array`.
+     * @example
+     *
+     * _.takeWhile([1, 2, 3], function(n) {
+     *   return n < 3;
+     * });
+     * // => [1, 2]
+     *
+     * var users = [
+     *   { 'user': 'barney',  'active': false },
+     *   { 'user': 'fred',    'active': false},
+     *   { 'user': 'pebbles', 'active': true }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.takeWhile(users, { 'user': 'barney', 'active': false }), 'user');
+     * // => ['barney']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.takeWhile(users, 'active', false), 'user');
+     * // => ['barney', 'fred']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.takeWhile(users, 'active'), 'user');
+     * // => []
+     */
+    function takeWhile(array, predicate, thisArg) {
+      return (array && array.length)
+        ? baseWhile(array, getCallback(predicate, thisArg, 3))
+        : [];
+    }
+
+    /**
+     * Creates an array of unique values, in order, from all of the provided arrays
+     * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @returns {Array} Returns the new array of combined values.
+     * @example
+     *
+     * _.union([1, 2], [4, 2], [2, 1]);
+     * // => [1, 2, 4]
+     */
+    var union = restParam(function(arrays) {
+      return baseUniq(baseFlatten(arrays, false, true));
+    });
+
+    /**
+     * Creates a duplicate-free version of an array, using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons, in which only the first occurence of each element
+     * is kept. Providing `true` for `isSorted` performs a faster search algorithm
+     * for sorted arrays. If an iteratee function is provided it's invoked for
+     * each element in the array to generate the criterion by which uniqueness
+     * is computed. The `iteratee` is bound to `thisArg` and invoked with three
+     * arguments: (value, index, array).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @alias unique
+     * @category Array
+     * @param {Array} array The array to inspect.
+     * @param {boolean} [isSorted] Specify the array is sorted.
+     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the new duplicate-value-free array.
+     * @example
+     *
+     * _.uniq([2, 1, 2]);
+     * // => [2, 1]
+     *
+     * // using `isSorted`
+     * _.uniq([1, 1, 2], true);
+     * // => [1, 2]
+     *
+     * // using an iteratee function
+     * _.uniq([1, 2.5, 1.5, 2], function(n) {
+     *   return this.floor(n);
+     * }, Math);
+     * // => [1, 2.5]
+     *
+     * // using the `_.property` callback shorthand
+     * _.uniq([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
+     * // => [{ 'x': 1 }, { 'x': 2 }]
+     */
+    function uniq(array, isSorted, iteratee, thisArg) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      if (isSorted != null && typeof isSorted != 'boolean') {
+        thisArg = iteratee;
+        iteratee = isIterateeCall(array, isSorted, thisArg) ? undefined : isSorted;
+        isSorted = false;
+      }
+      var callback = getCallback();
+      if (!(iteratee == null && callback === baseCallback)) {
+        iteratee = callback(iteratee, thisArg, 3);
+      }
+      return (isSorted && getIndexOf() === baseIndexOf)
+        ? sortedUniq(array, iteratee)
+        : baseUniq(array, iteratee);
+    }
+
+    /**
+     * This method is like `_.zip` except that it accepts an array of grouped
+     * elements and creates an array regrouping the elements to their pre-zip
+     * configuration.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array of grouped elements to process.
+     * @returns {Array} Returns the new array of regrouped elements.
+     * @example
+     *
+     * var zipped = _.zip(['fred', 'barney'], [30, 40], [true, false]);
+     * // => [['fred', 30, true], ['barney', 40, false]]
+     *
+     * _.unzip(zipped);
+     * // => [['fred', 'barney'], [30, 40], [true, false]]
+     */
+    function unzip(array) {
+      if (!(array && array.length)) {
+        return [];
+      }
       var index = -1,
-          props = keys(object),
-          length = props.length,
-          result = Array(length);
-
+          length = 0;
+
+      array = arrayFilter(array, function(group) {
+        if (isArrayLike(group)) {
+          length = nativeMax(group.length, length);
+          return true;
+        }
+      });
+      var result = Array(length);
       while (++index < length) {
-        var key = props[index];
-        result[index] = [key, object[key]];
-      }
-      return result;
-    }
-
-    /**
-     * Creates a shallow clone of `object` composed of the specified properties.
-     * Property names may be specified as individual arguments or as arrays of
-     * property names. If a callback is provided it will be executed for each
-     * property of `object` picking the properties the callback returns truey
-     * for. The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, key, object).
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The source object.
-     * @param {Function|...string|string[]} [callback] The function called per
-     *  iteration or property names to pick, specified as individual property
-     *  names or arrays of property names.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns an object composed of the picked properties.
-     * @example
-     *
-     * _.pick({ 'name': 'fred', '_userid': 'fred1' }, 'name');
-     * // => { 'name': 'fred' }
-     *
-     * _.pick({ 'name': 'fred', '_userid': 'fred1' }, function(value, key) {
-     *   return key.charAt(0) != '_';
-     * });
-     * // => { 'name': 'fred' }
-     */
-    function pick(object, callback, thisArg) {
-      var result = {};
-      if (typeof callback != 'function') {
-        var index = -1,
-            props = baseFlatten(arguments, true, false, 1),
-            length = isObject(object) ? props.length : 0;
-
-        while (++index < length) {
-          var key = props[index];
-          if (key in object) {
-            result[key] = object[key];
-          }
-        }
-      } else {
-        callback = lodash.createCallback(callback, thisArg, 3);
-        forIn(object, function(value, key, object) {
-          if (callback(value, key, object)) {
-            result[key] = value;
-          }
-        });
+        result[index] = arrayMap(array, baseProperty(index));
       }
       return result;
     }
 
     /**
-     * An alternative to `_.reduce` this method transforms `object` to a new
-     * `accumulator` object which is the result of running each of its own
-     * enumerable properties through a callback, with each callback execution
-     * potentially mutating the `accumulator` object. The callback is bound to
-     * `thisArg` and invoked with four arguments; (accumulator, value, key, object).
-     * Callbacks may exit iteration early by explicitly returning `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Array|Object} object The object to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [accumulator] The custom accumulator value.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the accumulated value.
-     * @example
-     *
-     * var squares = _.transform([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], function(result, num) {
-     *   num *= num;
-     *   if (num % 2) {
-     *     return result.push(num) < 3;
-     *   }
-     * });
-     * // => [1, 9, 25]
-     *
-     * var mapped = _.transform({ 'a': 1, 'b': 2, 'c': 3 }, function(result, num, key) {
-     *   result[key] = num * 3;
-     * });
-     * // => { 'a': 3, 'b': 6, 'c': 9 }
-     */
-    function transform(object, callback, accumulator, thisArg) {
-      var isArr = isArray(object);
-      if (accumulator == null) {
-        if (isArr) {
-          accumulator = [];
-        } else {
-          var ctor = object && object.constructor,
-              proto = ctor && ctor.prototype;
-
-          accumulator = baseCreate(proto);
-        }
-      }
-      if (callback) {
-        callback = lodash.createCallback(callback, thisArg, 4);
-        (isArr ? forEach : forOwn)(object, function(value, index, object) {
-          return callback(accumulator, value, index, object);
-        });
-      }
-      return accumulator;
-    }
-
-    /**
-     * Creates an array composed of the own enumerable property values of `object`.
-     *
-     * @static
-     * @memberOf _
-     * @category Objects
-     * @param {Object} object The object to inspect.
-     * @returns {Array} Returns an array of property values.
-     * @example
-     *
-     * _.values({ 'one': 1, 'two': 2, 'three': 3 });
-     * // => [1, 2, 3] (property order is not guaranteed across environments)
-     */
-    function values(object) {
+     * This method is like `_.unzip` except that it accepts an iteratee to specify
+     * how regrouped values should be combined. The `iteratee` is bound to `thisArg`
+     * and invoked with four arguments: (accumulator, value, index, group).
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array of grouped elements to process.
+     * @param {Function} [iteratee] The function to combine regrouped values.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the new array of regrouped elements.
+     * @example
+     *
+     * var zipped = _.zip([1, 2], [10, 20], [100, 200]);
+     * // => [[1, 10, 100], [2, 20, 200]]
+     *
+     * _.unzipWith(zipped, _.add);
+     * // => [3, 30, 300]
+     */
+    function unzipWith(array, iteratee, thisArg) {
+      var length = array ? array.length : 0;
+      if (!length) {
+        return [];
+      }
+      var result = unzip(array);
+      if (iteratee == null) {
+        return result;
+      }
+      iteratee = bindCallback(iteratee, thisArg, 4);
+      return arrayMap(result, function(group) {
+        return arrayReduce(group, iteratee, undefined, true);
+      });
+    }
+
+    /**
+     * Creates an array excluding all provided values using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {Array} array The array to filter.
+     * @param {...*} [values] The values to exclude.
+     * @returns {Array} Returns the new array of filtered values.
+     * @example
+     *
+     * _.without([1, 2, 1, 3], 1, 2);
+     * // => [3]
+     */
+    var without = restParam(function(array, values) {
+      return isArrayLike(array)
+        ? baseDifference(array, values)
+        : [];
+    });
+
+    /**
+     * Creates an array of unique values that is the [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
+     * of the provided arrays.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {...Array} [arrays] The arrays to inspect.
+     * @returns {Array} Returns the new array of values.
+     * @example
+     *
+     * _.xor([1, 2], [4, 2]);
+     * // => [1, 4]
+     */
+    function xor() {
       var index = -1,
-          props = keys(object),
-          length = props.length,
-          result = Array(length);
+          length = arguments.length;
 
       while (++index < length) {
-        result[index] = object[props[index]];
+        var array = arguments[index];
+        if (isArrayLike(array)) {
+          var result = result
+            ? arrayPush(baseDifference(result, array), baseDifference(array, result))
+            : array;
+        }
+      }
+      return result ? baseUniq(result) : [];
+    }
+
+    /**
+     * Creates an array of grouped elements, the first of which contains the first
+     * elements of the given arrays, the second of which contains the second elements
+     * of the given arrays, and so on.
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {...Array} [arrays] The arrays to process.
+     * @returns {Array} Returns the new array of grouped elements.
+     * @example
+     *
+     * _.zip(['fred', 'barney'], [30, 40], [true, false]);
+     * // => [['fred', 30, true], ['barney', 40, false]]
+     */
+    var zip = restParam(unzip);
+
+    /**
+     * The inverse of `_.pairs`; this method returns an object composed from arrays
+     * of property names and values. Provide either a single two dimensional array,
+     * e.g. `[[key1, value1], [key2, value2]]` or two arrays, one of property names
+     * and one of corresponding values.
+     *
+     * @static
+     * @memberOf _
+     * @alias object
+     * @category Array
+     * @param {Array} props The property names.
+     * @param {Array} [values=[]] The property values.
+     * @returns {Object} Returns the new object.
+     * @example
+     *
+     * _.zipObject([['fred', 30], ['barney', 40]]);
+     * // => { 'fred': 30, 'barney': 40 }
+     *
+     * _.zipObject(['fred', 'barney'], [30, 40]);
+     * // => { 'fred': 30, 'barney': 40 }
+     */
+    function zipObject(props, values) {
+      var index = -1,
+          length = props ? props.length : 0,
+          result = {};
+
+      if (length && !values && !isArray(props[0])) {
+        values = [];
+      }
+      while (++index < length) {
+        var key = props[index];
+        if (values) {
+          result[key] = values[index];
+        } else if (key) {
+          result[key[0]] = key[1];
+        }
       }
       return result;
     }
 
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates an array of elements from the specified indexes, or keys, of the
-     * `collection`. Indexes may be specified as individual arguments or as arrays
-     * of indexes.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {...(number|number[]|string|string[])} [index] The indexes of `collection`
-     *   to retrieve, specified as individual indexes or arrays of indexes.
-     * @returns {Array} Returns a new array of elements corresponding to the
-     *  provided indexes.
-     * @example
-     *
-     * _.at(['a', 'b', 'c', 'd', 'e'], [0, 2, 4]);
-     * // => ['a', 'c', 'e']
-     *
-     * _.at(['fred', 'barney', 'pebbles'], 0, 2);
-     * // => ['fred', 'pebbles']
-     */
-    function at(collection) {
-      var args = arguments,
-          index = -1,
-          props = baseFlatten(args, true, false, 1),
-          length = (args[2] && args[2][args[1]] === collection) ? 1 : props.length,
-          result = Array(length);
-
-      while(++index < length) {
-        result[index] = collection[props[index]];
-      }
+    /**
+     * This method is like `_.zip` except that it accepts an iteratee to specify
+     * how grouped values should be combined. The `iteratee` is bound to `thisArg`
+     * and invoked with four arguments: (accumulator, value, index, group).
+     *
+     * @static
+     * @memberOf _
+     * @category Array
+     * @param {...Array} [arrays] The arrays to process.
+     * @param {Function} [iteratee] The function to combine grouped values.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the new array of grouped elements.
+     * @example
+     *
+     * _.zipWith([1, 2], [10, 20], [100, 200], _.add);
+     * // => [111, 222]
+     */
+    var zipWith = restParam(function(arrays) {
+      var length = arrays.length,
+          iteratee = length > 2 ? arrays[length - 2] : undefined,
+          thisArg = length > 1 ? arrays[length - 1] : undefined;
+
+      if (length > 2 && typeof iteratee == 'function') {
+        length -= 2;
+      } else {
+        iteratee = (length > 1 && typeof thisArg == 'function') ? (--length, thisArg) : undefined;
+        thisArg = undefined;
+      }
+      arrays.length = length;
+      return unzipWith(arrays, iteratee, thisArg);
+    });
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a `lodash` object that wraps `value` with explicit method
+     * chaining enabled.
+     *
+     * @static
+     * @memberOf _
+     * @category Chain
+     * @param {*} value The value to wrap.
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney',  'age': 36 },
+     *   { 'user': 'fred',    'age': 40 },
+     *   { 'user': 'pebbles', 'age': 1 }
+     * ];
+     *
+     * var youngest = _.chain(users)
+     *   .sortBy('age')
+     *   .map(function(chr) {
+     *     return chr.user + ' is ' + chr.age;
+     *   })
+     *   .first()
+     *   .value();
+     * // => 'pebbles is 1'
+     */
+    function chain(value) {
+      var result = lodash(value);
+      result.__chain__ = true;
       return result;
     }
 
     /**
-     * Checks if a given value is present in a collection using strict equality
-     * for comparisons, i.e. `===`. If `fromIndex` is negative, it is used as the
-     * offset from the end of the collection.
-     *
-     * @static
-     * @memberOf _
-     * @alias include
-     * @category Collections
+     * This method invokes `interceptor` and returns `value`. The interceptor is
+     * bound to `thisArg` and invoked with one argument; (value). The purpose of
+     * this method is to "tap into" a method chain in order to perform operations
+     * on intermediate results within the chain.
+     *
+     * @static
+     * @memberOf _
+     * @category Chain
+     * @param {*} value The value to provide to `interceptor`.
+     * @param {Function} interceptor The function to invoke.
+     * @param {*} [thisArg] The `this` binding of `interceptor`.
+     * @returns {*} Returns `value`.
+     * @example
+     *
+     * _([1, 2, 3])
+     *  .tap(function(array) {
+     *    array.pop();
+     *  })
+     *  .reverse()
+     *  .value();
+     * // => [2, 1]
+     */
+    function tap(value, interceptor, thisArg) {
+      interceptor.call(thisArg, value);
+      return value;
+    }
+
+    /**
+     * This method is like `_.tap` except that it returns the result of `interceptor`.
+     *
+     * @static
+     * @memberOf _
+     * @category Chain
+     * @param {*} value The value to provide to `interceptor`.
+     * @param {Function} interceptor The function to invoke.
+     * @param {*} [thisArg] The `this` binding of `interceptor`.
+     * @returns {*} Returns the result of `interceptor`.
+     * @example
+     *
+     * _('  abc  ')
+     *  .chain()
+     *  .trim()
+     *  .thru(function(value) {
+     *    return [value];
+     *  })
+     *  .value();
+     * // => ['abc']
+     */
+    function thru(value, interceptor, thisArg) {
+      return interceptor.call(thisArg, value);
+    }
+
+    /**
+     * Enables explicit method chaining on the wrapper object.
+     *
+     * @name chain
+     * @memberOf _
+     * @category Chain
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 40 }
+     * ];
+     *
+     * // without explicit chaining
+     * _(users).first();
+     * // => { 'user': 'barney', 'age': 36 }
+     *
+     * // with explicit chaining
+     * _(users).chain()
+     *   .first()
+     *   .pick('user')
+     *   .value();
+     * // => { 'user': 'barney' }
+     */
+    function wrapperChain() {
+      return chain(this);
+    }
+
+    /**
+     * Executes the chained sequence and returns the wrapped result.
+     *
+     * @name commit
+     * @memberOf _
+     * @category Chain
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var array = [1, 2];
+     * var wrapped = _(array).push(3);
+     *
+     * console.log(array);
+     * // => [1, 2]
+     *
+     * wrapped = wrapped.commit();
+     * console.log(array);
+     * // => [1, 2, 3]
+     *
+     * wrapped.last();
+     * // => 3
+     *
+     * console.log(array);
+     * // => [1, 2, 3]
+     */
+    function wrapperCommit() {
+      return new LodashWrapper(this.value(), this.__chain__);
+    }
+
+    /**
+     * Creates a new array joining a wrapped array with any additional arrays
+     * and/or values.
+     *
+     * @name concat
+     * @memberOf _
+     * @category Chain
+     * @param {...*} [values] The values to concatenate.
+     * @returns {Array} Returns the new concatenated array.
+     * @example
+     *
+     * var array = [1];
+     * var wrapped = _(array).concat(2, [3], [[4]]);
+     *
+     * console.log(wrapped.value());
+     * // => [1, 2, 3, [4]]
+     *
+     * console.log(array);
+     * // => [1]
+     */
+    var wrapperConcat = restParam(function(values) {
+      values = baseFlatten(values);
+      return this.thru(function(array) {
+        return arrayConcat(isArray(array) ? array : [toObject(array)], values);
+      });
+    });
+
+    /**
+     * Creates a clone of the chained sequence planting `value` as the wrapped value.
+     *
+     * @name plant
+     * @memberOf _
+     * @category Chain
+     * @returns {Object} Returns the new `lodash` wrapper instance.
+     * @example
+     *
+     * var array = [1, 2];
+     * var wrapped = _(array).map(function(value) {
+     *   return Math.pow(value, 2);
+     * });
+     *
+     * var other = [3, 4];
+     * var otherWrapped = wrapped.plant(other);
+     *
+     * otherWrapped.value();
+     * // => [9, 16]
+     *
+     * wrapped.value();
+     * // => [1, 4]
+     */
+    function wrapperPlant(value) {
+      var result,
+          parent = this;
+
+      while (parent instanceof baseLodash) {
+        var clone = wrapperClone(parent);
+        if (result) {
+          previous.__wrapped__ = clone;
+        } else {
+          result = clone;
+        }
+        var previous = clone;
+        parent = parent.__wrapped__;
+      }
+      previous.__wrapped__ = value;
+      return result;
+    }
+
+    /**
+     * Reverses the wrapped array so the first element becomes the last, the
+     * second element becomes the second to last, and so on.
+     *
+     * **Note:** This method mutates the wrapped array.
+     *
+     * @name reverse
+     * @memberOf _
+     * @category Chain
+     * @returns {Object} Returns the new reversed `lodash` wrapper instance.
+     * @example
+     *
+     * var array = [1, 2, 3];
+     *
+     * _(array).reverse().value()
+     * // => [3, 2, 1]
+     *
+     * console.log(array);
+     * // => [3, 2, 1]
+     */
+    function wrapperReverse() {
+      var value = this.__wrapped__;
+
+      var interceptor = function(value) {
+        return value.reverse();
+      };
+      if (value instanceof LazyWrapper) {
+        var wrapped = value;
+        if (this.__actions__.length) {
+          wrapped = new LazyWrapper(this);
+        }
+        wrapped = wrapped.reverse();
+        wrapped.__actions__.push({ 'func': thru, 'args': [interceptor], 'thisArg': undefined });
+        return new LodashWrapper(wrapped, this.__chain__);
+      }
+      return this.thru(interceptor);
+    }
+
+    /**
+     * Produces the result of coercing the unwrapped value to a string.
+     *
+     * @name toString
+     * @memberOf _
+     * @category Chain
+     * @returns {string} Returns the coerced string value.
+     * @example
+     *
+     * _([1, 2, 3]).toString();
+     * // => '1,2,3'
+     */
+    function wrapperToString() {
+      return (this.value() + '');
+    }
+
+    /**
+     * Executes the chained sequence to extract the unwrapped value.
+     *
+     * @name value
+     * @memberOf _
+     * @alias run, toJSON, valueOf
+     * @category Chain
+     * @returns {*} Returns the resolved unwrapped value.
+     * @example
+     *
+     * _([1, 2, 3]).value();
+     * // => [1, 2, 3]
+     */
+    function wrapperValue() {
+      return baseWrapperValue(this.__wrapped__, this.__actions__);
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates an array of elements corresponding to the given keys, or indexes,
+     * of `collection`. Keys may be specified as individual arguments or as arrays
+     * of keys.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {*} target The value to check for.
-     * @param {number} [fromIndex=0] The index to search from.
-     * @returns {boolean} Returns `true` if the `target` element is found, else `false`.
-     * @example
-     *
-     * _.contains([1, 2, 3], 1);
-     * // => true
-     *
-     * _.contains([1, 2, 3], 1, 2);
-     * // => false
-     *
-     * _.contains({ 'name': 'fred', 'age': 40 }, 'fred');
-     * // => true
-     *
-     * _.contains('pebbles', 'eb');
-     * // => true
-     */
-    function contains(collection, target, fromIndex) {
-      var index = -1,
-          indexOf = getIndexOf(),
-          length = collection ? collection.length : 0,
-          result = false;
-
-      fromIndex = (fromIndex < 0 ? nativeMax(0, length + fromIndex) : fromIndex) || 0;
-      if (isArray(collection)) {
-        result = indexOf(collection, target, fromIndex) > -1;
-      } else if (typeof length == 'number') {
-        result = (isString(collection) ? collection.indexOf(target, fromIndex) : indexOf(collection, target, fromIndex)) > -1;
-      } else {
-        forOwn(collection, function(value) {
-          if (++index >= fromIndex) {
-            return !(result = value === target);
-          }
-        });
-      }
-      return result;
-    }
+     * @param {...(number|number[]|string|string[])} [props] The property names
+     *  or indexes of elements to pick, specified individually or in arrays.
+     * @returns {Array} Returns the new array of picked elements.
+     * @example
+     *
+     * _.at(['a', 'b', 'c'], [0, 2]);
+     * // => ['a', 'c']
+     *
+     * _.at(['barney', 'fred', 'pebbles'], 0, 2);
+     * // => ['barney', 'pebbles']
+     */
+    var at = restParam(function(collection, props) {
+      return baseAt(collection, baseFlatten(props));
+    });
 
     /**
      * Creates an object composed of keys generated from the results of running
-     * each element of `collection` through the callback. The corresponding value
-     * of each key is the number of times the key was returned by the callback.
-     * The callback is bound to `thisArg` and invoked with three arguments;
+     * each element of `collection` through `iteratee`. The corresponding value
+     * of each key is the number of times the key was returned by `iteratee`.
+     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
      * (value, index|key, collection).
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {Object} Returns the composed aggregate object.
      * @example
      *
-     * _.countBy([4.3, 6.1, 6.4], function(num) { return Math.floor(num); });
+     * _.countBy([4.3, 6.1, 6.4], function(n) {
+     *   return Math.floor(n);
+     * });
      * // => { '4': 1, '6': 2 }
      *
-     * _.countBy([4.3, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
+     * _.countBy([4.3, 6.1, 6.4], function(n) {
+     *   return this.floor(n);
+     * }, Math);
      * // => { '4': 1, '6': 2 }
      *
      * _.countBy(['one', 'two', 'three'], 'length');
      * // => { '3': 2, '5': 1 }
      */
     var countBy = createAggregator(function(result, value, key) {
-      (hasOwnProperty.call(result, key) ? result[key]++ : result[key] = 1);
+      hasOwnProperty.call(result, key) ? ++result[key] : (result[key] = 1);
     });
 
     /**
-     * Checks if the given callback returns truey value for **all** elements of
-     * a collection. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+     * Checks if `predicate` returns truthy for **all** elements of `collection`.
+     * The predicate is bound to `thisArg` and invoked with three arguments:
+     * (value, index|key, collection).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
      *
      * @static
      * @memberOf _
      * @alias all
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {boolean} Returns `true` if all elements passed the callback check,
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {boolean} Returns `true` if all elements pass the predicate check,
      *  else `false`.
      * @example
      *
-     * _.every([true, 1, null, 'yes']);
+     * _.every([true, 1, null, 'yes'], Boolean);
      * // => false
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * var users = [
+     *   { 'user': 'barney', 'active': false },
+     *   { 'user': 'fred',   'active': false }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.every(characters, 'age');
+     * // using the `_.matches` callback shorthand
+     * _.every(users, { 'user': 'barney', 'active': false });
+     * // => false
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.every(users, 'active', false);
      * // => true
      *
-     * // using "_.where" callback shorthand
-     * _.every(characters, { 'age': 36 });
+     * // using the `_.property` callback shorthand
+     * _.every(users, 'active');
      * // => false
      */
-    function every(collection, callback, thisArg) {
-      var result = true;
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      if (typeof length == 'number') {
-        while (++index < length) {
-          if (!(result = !!callback(collection[index], index, collection))) {
-            break;
-          }
-        }
-      } else {
-        forOwn(collection, function(value, index, collection) {
-          return (result = !!callback(value, index, collection));
-        });
-      }
-      return result;
-    }
-
-    /**
-     * Iterates over elements of a collection, returning an array of all elements
-     * the callback returns truey for. The callback is bound to `thisArg` and
-     * invoked with three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+    function every(collection, predicate, thisArg) {
+      var func = isArray(collection) ? arrayEvery : baseEvery;
+      if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
+        predicate = undefined;
+      }
+      if (typeof predicate != 'function' || thisArg !== undefined) {
+        predicate = getCallback(predicate, thisArg, 3);
+      }
+      return func(collection, predicate);
+    }
+
+    /**
+     * Iterates over elements of `collection`, returning an array of all elements
+     * `predicate` returns truthy for. The predicate is bound to `thisArg` and
+     * invoked with three arguments: (value, index|key, collection).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
      *
      * @static
      * @memberOf _
      * @alias select
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of elements that passed the callback check.
-     * @example
-     *
-     * var evens = _.filter([1, 2, 3, 4, 5, 6], function(num) { return num % 2 == 0; });
-     * // => [2, 4, 6]
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'blocked': false },
-     *   { 'name': 'fred',   'age': 40, 'blocked': true }
-     * ];
-     *
-     * // using "_.pluck" callback shorthand
-     * _.filter(characters, 'blocked');
-     * // => [{ 'name': 'fred', 'age': 40, 'blocked': true }]
-     *
-     * // using "_.where" callback shorthand
-     * _.filter(characters, { 'age': 36 });
-     * // => [{ 'name': 'barney', 'age': 36, 'blocked': false }]
-     */
-    function filter(collection, callback, thisArg) {
-      var result = [];
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      if (typeof length == 'number') {
-        while (++index < length) {
-          var value = collection[index];
-          if (callback(value, index, collection)) {
-            result.push(value);
-          }
-        }
-      } else {
-        forOwn(collection, function(value, index, collection) {
-          if (callback(value, index, collection)) {
-            result.push(value);
-          }
-        });
-      }
-      return result;
-    }
-
-    /**
-     * Iterates over elements of a collection, returning the first element that
-     * the callback returns truey for. The callback is bound to `thisArg` and
-     * invoked with three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @alias detect, findWhere
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the found element, else `undefined`.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36, 'blocked': false },
-     *   { 'name': 'fred',    'age': 40, 'blocked': true },
-     *   { 'name': 'pebbles', 'age': 1,  'blocked': false }
-     * ];
-     *
-     * _.find(characters, function(chr) {
-     *   return chr.age < 40;
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the new filtered array.
+     * @example
+     *
+     * _.filter([4, 5, 6], function(n) {
+     *   return n % 2 == 0;
      * });
-     * // => { 'name': 'barney', 'age': 36, 'blocked': false }
-     *
-     * // using "_.where" callback shorthand
-     * _.find(characters, { 'age': 1 });
-     * // =>  { 'name': 'pebbles', 'age': 1, 'blocked': false }
-     *
-     * // using "_.pluck" callback shorthand
-     * _.find(characters, 'blocked');
-     * // => { 'name': 'fred', 'age': 40, 'blocked': true }
-     */
-    function find(collection, callback, thisArg) {
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      if (typeof length == 'number') {
-        while (++index < length) {
-          var value = collection[index];
-          if (callback(value, index, collection)) {
-            return value;
-          }
-        }
-      } else {
-        var result;
-        forOwn(collection, function(value, index, collection) {
-          if (callback(value, index, collection)) {
-            result = value;
-            return false;
-          }
-        });
-        return result;
-      }
-    }
-
-    /**
-     * This method is like `_.find` except that it iterates over elements
-     * of a `collection` from right to left.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the found element, else `undefined`.
-     * @example
-     *
-     * _.findLast([1, 2, 3, 4], function(num) {
-     *   return num % 2 == 1;
+     * // => [4, 6]
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': true },
+     *   { 'user': 'fred',   'age': 40, 'active': false }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.filter(users, { 'age': 36, 'active': true }), 'user');
+     * // => ['barney']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.filter(users, 'active', false), 'user');
+     * // => ['fred']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.filter(users, 'active'), 'user');
+     * // => ['barney']
+     */
+    function filter(collection, predicate, thisArg) {
+      var func = isArray(collection) ? arrayFilter : baseFilter;
+      predicate = getCallback(predicate, thisArg, 3);
+      return func(collection, predicate);
+    }
+
+    /**
+     * Iterates over elements of `collection`, returning the first element
+     * `predicate` returns truthy for. The predicate is bound to `thisArg` and
+     * invoked with three arguments: (value, index|key, collection).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @alias detect
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {*} Returns the matched element, else `undefined`.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney',  'age': 36, 'active': true },
+     *   { 'user': 'fred',    'age': 40, 'active': false },
+     *   { 'user': 'pebbles', 'age': 1,  'active': true }
+     * ];
+     *
+     * _.result(_.find(users, function(chr) {
+     *   return chr.age < 40;
+     * }), 'user');
+     * // => 'barney'
+     *
+     * // using the `_.matches` callback shorthand
+     * _.result(_.find(users, { 'age': 1, 'active': true }), 'user');
+     * // => 'pebbles'
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.result(_.find(users, 'active', false), 'user');
+     * // => 'fred'
+     *
+     * // using the `_.property` callback shorthand
+     * _.result(_.find(users, 'active'), 'user');
+     * // => 'barney'
+     */
+    var find = createFind(baseEach);
+
+    /**
+     * This method is like `_.find` except that it iterates over elements of
+     * `collection` from right to left.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {*} Returns the matched element, else `undefined`.
+     * @example
+     *
+     * _.findLast([1, 2, 3, 4], function(n) {
+     *   return n % 2 == 1;
      * });
      * // => 3
      */
-    function findLast(collection, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      forEachRight(collection, function(value, index, collection) {
-        if (callback(value, index, collection)) {
-          result = value;
-          return false;
-        }
-      });
-      return result;
-    }
-
-    /**
-     * Iterates over elements of a collection, executing the callback for each
-     * element. The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, index|key, collection). Callbacks may exit iteration early by
-     * explicitly returning `false`.
-     *
-     * Note: As with other "Collections" methods, objects with a `length` property
+    var findLast = createFind(baseEachRight, true);
+
+    /**
+     * Performs a deep comparison between each element in `collection` and the
+     * source object, returning the first element that has equivalent property
+     * values.
+     *
+     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
+     * numbers, `Object` objects, regexes, and strings. Objects are compared by
+     * their own, not inherited, enumerable properties. For comparing a single
+     * own or inherited property value see `_.matchesProperty`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {Object} source The object of property values to match.
+     * @returns {*} Returns the matched element, else `undefined`.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': true },
+     *   { 'user': 'fred',   'age': 40, 'active': false }
+     * ];
+     *
+     * _.result(_.findWhere(users, { 'age': 36, 'active': true }), 'user');
+     * // => 'barney'
+     *
+     * _.result(_.findWhere(users, { 'age': 40, 'active': false }), 'user');
+     * // => 'fred'
+     */
+    function findWhere(collection, source) {
+      return find(collection, baseMatches(source));
+    }
+
+    /**
+     * Iterates over elements of `collection` invoking `iteratee` for each element.
+     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
+     * (value, index|key, collection). Iteratee functions may exit iteration early
+     * by explicitly returning `false`.
+     *
+     * **Note:** As with other "Collections" methods, objects with a "length" property
      * are iterated like arrays. To avoid this behavior `_.forIn` or `_.forOwn`
      * may be used for object iteration.
      *
      * @static
      * @memberOf _
      * @alias each
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {Array|Object|string} Returns `collection`.
      * @example
      *
-     * _([1, 2, 3]).forEach(function(num) { console.log(num); }).join(',');
-     * // => logs each number and returns '1,2,3'
-     *
-     * _.forEach({ 'one': 1, 'two': 2, 'three': 3 }, function(num) { console.log(num); });
-     * // => logs each number and returns the object (property order is not guaranteed across environments)
-     */
-    function forEach(collection, callback, thisArg) {
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      callback = callback && typeof thisArg == 'undefined' ? callback : baseCreateCallback(callback, thisArg, 3);
-      if (typeof length == 'number') {
-        while (++index < length) {
-          if (callback(collection[index], index, collection) === false) {
-            break;
-          }
-        }
-      } else {
-        forOwn(collection, callback);
-      }
-      return collection;
-    }
-
-    /**
-     * This method is like `_.forEach` except that it iterates over elements
-     * of a `collection` from right to left.
+     * _([1, 2]).forEach(function(n) {
+     *   console.log(n);
+     * }).value();
+     * // => logs each value from left to right and returns the array
+     *
+     * _.forEach({ 'a': 1, 'b': 2 }, function(n, key) {
+     *   console.log(n, key);
+     * });
+     * // => logs each value-key pair and returns the object (iteration order is not guaranteed)
+     */
+    var forEach = createForEach(arrayEach, baseEach);
+
+    /**
+     * This method is like `_.forEach` except that it iterates over elements of
+     * `collection` from right to left.
      *
      * @static
      * @memberOf _
      * @alias eachRight
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {Array|Object|string} Returns `collection`.
      * @example
      *
-     * _([1, 2, 3]).forEachRight(function(num) { console.log(num); }).join(',');
-     * // => logs each number from right to left and returns '3,2,1'
-     */
-    function forEachRight(collection, callback, thisArg) {
-      var length = collection ? collection.length : 0;
-      callback = callback && typeof thisArg == 'undefined' ? callback : baseCreateCallback(callback, thisArg, 3);
-      if (typeof length == 'number') {
-        while (length--) {
-          if (callback(collection[length], length, collection) === false) {
-            break;
-          }
-        }
+     * _([1, 2]).forEachRight(function(n) {
+     *   console.log(n);
+     * }).value();
+     * // => logs each value from right to left and returns the array
+     */
+    var forEachRight = createForEach(arrayEachRight, baseEachRight);
+
+    /**
+     * Creates an object composed of keys generated from the results of running
+     * each element of `collection` through `iteratee`. The corresponding value
+     * of each key is an array of the elements responsible for generating the key.
+     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
+     * (value, index|key, collection).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns the composed aggregate object.
+     * @example
+     *
+     * _.groupBy([4.2, 6.1, 6.4], function(n) {
+     *   return Math.floor(n);
+     * });
+     * // => { '4': [4.2], '6': [6.1, 6.4] }
+     *
+     * _.groupBy([4.2, 6.1, 6.4], function(n) {
+     *   return this.floor(n);
+     * }, Math);
+     * // => { '4': [4.2], '6': [6.1, 6.4] }
+     *
+     * // using the `_.property` callback shorthand
+     * _.groupBy(['one', 'two', 'three'], 'length');
+     * // => { '3': ['one', 'two'], '5': ['three'] }
+     */
+    var groupBy = createAggregator(function(result, value, key) {
+      if (hasOwnProperty.call(result, key)) {
+        result[key].push(value);
       } else {
-        var props = keys(collection);
-        length = props.length;
-        forOwn(collection, function(value, key, collection) {
-          key = props ? props[--length] : --length;
-          return callback(collection[key], key, collection);
-        });
-      }
-      return collection;
+        result[key] = [value];
+      }
+    });
+
+    /**
+     * Checks if `target` is in `collection` using
+     * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+     * for equality comparisons. If `fromIndex` is negative, it's used as the offset
+     * from the end of `collection`.
+     *
+     * @static
+     * @memberOf _
+     * @alias contains, include
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {*} target The value to search for.
+     * @param {number} [fromIndex=0] The index to search from.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
+     * @returns {boolean} Returns `true` if a matching element is found, else `false`.
+     * @example
+     *
+     * _.includes([1, 2, 3], 1);
+     * // => true
+     *
+     * _.includes([1, 2, 3], 1, 2);
+     * // => false
+     *
+     * _.includes({ 'user': 'fred', 'age': 40 }, 'fred');
+     * // => true
+     *
+     * _.includes('pebbles', 'eb');
+     * // => true
+     */
+    function includes(collection, target, fromIndex, guard) {
+      var length = collection ? getLength(collection) : 0;
+      if (!isLength(length)) {
+        collection = values(collection);
+        length = collection.length;
+      }
+      if (typeof fromIndex != 'number' || (guard && isIterateeCall(target, fromIndex, guard))) {
+        fromIndex = 0;
+      } else {
+        fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : (fromIndex || 0);
+      }
+      return (typeof collection == 'string' || !isArray(collection) && isString(collection))
+        ? (fromIndex <= length && collection.indexOf(target, fromIndex) > -1)
+        : (!!length && getIndexOf(collection, target, fromIndex) > -1);
     }
 
     /**
      * Creates an object composed of keys generated from the results of running
-     * each element of a collection through the callback. The corresponding value
-     * of each key is an array of the elements responsible for generating the key.
-     * The callback is bound to `thisArg` and invoked with three arguments;
+     * each element of `collection` through `iteratee`. The corresponding value
+     * of each key is the last element responsible for generating the key. The
+     * iteratee function is bound to `thisArg` and invoked with three arguments:
      * (value, index|key, collection).
      *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {Object} Returns the composed aggregate object.
      * @example
      *
-     * _.groupBy([4.2, 6.1, 6.4], function(num) { return Math.floor(num); });
-     * // => { '4': [4.2], '6': [6.1, 6.4] }
-     *
-     * _.groupBy([4.2, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
-     * // => { '4': [4.2], '6': [6.1, 6.4] }
-     *
-     * // using "_.pluck" callback shorthand
-     * _.groupBy(['one', 'two', 'three'], 'length');
-     * // => { '3': ['one', 'two'], '5': ['three'] }
-     */
-    var groupBy = createAggregator(function(result, value, key) {
-      (hasOwnProperty.call(result, key) ? result[key] : result[key] = []).push(value);
-    });
-
-    /**
-     * Creates an object composed of keys generated from the results of running
-     * each element of the collection through the given callback. The corresponding
-     * value of each key is the last element responsible for generating the key.
-     * The callback is bound to `thisArg` and invoked with three arguments;
-     * (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Object} Returns the composed aggregate object.
-     * @example
-     *
-     * var keys = [
+     * var keyData = [
      *   { 'dir': 'left', 'code': 97 },
      *   { 'dir': 'right', 'code': 100 }
      * ];
      *
-     * _.indexBy(keys, 'dir');
+     * _.indexBy(keyData, 'dir');
      * // => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }
      *
-     * _.indexBy(keys, function(key) { return String.fromCharCode(key.code); });
+     * _.indexBy(keyData, function(object) {
+     *   return String.fromCharCode(object.code);
+     * });
      * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
      *
-     * _.indexBy(characters, function(key) { this.fromCharCode(key.code); }, String);
+     * _.indexBy(keyData, function(object) {
+     *   return this.fromCharCode(object.code);
+     * }, String);
      * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
      */
     var indexBy = createAggregator(function(result, value, key) {
@@ -3425,19 +6615,19 @@
     });
 
     /**
-     * Invokes the method named by `methodName` on each element in the `collection`
-     * returning an array of the results of each invoked method. Additional arguments
-     * will be provided to each invoked method. If `methodName` is a function it
-     * will be invoked for, and `this` bound to, each element in the `collection`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * Invokes the method at `path` of each element in `collection`, returning
+     * an array of the results of each invoked method. Any additional arguments
+     * are provided to each invoked method. If `methodName` is a function it's
+     * invoked for, and `this` bound to, each element in `collection`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|string} methodName The name of the method to invoke or
+     * @param {Array|Function|string} path The path of the method to invoke or
      *  the function invoked per iteration.
-     * @param {...*} [arg] Arguments to invoke the method with.
-     * @returns {Array} Returns a new array of the results of each invoked method.
+     * @param {...*} [args] The arguments to invoke the method with.
+     * @returns {Array} Returns the array of results.
      * @example
      *
      * _.invoke([[5, 1, 7], [3, 2, 1]], 'sort');
@@ -3446,390 +6636,288 @@
      * _.invoke([123, 456], String.prototype.split, '');
      * // => [['1', '2', '3'], ['4', '5', '6']]
      */
-    function invoke(collection, methodName) {
-      var args = slice(arguments, 2),
-          index = -1,
-          isFunc = typeof methodName == 'function',
-          length = collection ? collection.length : 0,
-          result = Array(typeof length == 'number' ? length : 0);
-
-      forEach(collection, function(value) {
-        result[++index] = (isFunc ? methodName : value[methodName]).apply(value, args);
+    var invoke = restParam(function(collection, path, args) {
+      var index = -1,
+          isFunc = typeof path == 'function',
+          isProp = isKey(path),
+          result = isArrayLike(collection) ? Array(collection.length) : [];
+
+      baseEach(collection, function(value) {
+        var func = isFunc ? path : ((isProp && value != null) ? value[path] : undefined);
+        result[++index] = func ? func.apply(value, args) : invokePath(value, path, args);
       });
       return result;
-    }
-
-    /**
-     * Creates an array of values by running each element in the collection
-     * through the callback. The callback is bound to `thisArg` and invoked with
-     * three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+    });
+
+    /**
+     * Creates an array of values by running each element in `collection` through
+     * `iteratee`. The `iteratee` is bound to `thisArg` and invoked with three
+     * arguments: (value, index|key, collection).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * Many lodash methods are guarded to work as iteratees for methods like
+     * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
+     *
+     * The guarded methods are:
+     * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`,
+     * `drop`, `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`,
+     * `parseInt`, `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`,
+     * `trimLeft`, `trimRight`, `trunc`, `random`, `range`, `sample`, `some`,
+     * `sum`, `uniq`, and `words`
      *
      * @static
      * @memberOf _
      * @alias collect
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of the results of each `callback` execution.
-     * @example
-     *
-     * _.map([1, 2, 3], function(num) { return num * 3; });
-     * // => [3, 6, 9]
-     *
-     * _.map({ 'one': 1, 'two': 2, 'three': 3 }, function(num) { return num * 3; });
-     * // => [3, 6, 9] (property order is not guaranteed across environments)
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
-     *
-     * // using "_.pluck" callback shorthand
-     * _.map(characters, 'name');
-     * // => ['barney', 'fred']
-     */
-    function map(collection, callback, thisArg) {
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      callback = lodash.createCallback(callback, thisArg, 3);
-      if (typeof length == 'number') {
-        var result = Array(length);
-        while (++index < length) {
-          result[index] = callback(collection[index], index, collection);
-        }
-      } else {
-        result = [];
-        forOwn(collection, function(value, key, collection) {
-          result[++index] = callback(value, key, collection);
-        });
-      }
-      return result;
-    }
-
-    /**
-     * Retrieves the maximum value of a collection. If the collection is empty or
-     * falsey `-Infinity` is returned. If a callback is provided it will be executed
-     * for each value in the collection to generate the criterion by which the value
-     * is ranked. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the maximum value.
-     * @example
-     *
-     * _.max([4, 2, 8, 6]);
-     * // => 8
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the new mapped array.
+     * @example
+     *
+     * function timesThree(n) {
+     *   return n * 3;
+     * }
+     *
+     * _.map([1, 2], timesThree);
+     * // => [3, 6]
+     *
+     * _.map({ 'a': 1, 'b': 2 }, timesThree);
+     * // => [3, 6] (iteration order is not guaranteed)
+     *
+     * var users = [
+     *   { 'user': 'barney' },
+     *   { 'user': 'fred' }
      * ];
      *
-     * _.max(characters, function(chr) { return chr.age; });
-     * // => { 'name': 'fred', 'age': 40 };
-     *
-     * // using "_.pluck" callback shorthand
-     * _.max(characters, 'age');
-     * // => { 'name': 'fred', 'age': 40 };
-     */
-    function max(collection, callback, thisArg) {
-      var computed = -Infinity,
-          result = computed;
-
-      // allows working with functions like `_.map` without using
-      // their `index` argument as a callback
-      if (typeof callback != 'function' && thisArg && thisArg[callback] === collection) {
-        callback = null;
-      }
-      if (callback == null && isArray(collection)) {
-        var index = -1,
-            length = collection.length;
-
-        while (++index < length) {
-          var value = collection[index];
-          if (value > result) {
-            result = value;
-          }
-        }
-      } else {
-        callback = (callback == null && isString(collection))
-          ? charAtCallback
-          : lodash.createCallback(callback, thisArg, 3);
-
-        forEach(collection, function(value, index, collection) {
-          var current = callback(value, index, collection);
-          if (current > computed) {
-            computed = current;
-            result = value;
-          }
-        });
-      }
-      return result;
-    }
-
-    /**
-     * Retrieves the minimum value of a collection. If the collection is empty or
-     * falsey `Infinity` is returned. If a callback is provided it will be executed
-     * for each value in the collection to generate the criterion by which the value
-     * is ranked. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * // using the `_.property` callback shorthand
+     * _.map(users, 'user');
+     * // => ['barney', 'fred']
+     */
+    function map(collection, iteratee, thisArg) {
+      var func = isArray(collection) ? arrayMap : baseMap;
+      iteratee = getCallback(iteratee, thisArg, 3);
+      return func(collection, iteratee);
+    }
+
+    /**
+     * Creates an array of elements split into two groups, the first of which
+     * contains elements `predicate` returns truthy for, while the second of which
+     * contains elements `predicate` returns falsey for. The predicate is bound
+     * to `thisArg` and invoked with three arguments: (value, index|key, collection).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the minimum value.
-     * @example
-     *
-     * _.min([4, 2, 8, 6]);
-     * // => 2
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the array of grouped elements.
+     * @example
+     *
+     * _.partition([1, 2, 3], function(n) {
+     *   return n % 2;
+     * });
+     * // => [[1, 3], [2]]
+     *
+     * _.partition([1.2, 2.3, 3.4], function(n) {
+     *   return this.floor(n) % 2;
+     * }, Math);
+     * // => [[1.2, 3.4], [2.3]]
+     *
+     * var users = [
+     *   { 'user': 'barney',  'age': 36, 'active': false },
+     *   { 'user': 'fred',    'age': 40, 'active': true },
+     *   { 'user': 'pebbles', 'age': 1,  'active': false }
      * ];
      *
-     * _.min(characters, function(chr) { return chr.age; });
-     * // => { 'name': 'barney', 'age': 36 };
-     *
-     * // using "_.pluck" callback shorthand
-     * _.min(characters, 'age');
-     * // => { 'name': 'barney', 'age': 36 };
-     */
-    function min(collection, callback, thisArg) {
-      var computed = Infinity,
-          result = computed;
-
-      // allows working with functions like `_.map` without using
-      // their `index` argument as a callback
-      if (typeof callback != 'function' && thisArg && thisArg[callback] === collection) {
-        callback = null;
-      }
-      if (callback == null && isArray(collection)) {
-        var index = -1,
-            length = collection.length;
-
-        while (++index < length) {
-          var value = collection[index];
-          if (value < result) {
-            result = value;
-          }
-        }
-      } else {
-        callback = (callback == null && isString(collection))
-          ? charAtCallback
-          : lodash.createCallback(callback, thisArg, 3);
-
-        forEach(collection, function(value, index, collection) {
-          var current = callback(value, index, collection);
-          if (current < computed) {
-            computed = current;
-            result = value;
-          }
-        });
-      }
-      return result;
-    }
-
-    /**
-     * Retrieves the value of a specified property from all elements in the collection.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Collections
+     * var mapper = function(array) {
+     *   return _.pluck(array, 'user');
+     * };
+     *
+     * // using the `_.matches` callback shorthand
+     * _.map(_.partition(users, { 'age': 1, 'active': false }), mapper);
+     * // => [['pebbles'], ['barney', 'fred']]
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.map(_.partition(users, 'active', false), mapper);
+     * // => [['barney', 'pebbles'], ['fred']]
+     *
+     * // using the `_.property` callback shorthand
+     * _.map(_.partition(users, 'active'), mapper);
+     * // => [['fred'], ['barney', 'pebbles']]
+     */
+    var partition = createAggregator(function(result, value, key) {
+      result[key ? 0 : 1].push(value);
+    }, function() { return [[], []]; });
+
+    /**
+     * Gets the property value of `path` from all elements in `collection`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {string} property The name of the property to pluck.
-     * @returns {Array} Returns a new array of property values.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * @param {Array|string} path The path of the property to pluck.
+     * @returns {Array} Returns the property values.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 40 }
      * ];
      *
-     * _.pluck(characters, 'name');
+     * _.pluck(users, 'user');
      * // => ['barney', 'fred']
-     */
-    var pluck = map;
-
-    /**
-     * Reduces a collection to a value which is the accumulated result of running
-     * each element in the collection through the callback, where each successive
-     * callback execution consumes the return value of the previous execution. If
-     * `accumulator` is not provided the first element of the collection will be
-     * used as the initial `accumulator` value. The callback is bound to `thisArg`
-     * and invoked with four arguments; (accumulator, value, index|key, collection).
+     *
+     * var userIndex = _.indexBy(users, 'user');
+     * _.pluck(userIndex, 'age');
+     * // => [36, 40] (iteration order is not guaranteed)
+     */
+    function pluck(collection, path) {
+      return map(collection, property(path));
+    }
+
+    /**
+     * Reduces `collection` to a value which is the accumulated result of running
+     * each element in `collection` through `iteratee`, where each successive
+     * invocation is supplied the return value of the previous. If `accumulator`
+     * is not provided the first element of `collection` is used as the initial
+     * value. The `iteratee` is bound to `thisArg` and invoked with four arguments:
+     * (accumulator, value, index|key, collection).
+     *
+     * Many lodash methods are guarded to work as iteratees for methods like
+     * `_.reduce`, `_.reduceRight`, and `_.transform`.
+     *
+     * The guarded methods are:
+     * `assign`, `defaults`, `defaultsDeep`, `includes`, `merge`, `sortByAll`,
+     * and `sortByOrder`
      *
      * @static
      * @memberOf _
      * @alias foldl, inject
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [accumulator] Initial value of the accumulator.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [accumulator] The initial value.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {*} Returns the accumulated value.
      * @example
      *
-     * var sum = _.reduce([1, 2, 3], function(sum, num) {
-     *   return sum + num;
+     * _.reduce([1, 2], function(total, n) {
+     *   return total + n;
      * });
-     * // => 6
-     *
-     * var mapped = _.reduce({ 'a': 1, 'b': 2, 'c': 3 }, function(result, num, key) {
-     *   result[key] = num * 3;
+     * // => 3
+     *
+     * _.reduce({ 'a': 1, 'b': 2 }, function(result, n, key) {
+     *   result[key] = n * 3;
      *   return result;
      * }, {});
-     * // => { 'a': 3, 'b': 6, 'c': 9 }
-     */
-    function reduce(collection, callback, accumulator, thisArg) {
-      if (!collection) return accumulator;
-      var noaccum = arguments.length < 3;
-      callback = lodash.createCallback(callback, thisArg, 4);
-
-      var index = -1,
-          length = collection.length;
-
-      if (typeof length == 'number') {
-        if (noaccum) {
-          accumulator = collection[++index];
-        }
-        while (++index < length) {
-          accumulator = callback(accumulator, collection[index], index, collection);
-        }
-      } else {
-        forOwn(collection, function(value, index, collection) {
-          accumulator = noaccum
-            ? (noaccum = false, value)
-            : callback(accumulator, value, index, collection)
-        });
-      }
-      return accumulator;
-    }
-
-    /**
-     * This method is like `_.reduce` except that it iterates over elements
-     * of a `collection` from right to left.
+     * // => { 'a': 3, 'b': 6 } (iteration order is not guaranteed)
+     */
+    var reduce = createReduce(arrayReduce, baseEach);
+
+    /**
+     * This method is like `_.reduce` except that it iterates over elements of
+     * `collection` from right to left.
      *
      * @static
      * @memberOf _
      * @alias foldr
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function} [callback=identity] The function called per iteration.
-     * @param {*} [accumulator] Initial value of the accumulator.
-     * @param {*} [thisArg] The `this` binding of `callback`.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [accumulator] The initial value.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
      * @returns {*} Returns the accumulated value.
      * @example
      *
-     * var list = [[0, 1], [2, 3], [4, 5]];
-     * var flat = _.reduceRight(list, function(a, b) { return a.concat(b); }, []);
+     * var array = [[0, 1], [2, 3], [4, 5]];
+     *
+     * _.reduceRight(array, function(flattened, other) {
+     *   return flattened.concat(other);
+     * }, []);
      * // => [4, 5, 2, 3, 0, 1]
      */
-    function reduceRight(collection, callback, accumulator, thisArg) {
-      var noaccum = arguments.length < 3;
-      callback = lodash.createCallback(callback, thisArg, 4);
-      forEachRight(collection, function(value, index, collection) {
-        accumulator = noaccum
-          ? (noaccum = false, value)
-          : callback(accumulator, value, index, collection);
+    var reduceRight = createReduce(arrayReduceRight, baseEachRight);
+
+    /**
+     * The opposite of `_.filter`; this method returns the elements of `collection`
+     * that `predicate` does **not** return truthy for.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Array} Returns the new filtered array.
+     * @example
+     *
+     * _.reject([1, 2, 3, 4], function(n) {
+     *   return n % 2 == 0;
+     * });
+     * // => [1, 3]
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': false },
+     *   { 'user': 'fred',   'age': 40, 'active': true }
+     * ];
+     *
+     * // using the `_.matches` callback shorthand
+     * _.pluck(_.reject(users, { 'age': 40, 'active': true }), 'user');
+     * // => ['barney']
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.pluck(_.reject(users, 'active', false), 'user');
+     * // => ['fred']
+     *
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.reject(users, 'active'), 'user');
+     * // => ['barney']
+     */
+    function reject(collection, predicate, thisArg) {
+      var func = isArray(collection) ? arrayFilter : baseFilter;
+      predicate = getCallback(predicate, thisArg, 3);
+      return func(collection, function(value, index, collection) {
+        return !predicate(value, index, collection);
       });
-      return accumulator;
-    }
-
-    /**
-     * The opposite of `_.filter` this method returns the elements of a
-     * collection that the callback does **not** return truey for.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of elements that failed the callback check.
-     * @example
-     *
-     * var odds = _.reject([1, 2, 3, 4, 5, 6], function(num) { return num % 2 == 0; });
-     * // => [1, 3, 5]
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'blocked': false },
-     *   { 'name': 'fred',   'age': 40, 'blocked': true }
-     * ];
-     *
-     * // using "_.pluck" callback shorthand
-     * _.reject(characters, 'blocked');
-     * // => [{ 'name': 'barney', 'age': 36, 'blocked': false }]
-     *
-     * // using "_.where" callback shorthand
-     * _.reject(characters, { 'age': 36 });
-     * // => [{ 'name': 'fred', 'age': 40, 'blocked': true }]
-     */
-    function reject(collection, callback, thisArg) {
-      callback = lodash.createCallback(callback, thisArg, 3);
-      return filter(collection, function(value, index, collection) {
-        return !callback(value, index, collection);
-      });
-    }
-
-    /**
-     * Retrieves a random element or `n` random elements from a collection.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+    }
+
+    /**
+     * Gets a random element or `n` random elements from a collection.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to sample.
      * @param {number} [n] The number of elements to sample.
-     * @param- {Object} [guard] Allows working with functions like `_.map`
-     *  without using their `index` arguments as `n`.
-     * @returns {Array} Returns the random sample(s) of `collection`.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {*} Returns the random sample(s).
      * @example
      *
      * _.sample([1, 2, 3, 4]);
@@ -3839,1287 +6927,354 @@
      * // => [3, 1]
      */
     function sample(collection, n, guard) {
-      if (collection && typeof collection.length != 'number') {
-        collection = values(collection);
-      }
-      if (n == null || guard) {
-        return collection ? collection[baseRandom(0, collection.length - 1)] : undefined;
-      }
-      var result = shuffle(collection);
-      result.length = nativeMin(nativeMax(0, n), result.length);
+      if (guard ? isIterateeCall(collection, n, guard) : n == null) {
+        collection = toIterable(collection);
+        var length = collection.length;
+        return length > 0 ? collection[baseRandom(0, length - 1)] : undefined;
+      }
+      var index = -1,
+          result = toArray(collection),
+          length = result.length,
+          lastIndex = length - 1;
+
+      n = nativeMin(n < 0 ? 0 : (+n || 0), length);
+      while (++index < n) {
+        var rand = baseRandom(index, lastIndex),
+            value = result[rand];
+
+        result[rand] = result[index];
+        result[index] = value;
+      }
+      result.length = n;
       return result;
     }
 
     /**
-     * Creates an array of shuffled values, using a version of the Fisher-Yates
-     * shuffle. See http://en.wikipedia.org/wiki/Fisher-Yates_shuffle.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * Creates an array of shuffled values, using a version of the
+     * [Fisher-Yates shuffle](https://en.wikipedia.org/wiki/Fisher-Yates_shuffle).
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to shuffle.
-     * @returns {Array} Returns a new shuffled collection.
-     * @example
-     *
-     * _.shuffle([1, 2, 3, 4, 5, 6]);
-     * // => [4, 1, 6, 3, 5, 2]
+     * @returns {Array} Returns the new shuffled array.
+     * @example
+     *
+     * _.shuffle([1, 2, 3, 4]);
+     * // => [4, 1, 3, 2]
      */
     function shuffle(collection) {
-      var index = -1,
-          length = collection ? collection.length : 0,
-          result = Array(typeof length == 'number' ? length : 0);
-
-      forEach(collection, function(value) {
-        var rand = baseRandom(0, ++index);
-        result[index] = result[rand];
-        result[rand] = value;
-      });
-      return result;
-    }
-
-    /**
-     * Gets the size of the `collection` by returning `collection.length` for arrays
-     * and array-like objects or the number of own enumerable properties for objects.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+      return sample(collection, POSITIVE_INFINITY);
+    }
+
+    /**
+     * Gets the size of `collection` by returning its length for array-like
+     * values or the number of own enumerable properties for objects.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to inspect.
-     * @returns {number} Returns `collection.length` or number of own enumerable properties.
-     * @example
-     *
-     * _.size([1, 2]);
+     * @returns {number} Returns the size of `collection`.
+     * @example
+     *
+     * _.size([1, 2, 3]);
+     * // => 3
+     *
+     * _.size({ 'a': 1, 'b': 2 });
      * // => 2
      *
-     * _.size({ 'one': 1, 'two': 2, 'three': 3 });
-     * // => 3
-     *
      * _.size('pebbles');
      * // => 7
      */
     function size(collection) {
-      var length = collection ? collection.length : 0;
-      return typeof length == 'number' ? length : keys(collection).length;
-    }
-
-    /**
-     * Checks if the callback returns a truey value for **any** element of a
-     * collection. The function returns as soon as it finds a passing value and
-     * does not iterate over the entire collection. The callback is bound to
-     * `thisArg` and invoked with three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
+      var length = collection ? getLength(collection) : 0;
+      return isLength(length) ? length : keys(collection).length;
+    }
+
+    /**
+     * Checks if `predicate` returns truthy for **any** element of `collection`.
+     * The function returns as soon as it finds a passing value and does not iterate
+     * over the entire collection. The predicate is bound to `thisArg` and invoked
+     * with three arguments: (value, index|key, collection).
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
      *
      * @static
      * @memberOf _
      * @alias any
-     * @category Collections
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {boolean} Returns `true` if any element passed the callback check,
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {boolean} Returns `true` if any element passes the predicate check,
      *  else `false`.
      * @example
      *
      * _.some([null, 0, 'yes', false], Boolean);
      * // => true
      *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'blocked': false },
-     *   { 'name': 'fred',   'age': 40, 'blocked': true }
+     * var users = [
+     *   { 'user': 'barney', 'active': true },
+     *   { 'user': 'fred',   'active': false }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.some(characters, 'blocked');
-     * // => true
-     *
-     * // using "_.where" callback shorthand
-     * _.some(characters, { 'age': 1 });
+     * // using the `_.matches` callback shorthand
+     * _.some(users, { 'user': 'barney', 'active': false });
      * // => false
-     */
-    function some(collection, callback, thisArg) {
-      var result;
-      callback = lodash.createCallback(callback, thisArg, 3);
-
-      var index = -1,
-          length = collection ? collection.length : 0;
-
-      if (typeof length == 'number') {
-        while (++index < length) {
-          if ((result = callback(collection[index], index, collection))) {
-            break;
-          }
-        }
-      } else {
-        forOwn(collection, function(value, index, collection) {
-          return !(result = callback(value, index, collection));
-        });
-      }
-      return !!result;
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.some(users, 'active', false);
+     * // => true
+     *
+     * // using the `_.property` callback shorthand
+     * _.some(users, 'active');
+     * // => true
+     */
+    function some(collection, predicate, thisArg) {
+      var func = isArray(collection) ? arraySome : baseSome;
+      if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
+        predicate = undefined;
+      }
+      if (typeof predicate != 'function' || thisArg !== undefined) {
+        predicate = getCallback(predicate, thisArg, 3);
+      }
+      return func(collection, predicate);
     }
 
     /**
      * Creates an array of elements, sorted in ascending order by the results of
-     * running each element in a collection through the callback. This method
-     * performs a stable sort, that is, it will preserve the original sort order
-     * of equal elements. The callback is bound to `thisArg` and invoked with
-     * three arguments; (value, index|key, collection).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an array of property names is provided for `callback` the collection
-     * will be sorted by each property value.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
+     * running each element in a collection through `iteratee`. This method performs
+     * a stable sort, that is, it preserves the original sort order of equal elements.
+     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
+     * (value, index|key, collection).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
      * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Array|Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of sorted elements.
-     * @example
-     *
-     * _.sortBy([1, 2, 3], function(num) { return Math.sin(num); });
-     * // => [3, 1, 2]
-     *
-     * _.sortBy([1, 2, 3], function(num) { return this.sin(num); }, Math);
-     * // => [3, 1, 2]
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36 },
-     *   { 'name': 'fred',    'age': 40 },
-     *   { 'name': 'barney',  'age': 26 },
-     *   { 'name': 'fred',    'age': 30 }
-     * ];
-     *
-     * // using "_.pluck" callback shorthand
-     * _.map(_.sortBy(characters, 'age'), _.values);
-     * // => [['barney', 26], ['fred', 30], ['barney', 36], ['fred', 40]]
-     *
-     * // sorting by multiple properties
-     * _.map(_.sortBy(characters, ['name', 'age']), _.values);
-     * // = > [['barney', 26], ['barney', 36], ['fred', 30], ['fred', 40]]
-     */
-    function sortBy(collection, callback, thisArg) {
-      var index = -1,
-          isArr = isArray(callback),
-          length = collection ? collection.length : 0,
-          result = Array(typeof length == 'number' ? length : 0);
-
-      if (!isArr) {
-        callback = lodash.createCallback(callback, thisArg, 3);
-      }
-      forEach(collection, function(value, key, collection) {
-        var object = result[++index] = getObject();
-        if (isArr) {
-          object.criteria = map(callback, function(key) { return value[key]; });
-        } else {
-          (object.criteria = getArray())[0] = callback(value, key, collection);
-        }
-        object.index = index;
-        object.value = value;
-      });
-
-      length = result.length;
-      result.sort(compareAscending);
-      while (length--) {
-        var object = result[length];
-        result[length] = object.value;
-        if (!isArr) {
-          releaseArray(object.criteria);
-        }
-        releaseObject(object);
-      }
-      return result;
-    }
-
-    /**
-     * Converts the `collection` to an array.
-     *
-     * @static
-     * @memberOf _
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to convert.
-     * @returns {Array} Returns the new converted array.
-     * @example
-     *
-     * (function() { return _.toArray(arguments).slice(1); })(1, 2, 3, 4);
-     * // => [2, 3, 4]
-     */
-    function toArray(collection) {
-      if (collection && typeof collection.length == 'number') {
-        return slice(collection);
-      }
-      return values(collection);
-    }
-
-    /**
-     * Performs a deep comparison of each element in a `collection` to the given
-     * `properties` object, returning an array of all elements that have equivalent
-     * property values.
-     *
-     * @static
-     * @memberOf _
-     * @type Function
-     * @category Collections
-     * @param {Array|Object|string} collection The collection to iterate over.
-     * @param {Object} props The object of property values to filter by.
-     * @returns {Array} Returns a new array of elements that have the given properties.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36, 'pets': ['hoppy'] },
-     *   { 'name': 'fred',   'age': 40, 'pets': ['baby puss', 'dino'] }
-     * ];
-     *
-     * _.where(characters, { 'age': 36 });
-     * // => [{ 'name': 'barney', 'age': 36, 'pets': ['hoppy'] }]
-     *
-     * _.where(characters, { 'pets': ['dino'] });
-     * // => [{ 'name': 'fred', 'age': 40, 'pets': ['baby puss', 'dino'] }]
-     */
-    var where = filter;
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates an array with all falsey values removed. The values `false`, `null`,
-     * `0`, `""`, `undefined`, and `NaN` are all falsey.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to compact.
-     * @returns {Array} Returns a new array of filtered values.
-     * @example
-     *
-     * _.compact([0, 1, false, 2, '', 3]);
-     * // => [1, 2, 3]
-     */
-    function compact(array) {
-      var index = -1,
-          length = array ? array.length : 0,
-          result = [];
-
-      while (++index < length) {
-        var value = array[index];
-        if (value) {
-          result.push(value);
-        }
-      }
-      return result;
-    }
-
-    /**
-     * Creates an array excluding all values of the provided arrays using strict
-     * equality for comparisons, i.e. `===`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to process.
-     * @param {...Array} [values] The arrays of values to exclude.
-     * @returns {Array} Returns a new array of filtered values.
-     * @example
-     *
-     * _.difference([1, 2, 3, 4, 5], [5, 2, 10]);
-     * // => [1, 3, 4]
-     */
-    function difference(array) {
-      return baseDifference(array, baseFlatten(arguments, true, true, 1));
-    }
-
-    /**
-     * This method is like `_.find` except that it returns the index of the first
-     * element that passes the callback check, instead of the element itself.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {number} Returns the index of the found element, else `-1`.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36, 'blocked': false },
-     *   { 'name': 'fred',    'age': 40, 'blocked': true },
-     *   { 'name': 'pebbles', 'age': 1,  'blocked': false }
-     * ];
-     *
-     * _.findIndex(characters, function(chr) {
-     *   return chr.age < 20;
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the new sorted array.
+     * @example
+     *
+     * _.sortBy([1, 2, 3], function(n) {
+     *   return Math.sin(n);
      * });
-     * // => 2
-     *
-     * // using "_.where" callback shorthand
-     * _.findIndex(characters, { 'age': 36 });
-     * // => 0
-     *
-     * // using "_.pluck" callback shorthand
-     * _.findIndex(characters, 'blocked');
-     * // => 1
-     */
-    function findIndex(array, callback, thisArg) {
-      var index = -1,
-          length = array ? array.length : 0;
-
-      callback = lodash.createCallback(callback, thisArg, 3);
-      while (++index < length) {
-        if (callback(array[index], index, array)) {
-          return index;
-        }
-      }
-      return -1;
-    }
-
-    /**
-     * This method is like `_.findIndex` except that it iterates over elements
-     * of a `collection` from right to left.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {number} Returns the index of the found element, else `-1`.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36, 'blocked': true },
-     *   { 'name': 'fred',    'age': 40, 'blocked': false },
-     *   { 'name': 'pebbles', 'age': 1,  'blocked': true }
-     * ];
-     *
-     * _.findLastIndex(characters, function(chr) {
-     *   return chr.age > 30;
-     * });
-     * // => 1
-     *
-     * // using "_.where" callback shorthand
-     * _.findLastIndex(characters, { 'age': 36 });
-     * // => 0
-     *
-     * // using "_.pluck" callback shorthand
-     * _.findLastIndex(characters, 'blocked');
-     * // => 2
-     */
-    function findLastIndex(array, callback, thisArg) {
-      var length = array ? array.length : 0;
-      callback = lodash.createCallback(callback, thisArg, 3);
-      while (length--) {
-        if (callback(array[length], length, array)) {
-          return length;
-        }
-      }
-      return -1;
-    }
-
-    /**
-     * Gets the first element or first `n` elements of an array. If a callback
-     * is provided elements at the beginning of the array are returned as long
-     * as the callback returns truey. The callback is bound to `thisArg` and
-     * invoked with three arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @alias head, take
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback] The function called
-     *  per element or the number of elements to return. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the first element(s) of `array`.
-     * @example
-     *
-     * _.first([1, 2, 3]);
-     * // => 1
-     *
-     * _.first([1, 2, 3], 2);
-     * // => [1, 2]
-     *
-     * _.first([1, 2, 3], function(num) {
-     *   return num < 3;
-     * });
-     * // => [1, 2]
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': false, 'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true,  'employer': 'na' }
+     * // => [3, 1, 2]
+     *
+     * _.sortBy([1, 2, 3], function(n) {
+     *   return this.sin(n);
+     * }, Math);
+     * // => [3, 1, 2]
+     *
+     * var users = [
+     *   { 'user': 'fred' },
+     *   { 'user': 'pebbles' },
+     *   { 'user': 'barney' }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.first(characters, 'blocked');
-     * // => [{ 'name': 'barney', 'blocked': true, 'employer': 'slate' }]
-     *
-     * // using "_.where" callback shorthand
-     * _.pluck(_.first(characters, { 'employer': 'slate' }), 'name');
-     * // => ['barney', 'fred']
-     */
-    function first(array, callback, thisArg) {
-      var n = 0,
-          length = array ? array.length : 0;
-
-      if (typeof callback != 'number' && callback != null) {
-        var index = -1;
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (++index < length && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = callback;
-        if (n == null || thisArg) {
-          return array ? array[0] : undefined;
-        }
-      }
-      return slice(array, 0, nativeMin(nativeMax(0, n), length));
-    }
-
-    /**
-     * Flattens a nested array (the nesting can be to any depth). If `isShallow`
-     * is truey, the array will only be flattened a single level. If a callback
-     * is provided each element of the array is passed through the callback before
-     * flattening. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to flatten.
-     * @param {boolean} [isShallow=false] A flag to restrict flattening to a single level.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new flattened array.
-     * @example
-     *
-     * _.flatten([1, [2], [3, [[4]]]]);
-     * // => [1, 2, 3, 4];
-     *
-     * _.flatten([1, [2], [3, [[4]]]], true);
-     * // => [1, 2, 3, [[4]]];
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 30, 'pets': ['hoppy'] },
-     *   { 'name': 'fred',   'age': 40, 'pets': ['baby puss', 'dino'] }
-     * ];
-     *
-     * // using "_.pluck" callback shorthand
-     * _.flatten(characters, 'pets');
-     * // => ['hoppy', 'baby puss', 'dino']
-     */
-    function flatten(array, isShallow, callback, thisArg) {
-      // juggle arguments
-      if (typeof isShallow != 'boolean' && isShallow != null) {
-        thisArg = callback;
-        callback = (typeof isShallow != 'function' && thisArg && thisArg[isShallow] === array) ? null : isShallow;
-        isShallow = false;
-      }
-      if (callback != null) {
-        array = map(array, callback, thisArg);
-      }
-      return baseFlatten(array, isShallow);
-    }
-
-    /**
-     * Gets the index at which the first occurrence of `value` is found using
-     * strict equality for comparisons, i.e. `===`. If the array is already sorted
-     * providing `true` for `fromIndex` will run a faster binary search.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {*} value The value to search for.
-     * @param {boolean|number} [fromIndex=0] The index to search from or `true`
-     *  to perform a binary search on a sorted array.
-     * @returns {number} Returns the index of the matched value or `-1`.
-     * @example
-     *
-     * _.indexOf([1, 2, 3, 1, 2, 3], 2);
-     * // => 1
-     *
-     * _.indexOf([1, 2, 3, 1, 2, 3], 2, 3);
-     * // => 4
-     *
-     * _.indexOf([1, 1, 2, 2, 3, 3], 2, true);
-     * // => 2
-     */
-    function indexOf(array, value, fromIndex) {
-      if (typeof fromIndex == 'number') {
-        var length = array ? array.length : 0;
-        fromIndex = (fromIndex < 0 ? nativeMax(0, length + fromIndex) : fromIndex || 0);
-      } else if (fromIndex) {
-        var index = sortedIndex(array, value);
-        return array[index] === value ? index : -1;
-      }
-      return baseIndexOf(array, value, fromIndex);
-    }
-
-    /**
-     * Gets all but the last element or last `n` elements of an array. If a
-     * callback is provided elements at the end of the array are excluded from
-     * the result as long as the callback returns truey. The callback is bound
-     * to `thisArg` and invoked with three arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback=1] The function called
-     *  per element or the number of elements to exclude. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a slice of `array`.
-     * @example
-     *
-     * _.initial([1, 2, 3]);
-     * // => [1, 2]
-     *
-     * _.initial([1, 2, 3], 2);
-     * // => [1]
-     *
-     * _.initial([1, 2, 3], function(num) {
-     *   return num > 1;
-     * });
-     * // => [1]
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': false, 'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true,  'employer': 'na' }
+     * // using the `_.property` callback shorthand
+     * _.pluck(_.sortBy(users, 'user'), 'user');
+     * // => ['barney', 'fred', 'pebbles']
+     */
+    function sortBy(collection, iteratee, thisArg) {
+      if (collection == null) {
+        return [];
+      }
+      if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
+        iteratee = undefined;
+      }
+      var index = -1;
+      iteratee = getCallback(iteratee, thisArg, 3);
+
+      var result = baseMap(collection, function(value, key, collection) {
+        return { 'criteria': iteratee(value, key, collection), 'index': ++index, 'value': value };
+      });
+      return baseSortBy(result, compareAscending);
+    }
+
+    /**
+     * This method is like `_.sortBy` except that it can sort by multiple iteratees
+     * or property names.
+     *
+     * If a property name is provided for an iteratee the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If an object is provided for an iteratee the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {...(Function|Function[]|Object|Object[]|string|string[])} iteratees
+     *  The iteratees to sort by, specified as individual values or arrays of values.
+     * @returns {Array} Returns the new sorted array.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'fred',   'age': 48 },
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 42 },
+     *   { 'user': 'barney', 'age': 34 }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.initial(characters, 'blocked');
-     * // => [{ 'name': 'barney',  'blocked': false, 'employer': 'slate' }]
-     *
-     * // using "_.where" callback shorthand
-     * _.pluck(_.initial(characters, { 'employer': 'na' }), 'name');
-     * // => ['barney', 'fred']
-     */
-    function initial(array, callback, thisArg) {
-      var n = 0,
-          length = array ? array.length : 0;
-
-      if (typeof callback != 'number' && callback != null) {
-        var index = length;
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (index-- && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = (callback == null || thisArg) ? 1 : callback || n;
-      }
-      return slice(array, 0, nativeMin(nativeMax(0, length - n), length));
-    }
-
-    /**
-     * Creates an array of unique values present in all provided arrays using
-     * strict equality for comparisons, i.e. `===`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {...Array} [array] The arrays to inspect.
-     * @returns {Array} Returns an array of shared values.
-     * @example
-     *
-     * _.intersection([1, 2, 3], [5, 2, 1, 4], [2, 1]);
-     * // => [1, 2]
-     */
-    function intersection() {
-      var args = [],
-          argsIndex = -1,
-          argsLength = arguments.length,
-          caches = getArray(),
-          indexOf = getIndexOf(),
-          trustIndexOf = indexOf === baseIndexOf,
-          seen = getArray();
-
-      while (++argsIndex < argsLength) {
-        var value = arguments[argsIndex];
-        if (isArray(value) || isArguments(value)) {
-          args.push(value);
-          caches.push(trustIndexOf && value.length >= largeArraySize &&
-            createCache(argsIndex ? args[argsIndex] : seen));
-        }
-      }
-      var array = args[0],
-          index = -1,
-          length = array ? array.length : 0,
-          result = [];
-
-      outer:
-      while (++index < length) {
-        var cache = caches[0];
-        value = array[index];
-
-        if ((cache ? cacheIndexOf(cache, value) : indexOf(seen, value)) < 0) {
-          argsIndex = argsLength;
-          (cache || seen).push(value);
-          while (--argsIndex) {
-            cache = caches[argsIndex];
-            if ((cache ? cacheIndexOf(cache, value) : indexOf(args[argsIndex], value)) < 0) {
-              continue outer;
-            }
-          }
-          result.push(value);
-        }
-      }
-      while (argsLength--) {
-        cache = caches[argsLength];
-        if (cache) {
-          releaseObject(cache);
-        }
-      }
-      releaseArray(caches);
-      releaseArray(seen);
-      return result;
-    }
-
-    /**
-     * Gets the last element or last `n` elements of an array. If a callback is
-     * provided elements at the end of the array are returned as long as the
-     * callback returns truey. The callback is bound to `thisArg` and invoked
-     * with three arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback] The function called
-     *  per element or the number of elements to return. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {*} Returns the last element(s) of `array`.
-     * @example
-     *
-     * _.last([1, 2, 3]);
-     * // => 3
-     *
-     * _.last([1, 2, 3], 2);
-     * // => [2, 3]
-     *
-     * _.last([1, 2, 3], function(num) {
-     *   return num > 1;
-     * });
-     * // => [2, 3]
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': false, 'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true,  'employer': 'na' }
+     * _.map(_.sortByAll(users, ['user', 'age']), _.values);
+     * // => [['barney', 34], ['barney', 36], ['fred', 42], ['fred', 48]]
+     *
+     * _.map(_.sortByAll(users, 'user', function(chr) {
+     *   return Math.floor(chr.age / 10);
+     * }), _.values);
+     * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
+     */
+    var sortByAll = restParam(function(collection, iteratees) {
+      if (collection == null) {
+        return [];
+      }
+      var guard = iteratees[2];
+      if (guard && isIterateeCall(iteratees[0], iteratees[1], guard)) {
+        iteratees.length = 1;
+      }
+      return baseSortByOrder(collection, baseFlatten(iteratees), []);
+    });
+
+    /**
+     * This method is like `_.sortByAll` except that it allows specifying the
+     * sort orders of the iteratees to sort by. If `orders` is unspecified, all
+     * values are sorted in ascending order. Otherwise, a value is sorted in
+     * ascending order if its corresponding order is "asc", and descending if "desc".
+     *
+     * If a property name is provided for an iteratee the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If an object is provided for an iteratee the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
+     * @param {boolean[]} [orders] The sort orders of `iteratees`.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
+     * @returns {Array} Returns the new sorted array.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'fred',   'age': 48 },
+     *   { 'user': 'barney', 'age': 34 },
+     *   { 'user': 'fred',   'age': 42 },
+     *   { 'user': 'barney', 'age': 36 }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.pluck(_.last(characters, 'blocked'), 'name');
-     * // => ['fred', 'pebbles']
-     *
-     * // using "_.where" callback shorthand
-     * _.last(characters, { 'employer': 'na' });
-     * // => [{ 'name': 'pebbles', 'blocked': true, 'employer': 'na' }]
-     */
-    function last(array, callback, thisArg) {
-      var n = 0,
-          length = array ? array.length : 0;
-
-      if (typeof callback != 'number' && callback != null) {
-        var index = length;
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (index-- && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = callback;
-        if (n == null || thisArg) {
-          return array ? array[length - 1] : undefined;
-        }
-      }
-      return slice(array, nativeMax(0, length - n));
-    }
-
-    /**
-     * Gets the index at which the last occurrence of `value` is found using strict
-     * equality for comparisons, i.e. `===`. If `fromIndex` is negative, it is used
-     * as the offset from the end of the collection.
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to search.
-     * @param {*} value The value to search for.
-     * @param {number} [fromIndex=array.length-1] The index to search from.
-     * @returns {number} Returns the index of the matched value or `-1`.
-     * @example
-     *
-     * _.lastIndexOf([1, 2, 3, 1, 2, 3], 2);
-     * // => 4
-     *
-     * _.lastIndexOf([1, 2, 3, 1, 2, 3], 2, 3);
-     * // => 1
-     */
-    function lastIndexOf(array, value, fromIndex) {
-      var index = array ? array.length : 0;
-      if (typeof fromIndex == 'number') {
-        index = (fromIndex < 0 ? nativeMax(0, index + fromIndex) : nativeMin(fromIndex, index - 1)) + 1;
-      }
-      while (index--) {
-        if (array[index] === value) {
-          return index;
-        }
-      }
-      return -1;
-    }
-
-    /**
-     * Removes all provided values from the given array using strict equality for
-     * comparisons, i.e. `===`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to modify.
-     * @param {...*} [value] The values to remove.
-     * @returns {Array} Returns `array`.
-     * @example
-     *
-     * var array = [1, 2, 3, 1, 2, 3];
-     * _.pull(array, 2, 3);
-     * console.log(array);
-     * // => [1, 1]
-     */
-    function pull(array) {
-      var args = arguments,
-          argsIndex = 0,
-          argsLength = args.length,
-          length = array ? array.length : 0;
-
-      while (++argsIndex < argsLength) {
-        var index = -1,
-            value = args[argsIndex];
-        while (++index < length) {
-          if (array[index] === value) {
-            splice.call(array, index--, 1);
-            length--;
-          }
-        }
-      }
-      return array;
-    }
-
-    /**
-     * Creates an array of numbers (positive and/or negative) progressing from
-     * `start` up to but not including `end`. If `start` is less than `stop` a
-     * zero-length range is created unless a negative `step` is specified.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {number} [start=0] The start of the range.
-     * @param {number} end The end of the range.
-     * @param {number} [step=1] The value to increment or decrement by.
-     * @returns {Array} Returns a new range array.
-     * @example
-     *
-     * _.range(4);
-     * // => [0, 1, 2, 3]
-     *
-     * _.range(1, 5);
-     * // => [1, 2, 3, 4]
-     *
-     * _.range(0, 20, 5);
-     * // => [0, 5, 10, 15]
-     *
-     * _.range(0, -4, -1);
-     * // => [0, -1, -2, -3]
-     *
-     * _.range(1, 4, 0);
-     * // => [1, 1, 1]
-     *
-     * _.range(0);
-     * // => []
-     */
-    function range(start, end, step) {
-      start = +start || 0;
-      step = typeof step == 'number' ? step : (+step || 1);
-
-      if (end == null) {
-        end = start;
-        start = 0;
-      }
-      // use `Array(length)` so engines like Chakra and V8 avoid slower modes
-      // http://youtu.be/XAqIpGU8ZZk#t=17m25s
-      var index = -1,
-          length = nativeMax(0, ceil((end - start) / (step || 1))),
-          result = Array(length);
-
-      while (++index < length) {
-        result[index] = start;
-        start += step;
-      }
-      return result;
-    }
-
-    /**
-     * Removes all elements from an array that the callback returns truey for
-     * and returns an array of removed elements. The callback is bound to `thisArg`
-     * and invoked with three arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to modify.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a new array of removed elements.
-     * @example
-     *
-     * var array = [1, 2, 3, 4, 5, 6];
-     * var evens = _.remove(array, function(num) { return num % 2 == 0; });
-     *
-     * console.log(array);
-     * // => [1, 3, 5]
-     *
-     * console.log(evens);
-     * // => [2, 4, 6]
-     */
-    function remove(array, callback, thisArg) {
-      var index = -1,
-          length = array ? array.length : 0,
-          result = [];
-
-      callback = lodash.createCallback(callback, thisArg, 3);
-      while (++index < length) {
-        var value = array[index];
-        if (callback(value, index, array)) {
-          result.push(value);
-          splice.call(array, index--, 1);
-          length--;
-        }
-      }
-      return result;
-    }
-
-    /**
-     * The opposite of `_.initial` this method gets all but the first element or
-     * first `n` elements of an array. If a callback function is provided elements
-     * at the beginning of the array are excluded from the result as long as the
-     * callback returns truey. The callback is bound to `thisArg` and invoked
-     * with three arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @alias drop, tail
-     * @category Arrays
-     * @param {Array} array The array to query.
-     * @param {Function|Object|number|string} [callback=1] The function called
-     *  per element or the number of elements to exclude. If a property name or
-     *  object is provided it will be used to create a "_.pluck" or "_.where"
-     *  style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a slice of `array`.
-     * @example
-     *
-     * _.rest([1, 2, 3]);
-     * // => [2, 3]
-     *
-     * _.rest([1, 2, 3], 2);
-     * // => [3]
-     *
-     * _.rest([1, 2, 3], function(num) {
-     *   return num < 3;
-     * });
-     * // => [3]
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'blocked': true,  'employer': 'slate' },
-     *   { 'name': 'fred',    'blocked': false,  'employer': 'slate' },
-     *   { 'name': 'pebbles', 'blocked': true, 'employer': 'na' }
+     * // sort by `user` in ascending order and by `age` in descending order
+     * _.map(_.sortByOrder(users, ['user', 'age'], ['asc', 'desc']), _.values);
+     * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
+     */
+    function sortByOrder(collection, iteratees, orders, guard) {
+      if (collection == null) {
+        return [];
+      }
+      if (guard && isIterateeCall(iteratees, orders, guard)) {
+        orders = undefined;
+      }
+      if (!isArray(iteratees)) {
+        iteratees = iteratees == null ? [] : [iteratees];
+      }
+      if (!isArray(orders)) {
+        orders = orders == null ? [] : [orders];
+      }
+      return baseSortByOrder(collection, iteratees, orders);
+    }
+
+    /**
+     * Performs a deep comparison between each element in `collection` and the
+     * source object, returning an array of all elements that have equivalent
+     * property values.
+     *
+     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
+     * numbers, `Object` objects, regexes, and strings. Objects are compared by
+     * their own, not inherited, enumerable properties. For comparing a single
+     * own or inherited property value see `_.matchesProperty`.
+     *
+     * @static
+     * @memberOf _
+     * @category Collection
+     * @param {Array|Object|string} collection The collection to search.
+     * @param {Object} source The object of property values to match.
+     * @returns {Array} Returns the new filtered array.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': false, 'pets': ['hoppy'] },
+     *   { 'user': 'fred',   'age': 40, 'active': true, 'pets': ['baby puss', 'dino'] }
      * ];
      *
-     * // using "_.pluck" callback shorthand
-     * _.pluck(_.rest(characters, 'blocked'), 'name');
-     * // => ['fred', 'pebbles']
-     *
-     * // using "_.where" callback shorthand
-     * _.rest(characters, { 'employer': 'slate' });
-     * // => [{ 'name': 'pebbles', 'blocked': true, 'employer': 'na' }]
-     */
-    function rest(array, callback, thisArg) {
-      if (typeof callback != 'number' && callback != null) {
-        var n = 0,
-            index = -1,
-            length = array ? array.length : 0;
-
-        callback = lodash.createCallback(callback, thisArg, 3);
-        while (++index < length && callback(array[index], index, array)) {
-          n++;
-        }
-      } else {
-        n = (callback == null || thisArg) ? 1 : nativeMax(0, callback);
-      }
-      return slice(array, n);
-    }
-
-    /**
-     * Uses a binary search to determine the smallest index at which a value
-     * should be inserted into a given sorted array in order to maintain the sort
-     * order of the array. If a callback is provided it will be executed for
-     * `value` and each element of `array` to compute their sort ranking. The
-     * callback is bound to `thisArg` and invoked with one argument; (value).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to inspect.
-     * @param {*} value The value to evaluate.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {number} Returns the index at which `value` should be inserted
-     *  into `array`.
-     * @example
-     *
-     * _.sortedIndex([20, 30, 50], 40);
-     * // => 2
-     *
-     * // using "_.pluck" callback shorthand
-     * _.sortedIndex([{ 'x': 20 }, { 'x': 30 }, { 'x': 50 }], { 'x': 40 }, 'x');
-     * // => 2
-     *
-     * var dict = {
-     *   'wordToNumber': { 'twenty': 20, 'thirty': 30, 'fourty': 40, 'fifty': 50 }
-     * };
-     *
-     * _.sortedIndex(['twenty', 'thirty', 'fifty'], 'fourty', function(word) {
-     *   return dict.wordToNumber[word];
-     * });
-     * // => 2
-     *
-     * _.sortedIndex(['twenty', 'thirty', 'fifty'], 'fourty', function(word) {
-     *   return this.wordToNumber[word];
-     * }, dict);
-     * // => 2
-     */
-    function sortedIndex(array, value, callback, thisArg) {
-      var low = 0,
-          high = array ? array.length : low;
-
-      // explicitly reference `identity` for better inlining in Firefox
-      callback = callback ? lodash.createCallback(callback, thisArg, 1) : identity;
-      value = callback(value);
-
-      while (low < high) {
-        var mid = (low + high) >>> 1;
-        (callback(array[mid]) < value)
-          ? low = mid + 1
-          : high = mid;
-      }
-      return low;
-    }
-
-    /**
-     * Creates an array of unique values, in order, of the provided arrays using
-     * strict equality for comparisons, i.e. `===`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {...Array} [array] The arrays to inspect.
-     * @returns {Array} Returns an array of combined values.
-     * @example
-     *
-     * _.union([1, 2, 3], [5, 2, 1, 4], [2, 1]);
-     * // => [1, 2, 3, 5, 4]
-     */
-    function union() {
-      return baseUniq(baseFlatten(arguments, true, true));
-    }
-
-    /**
-     * Creates a duplicate-value-free version of an array using strict equality
-     * for comparisons, i.e. `===`. If the array is sorted, providing
-     * `true` for `isSorted` will use a faster algorithm. If a callback is provided
-     * each element of `array` is passed through the callback before uniqueness
-     * is computed. The callback is bound to `thisArg` and invoked with three
-     * arguments; (value, index, array).
-     *
-     * If a property name is provided for `callback` the created "_.pluck" style
-     * callback will return the property value of the given element.
-     *
-     * If an object is provided for `callback` the created "_.where" style callback
-     * will return `true` for elements that have the properties of the given object,
-     * else `false`.
-     *
-     * @static
-     * @memberOf _
-     * @alias unique
-     * @category Arrays
-     * @param {Array} array The array to process.
-     * @param {boolean} [isSorted=false] A flag to indicate that `array` is sorted.
-     * @param {Function|Object|string} [callback=identity] The function called
-     *  per iteration. If a property name or object is provided it will be used
-     *  to create a "_.pluck" or "_.where" style callback, respectively.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns a duplicate-value-free array.
-     * @example
-     *
-     * _.uniq([1, 2, 1, 3, 1]);
-     * // => [1, 2, 3]
-     *
-     * _.uniq([1, 1, 2, 2, 3], true);
-     * // => [1, 2, 3]
-     *
-     * _.uniq(['A', 'b', 'C', 'a', 'B', 'c'], function(letter) { return letter.toLowerCase(); });
-     * // => ['A', 'b', 'C']
-     *
-     * _.uniq([1, 2.5, 3, 1.5, 2, 3.5], function(num) { return this.floor(num); }, Math);
-     * // => [1, 2.5, 3]
-     *
-     * // using "_.pluck" callback shorthand
-     * _.uniq([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
-     * // => [{ 'x': 1 }, { 'x': 2 }]
-     */
-    function uniq(array, isSorted, callback, thisArg) {
-      // juggle arguments
-      if (typeof isSorted != 'boolean' && isSorted != null) {
-        thisArg = callback;
-        callback = (typeof isSorted != 'function' && thisArg && thisArg[isSorted] === array) ? null : isSorted;
-        isSorted = false;
-      }
-      if (callback != null) {
-        callback = lodash.createCallback(callback, thisArg, 3);
-      }
-      return baseUniq(array, isSorted, callback);
-    }
-
-    /**
-     * Creates an array excluding all provided values using strict equality for
-     * comparisons, i.e. `===`.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {Array} array The array to filter.
-     * @param {...*} [value] The values to exclude.
-     * @returns {Array} Returns a new array of filtered values.
-     * @example
-     *
-     * _.without([1, 2, 1, 0, 3, 1, 4], 0, 1);
-     * // => [2, 3, 4]
-     */
-    function without(array) {
-      return baseDifference(array, slice(arguments, 1));
-    }
-
-    /**
-     * Creates an array that is the symmetric difference of the provided arrays.
-     * See http://en.wikipedia.org/wiki/Symmetric_difference.
-     *
-     * @static
-     * @memberOf _
-     * @category Arrays
-     * @param {...Array} [array] The arrays to inspect.
-     * @returns {Array} Returns an array of values.
-     * @example
-     *
-     * _.xor([1, 2, 3], [5, 2, 1, 4]);
-     * // => [3, 5, 4]
-     *
-     * _.xor([1, 2, 5], [2, 3, 5], [3, 4, 5]);
-     * // => [1, 4, 5]
-     */
-    function xor() {
-      var index = -1,
-          length = arguments.length;
-
-      while (++index < length) {
-        var array = arguments[index];
-        if (isArray(array) || isArguments(array)) {
-          var result = result
-            ? baseUniq(baseDifference(result, array).concat(baseDifference(array, result)))
-            : array;
-        }
-      }
-      return result || [];
-    }
-
-    /**
-     * Creates an array of grouped elements, the first of which contains the first
-     * elements of the given arrays, the second of which contains the second
-     * elements of the given arrays, and so on.
-     *
-     * @static
-     * @memberOf _
-     * @alias unzip
-     * @category Arrays
-     * @param {...Array} [array] Arrays to process.
-     * @returns {Array} Returns a new array of grouped elements.
-     * @example
-     *
-     * _.zip(['fred', 'barney'], [30, 40], [true, false]);
-     * // => [['fred', 30, true], ['barney', 40, false]]
-     */
-    function zip() {
-      var array = arguments.length > 1 ? arguments : arguments[0],
-          index = -1,
-          length = array ? max(pluck(array, 'length')) : 0,
-          result = Array(length < 0 ? 0 : length);
-
-      while (++index < length) {
-        result[index] = pluck(array, index);
-      }
-      return result;
-    }
-
-    /**
-     * Creates an object composed from arrays of `keys` and `values`. Provide
-     * either a single two dimensional array, i.e. `[[key1, value1], [key2, value2]]`
-     * or two arrays, one of `keys` and one of corresponding `values`.
-     *
-     * @static
-     * @memberOf _
-     * @alias object
-     * @category Arrays
-     * @param {Array} keys The array of keys.
-     * @param {Array} [values=[]] The array of values.
-     * @returns {Object} Returns an object composed of the given keys and
-     *  corresponding values.
-     * @example
-     *
-     * _.zipObject(['fred', 'barney'], [30, 40]);
-     * // => { 'fred': 30, 'barney': 40 }
-     */
-    function zipObject(keys, values) {
-      var index = -1,
-          length = keys ? keys.length : 0,
-          result = {};
-
-      if (!values && length && !isArray(keys[0])) {
-        values = [];
-      }
-      while (++index < length) {
-        var key = keys[index];
-        if (values) {
-          result[key] = values[index];
-        } else if (key) {
-          result[key[0]] = key[1];
-        }
-      }
-      return result;
-    }
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates a function that executes `func`, with  the `this` binding and
-     * arguments of the created function, only after being called `n` times.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
-     * @param {number} n The number of times the function must be called before
-     *  `func` is executed.
+     * _.pluck(_.where(users, { 'age': 36, 'active': false }), 'user');
+     * // => ['barney']
+     *
+     * _.pluck(_.where(users, { 'pets': ['dino'] }), 'user');
+     * // => ['fred']
+     */
+    function where(collection, source) {
+      return filter(collection, baseMatches(source));
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Gets the number of milliseconds that have elapsed since the Unix epoch
+     * (1 January 1970 00:00:00 UTC).
+     *
+     * @static
+     * @memberOf _
+     * @category Date
+     * @example
+     *
+     * _.defer(function(stamp) {
+     *   console.log(_.now() - stamp);
+     * }, _.now());
+     * // => logs the number of milliseconds it took for the deferred function to be invoked
+     */
+    var now = nativeNow || function() {
+      return new Date().getTime();
+    };
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * The opposite of `_.before`; this method creates a function that invokes
+     * `func` once it's called `n` or more times.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {number} n The number of calls before `func` is invoked.
      * @param {Function} func The function to restrict.
      * @returns {Function} Returns the new restricted function.
      * @example
@@ -5127,18 +7282,25 @@
      * var saves = ['profile', 'settings'];
      *
      * var done = _.after(saves.length, function() {
-     *   console.log('Done saving!');
+     *   console.log('done saving!');
      * });
      *
      * _.forEach(saves, function(type) {
      *   asyncSave({ 'type': type, 'complete': done });
      * });
-     * // => logs 'Done saving!', after all saves have completed
+     * // => logs 'done saving!' after the two async saves have completed
      */
     function after(n, func) {
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
+      if (typeof func != 'function') {
+        if (typeof n == 'function') {
+          var temp = n;
+          n = func;
+          func = temp;
+        } else {
+          throw new TypeError(FUNC_ERROR_TEXT);
+        }
+      }
+      n = nativeIsFinite(n = +n) ? n : 0;
       return function() {
         if (--n < 1) {
           return func.apply(this, arguments);
@@ -5147,230 +7309,348 @@
     }
 
     /**
-     * Creates a function that, when called, invokes `func` with the `this`
-     * binding of `thisArg` and prepends any additional `bind` arguments to those
-     * provided to the bound function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * Creates a function that accepts up to `n` arguments ignoring any
+     * additional arguments.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to cap arguments for.
+     * @param {number} [n=func.length] The arity cap.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * _.map(['6', '8', '10'], _.ary(parseInt, 1));
+     * // => [6, 8, 10]
+     */
+    function ary(func, n, guard) {
+      if (guard && isIterateeCall(func, n, guard)) {
+        n = undefined;
+      }
+      n = (func && n == null) ? func.length : nativeMax(+n || 0, 0);
+      return createWrapper(func, ARY_FLAG, undefined, undefined, undefined, undefined, n);
+    }
+
+    /**
+     * Creates a function that invokes `func`, with the `this` binding and arguments
+     * of the created function, while it's called less than `n` times. Subsequent
+     * calls to the created function return the result of the last `func` invocation.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {number} n The number of calls at which `func` is no longer invoked.
+     * @param {Function} func The function to restrict.
+     * @returns {Function} Returns the new restricted function.
+     * @example
+     *
+     * jQuery('#add').on('click', _.before(5, addContactToList));
+     * // => allows adding up to 4 contacts to the list
+     */
+    function before(n, func) {
+      var result;
+      if (typeof func != 'function') {
+        if (typeof n == 'function') {
+          var temp = n;
+          n = func;
+          func = temp;
+        } else {
+          throw new TypeError(FUNC_ERROR_TEXT);
+        }
+      }
+      return function() {
+        if (--n > 0) {
+          result = func.apply(this, arguments);
+        }
+        if (n <= 1) {
+          func = undefined;
+        }
+        return result;
+      };
+    }
+
+    /**
+     * Creates a function that invokes `func` with the `this` binding of `thisArg`
+     * and prepends any additional `_.bind` arguments to those provided to the
+     * bound function.
+     *
+     * The `_.bind.placeholder` value, which defaults to `_` in monolithic builds,
+     * may be used as a placeholder for partially applied arguments.
+     *
+     * **Note:** Unlike native `Function#bind` this method does not set the "length"
+     * property of bound functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to bind.
-     * @param {*} [thisArg] The `this` binding of `func`.
-     * @param {...*} [arg] Arguments to be partially applied.
+     * @param {*} thisArg The `this` binding of `func`.
+     * @param {...*} [partials] The arguments to be partially applied.
      * @returns {Function} Returns the new bound function.
      * @example
      *
-     * var func = function(greeting) {
-     *   return greeting + ' ' + this.name;
+     * var greet = function(greeting, punctuation) {
+     *   return greeting + ' ' + this.user + punctuation;
      * };
      *
-     * func = _.bind(func, { 'name': 'fred' }, 'hi');
-     * func();
-     * // => 'hi fred'
-     */
-    function bind(func, thisArg) {
-      return arguments.length > 2
-        ? createWrapper(func, 17, slice(arguments, 2), null, thisArg)
-        : createWrapper(func, 1, null, null, thisArg);
-    }
+     * var object = { 'user': 'fred' };
+     *
+     * var bound = _.bind(greet, object, 'hi');
+     * bound('!');
+     * // => 'hi fred!'
+     *
+     * // using placeholders
+     * var bound = _.bind(greet, object, _, '!');
+     * bound('hi');
+     * // => 'hi fred!'
+     */
+    var bind = restParam(function(func, thisArg, partials) {
+      var bitmask = BIND_FLAG;
+      if (partials.length) {
+        var holders = replaceHolders(partials, bind.placeholder);
+        bitmask |= PARTIAL_FLAG;
+      }
+      return createWrapper(func, bitmask, thisArg, partials, holders);
+    });
 
     /**
      * Binds methods of an object to the object itself, overwriting the existing
      * method. Method names may be specified as individual arguments or as arrays
-     * of method names. If no method names are provided all the function properties
-     * of `object` will be bound.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * of method names. If no method names are provided all enumerable function
+     * properties, own and inherited, of `object` are bound.
+     *
+     * **Note:** This method does not set the "length" property of bound functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Object} object The object to bind and assign the bound methods to.
-     * @param {...string} [methodName] The object method names to
-     *  bind, specified as individual method names or arrays of method names.
+     * @param {...(string|string[])} [methodNames] The object method names to bind,
+     *  specified as individual method names or arrays of method names.
      * @returns {Object} Returns `object`.
      * @example
      *
      * var view = {
      *   'label': 'docs',
-     *   'onClick': function() { console.log('clicked ' + this.label); }
+     *   'onClick': function() {
+     *     console.log('clicked ' + this.label);
+     *   }
      * };
      *
      * _.bindAll(view);
      * jQuery('#docs').on('click', view.onClick);
-     * // => logs 'clicked docs', when the button is clicked
-     */
-    function bindAll(object) {
-      var funcs = arguments.length > 1 ? baseFlatten(arguments, true, false, 1) : functions(object),
-          index = -1,
-          length = funcs.length;
+     * // => logs 'clicked docs' when the element is clicked
+     */
+    var bindAll = restParam(function(object, methodNames) {
+      methodNames = methodNames.length ? baseFlatten(methodNames) : functions(object);
+
+      var index = -1,
+          length = methodNames.length;
 
       while (++index < length) {
-        var key = funcs[index];
-        object[key] = createWrapper(object[key], 1, null, null, object);
+        var key = methodNames[index];
+        object[key] = createWrapper(object[key], BIND_FLAG, object);
       }
       return object;
-    }
-
-    /**
-     * Creates a function that, when called, invokes the method at `object[key]`
-     * and prepends any additional `bindKey` arguments to those provided to the bound
-     * function. This method differs from `_.bind` by allowing bound functions to
-     * reference methods that will be redefined or don't yet exist.
-     * See http://michaux.ca/articles/lazy-function-definition-pattern.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+    });
+
+    /**
+     * Creates a function that invokes the method at `object[key]` and prepends
+     * any additional `_.bindKey` arguments to those provided to the bound function.
+     *
+     * This method differs from `_.bind` by allowing bound functions to reference
+     * methods that may be redefined or don't yet exist.
+     * See [Peter Michaux's article](http://peter.michaux.ca/articles/lazy-function-definition-pattern)
+     * for more details.
+     *
+     * The `_.bindKey.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for partially applied arguments.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Object} object The object the method belongs to.
      * @param {string} key The key of the method.
-     * @param {...*} [arg] Arguments to be partially applied.
+     * @param {...*} [partials] The arguments to be partially applied.
      * @returns {Function} Returns the new bound function.
      * @example
      *
      * var object = {
-     *   'name': 'fred',
-     *   'greet': function(greeting) {
-     *     return greeting + ' ' + this.name;
+     *   'user': 'fred',
+     *   'greet': function(greeting, punctuation) {
+     *     return greeting + ' ' + this.user + punctuation;
      *   }
      * };
      *
-     * var func = _.bindKey(object, 'greet', 'hi');
-     * func();
-     * // => 'hi fred'
-     *
-     * object.greet = function(greeting) {
-     *   return greeting + 'ya ' + this.name + '!';
-     * };
-     *
-     * func();
-     * // => 'hiya fred!'
-     */
-    function bindKey(object, key) {
-      return arguments.length > 2
-        ? createWrapper(key, 19, slice(arguments, 2), null, object)
-        : createWrapper(key, 3, null, null, object);
-    }
-
-    /**
-     * Creates a function that is the composition of the provided functions,
-     * where each function consumes the return value of the function that follows.
-     * For example, composing the functions `f()`, `g()`, and `h()` produces `f(g(h()))`.
-     * Each function is executed with the `this` binding of the composed function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
-     * @param {...Function} [func] Functions to compose.
-     * @returns {Function} Returns the new composed function.
-     * @example
-     *
-     * var realNameMap = {
-     *   'pebbles': 'penelope'
-     * };
-     *
-     * var format = function(name) {
-     *   name = realNameMap[name.toLowerCase()] || name;
-     *   return name.charAt(0).toUpperCase() + name.slice(1).toLowerCase();
+     * var bound = _.bindKey(object, 'greet', 'hi');
+     * bound('!');
+     * // => 'hi fred!'
+     *
+     * object.greet = function(greeting, punctuation) {
+     *   return greeting + 'ya ' + this.user + punctuation;
      * };
      *
-     * var greet = function(formatted) {
-     *   return 'Hiya ' + formatted + '!';
-     * };
-     *
-     * var welcome = _.compose(greet, format);
-     * welcome('pebbles');
-     * // => 'Hiya Penelope!'
-     */
-    function compose() {
-      var funcs = arguments,
-          length = funcs.length;
-
-      while (length--) {
-        if (!isFunction(funcs[length])) {
-          throw new TypeError;
-        }
-      }
-      return function() {
-        var args = arguments,
-            length = funcs.length;
-
-        while (length--) {
-          args = [funcs[length].apply(this, args)];
-        }
-        return args[0];
-      };
-    }
-
-    /**
-     * Creates a function which accepts one or more arguments of `func` that when
-     * invoked either executes `func` returning its result, if all `func` arguments
+     * bound('!');
+     * // => 'hiya fred!'
+     *
+     * // using placeholders
+     * var bound = _.bindKey(object, 'greet', _, '!');
+     * bound('hi');
+     * // => 'hiya fred!'
+     */
+    var bindKey = restParam(function(object, key, partials) {
+      var bitmask = BIND_FLAG | BIND_KEY_FLAG;
+      if (partials.length) {
+        var holders = replaceHolders(partials, bindKey.placeholder);
+        bitmask |= PARTIAL_FLAG;
+      }
+      return createWrapper(key, bitmask, object, partials, holders);
+    });
+
+    /**
+     * Creates a function that accepts one or more arguments of `func` that when
+     * called either invokes `func` returning its result, if all `func` arguments
      * have been provided, or returns a function that accepts one or more of the
-     * remaining `func` arguments, and so on. The arity of `func` can be specified
+     * remaining `func` arguments, and so on. The arity of `func` may be specified
      * if `func.length` is not sufficient.
      *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * The `_.curry.placeholder` value, which defaults to `_` in monolithic builds,
+     * may be used as a placeholder for provided arguments.
+     *
+     * **Note:** This method does not set the "length" property of curried functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to curry.
      * @param {number} [arity=func.length] The arity of `func`.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
      * @returns {Function} Returns the new curried function.
      * @example
      *
-     * var curried = _.curry(function(a, b, c) {
-     *   console.log(a + b + c);
-     * });
+     * var abc = function(a, b, c) {
+     *   return [a, b, c];
+     * };
+     *
+     * var curried = _.curry(abc);
      *
      * curried(1)(2)(3);
-     * // => 6
+     * // => [1, 2, 3]
      *
      * curried(1, 2)(3);
-     * // => 6
+     * // => [1, 2, 3]
      *
      * curried(1, 2, 3);
-     * // => 6
-     */
-    function curry(func, arity) {
-      arity = typeof arity == 'number' ? arity : (+arity || func.length);
-      return createWrapper(func, 4, null, null, null, arity);
-    }
-
-    /**
-     * Creates a function that will delay the execution of `func` until after
-     * `wait` milliseconds have elapsed since the last time it was invoked.
-     * Provide an options object to indicate that `func` should be invoked on
-     * the leading and/or trailing edge of the `wait` timeout. Subsequent calls
-     * to the debounced function will return the result of the last `func` call.
-     *
-     * Note: If `leading` and `trailing` options are `true` `func` will be called
+     * // => [1, 2, 3]
+     *
+     * // using placeholders
+     * curried(1)(_, 3)(2);
+     * // => [1, 2, 3]
+     */
+    var curry = createCurry(CURRY_FLAG);
+
+    /**
+     * This method is like `_.curry` except that arguments are applied to `func`
+     * in the manner of `_.partialRight` instead of `_.partial`.
+     *
+     * The `_.curryRight.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for provided arguments.
+     *
+     * **Note:** This method does not set the "length" property of curried functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to curry.
+     * @param {number} [arity=func.length] The arity of `func`.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Function} Returns the new curried function.
+     * @example
+     *
+     * var abc = function(a, b, c) {
+     *   return [a, b, c];
+     * };
+     *
+     * var curried = _.curryRight(abc);
+     *
+     * curried(3)(2)(1);
+     * // => [1, 2, 3]
+     *
+     * curried(2, 3)(1);
+     * // => [1, 2, 3]
+     *
+     * curried(1, 2, 3);
+     * // => [1, 2, 3]
+     *
+     * // using placeholders
+     * curried(3)(1, _)(2);
+     * // => [1, 2, 3]
+     */
+    var curryRight = createCurry(CURRY_RIGHT_FLAG);
+
+    /**
+     * Creates a debounced function that delays invoking `func` until after `wait`
+     * milliseconds have elapsed since the last time the debounced function was
+     * invoked. The debounced function comes with a `cancel` method to cancel
+     * delayed invocations. Provide an options object to indicate that `func`
+     * should be invoked on the leading and/or trailing edge of the `wait` timeout.
+     * Subsequent calls to the debounced function return the result of the last
+     * `func` invocation.
+     *
+     * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
      * on the trailing edge of the timeout only if the the debounced function is
      * invoked more than once during the `wait` timeout.
      *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
+     * for details over the differences between `_.debounce` and `_.throttle`.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to debounce.
-     * @param {number} wait The number of milliseconds to delay.
+     * @param {number} [wait=0] The number of milliseconds to delay.
      * @param {Object} [options] The options object.
-     * @param {boolean} [options.leading=false] Specify execution on the leading edge of the timeout.
-     * @param {number} [options.maxWait] The maximum time `func` is allowed to be delayed before it's called.
-     * @param {boolean} [options.trailing=true] Specify execution on the trailing edge of the timeout.
+     * @param {boolean} [options.leading=false] Specify invoking on the leading
+     *  edge of the timeout.
+     * @param {number} [options.maxWait] The maximum time `func` is allowed to be
+     *  delayed before it's invoked.
+     * @param {boolean} [options.trailing=true] Specify invoking on the trailing
+     *  edge of the timeout.
      * @returns {Function} Returns the new debounced function.
      * @example
      *
      * // avoid costly calculations while the window size is in flux
-     * var lazyLayout = _.debounce(calculateLayout, 150);
-     * jQuery(window).on('resize', lazyLayout);
-     *
-     * // execute `sendMail` when the click event is fired, debouncing subsequent calls
+     * jQuery(window).on('resize', _.debounce(calculateLayout, 150));
+     *
+     * // invoke `sendMail` when the click event is fired, debouncing subsequent calls
      * jQuery('#postbox').on('click', _.debounce(sendMail, 300, {
      *   'leading': true,
      *   'trailing': false
-     * });
-     *
-     * // ensure `batchLog` is executed once after 1 second of debounced calls
+     * }));
+     *
+     * // ensure `batchLog` is invoked once after 1 second of debounced calls
      * var source = new EventSource('/stream');
-     * source.addEventListener('message', _.debounce(batchLog, 250, {
+     * jQuery(source).on('message', _.debounce(batchLog, 250, {
      *   'maxWait': 1000
-     * }, false);
+     * }));
+     *
+     * // cancel a debounced call
+     * var todoChanges = _.debounce(batchLog, 1000);
+     * Object.observe(models.todo, todoChanges);
+     *
+     * Object.observe(models, function(changes) {
+     *   if (_.find(changes, { 'user': 'todo', 'type': 'delete'})) {
+     *     todoChanges.cancel();
+     *   }
+     * }, ['delete']);
+     *
+     * // ...at some point `models.todo` is changed
+     * models.todo.completed = true;
+     *
+     * // ...before 1 second has passed `models.todo` is deleted
+     * // which cancels the debounced `todoChanges` call
+     * delete models.todo;
      */
     function debounce(func, wait, options) {
       var args,
@@ -5384,53 +7664,58 @@
           maxWait = false,
           trailing = true;
 
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      wait = nativeMax(0, wait) || 0;
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      wait = wait < 0 ? 0 : (+wait || 0);
       if (options === true) {
         var leading = true;
         trailing = false;
       } else if (isObject(options)) {
-        leading = options.leading;
-        maxWait = 'maxWait' in options && (nativeMax(wait, options.maxWait) || 0);
-        trailing = 'trailing' in options ? options.trailing : trailing;
-      }
-      var delayed = function() {
-        var remaining = wait - (now() - stamp);
-        if (remaining <= 0) {
-          if (maxTimeoutId) {
-            clearTimeout(maxTimeoutId);
-          }
-          var isCalled = trailingCall;
-          maxTimeoutId = timeoutId = trailingCall = undefined;
-          if (isCalled) {
-            lastCalled = now();
-            result = func.apply(thisArg, args);
-            if (!timeoutId && !maxTimeoutId) {
-              args = thisArg = null;
-            }
-          }
-        } else {
-          timeoutId = setTimeout(delayed, remaining);
-        }
-      };
-
-      var maxDelayed = function() {
+        leading = !!options.leading;
+        maxWait = 'maxWait' in options && nativeMax(+options.maxWait || 0, wait);
+        trailing = 'trailing' in options ? !!options.trailing : trailing;
+      }
+
+      function cancel() {
         if (timeoutId) {
           clearTimeout(timeoutId);
         }
+        if (maxTimeoutId) {
+          clearTimeout(maxTimeoutId);
+        }
+        lastCalled = 0;
         maxTimeoutId = timeoutId = trailingCall = undefined;
-        if (trailing || (maxWait !== wait)) {
+      }
+
+      function complete(isCalled, id) {
+        if (id) {
+          clearTimeout(id);
+        }
+        maxTimeoutId = timeoutId = trailingCall = undefined;
+        if (isCalled) {
           lastCalled = now();
           result = func.apply(thisArg, args);
           if (!timeoutId && !maxTimeoutId) {
-            args = thisArg = null;
+            args = thisArg = undefined;
           }
         }
-      };
-
-      return function() {
+      }
+
+      function delayed() {
+        var remaining = wait - (now() - stamp);
+        if (remaining <= 0 || remaining > wait) {
+          complete(trailingCall, maxTimeoutId);
+        } else {
+          timeoutId = setTimeout(delayed, remaining);
+        }
+      }
+
+      function maxDelayed() {
+        complete(trailing, timeoutId);
+      }
+
+      function debounced() {
         args = arguments;
         stamp = now();
         thisArg = this;
@@ -5443,7 +7728,7 @@
             lastCalled = stamp;
           }
           var remaining = maxWait - (stamp - lastCalled),
-              isCalled = remaining <= 0;
+              isCalled = remaining <= 0 || remaining > maxWait;
 
           if (isCalled) {
             if (maxTimeoutId) {
@@ -5467,120 +7752,254 @@
           result = func.apply(thisArg, args);
         }
         if (isCalled && !timeoutId && !maxTimeoutId) {
-          args = thisArg = null;
+          args = thisArg = undefined;
         }
         return result;
-      };
-    }
-
-    /**
-     * Defers executing the `func` function until the current call stack has cleared.
-     * Additional arguments will be provided to `func` when it is invoked.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+      }
+      debounced.cancel = cancel;
+      return debounced;
+    }
+
+    /**
+     * Defers invoking the `func` until the current call stack has cleared. Any
+     * additional arguments are provided to `func` when it's invoked.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to defer.
-     * @param {...*} [arg] Arguments to invoke the function with.
+     * @param {...*} [args] The arguments to invoke the function with.
      * @returns {number} Returns the timer id.
      * @example
      *
-     * _.defer(function(text) { console.log(text); }, 'deferred');
+     * _.defer(function(text) {
+     *   console.log(text);
+     * }, 'deferred');
      * // logs 'deferred' after one or more milliseconds
      */
-    function defer(func) {
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      var args = slice(arguments, 1);
-      return setTimeout(function() { func.apply(undefined, args); }, 1);
-    }
-
-    /**
-     * Executes the `func` function after `wait` milliseconds. Additional arguments
-     * will be provided to `func` when it is invoked.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+    var defer = restParam(function(func, args) {
+      return baseDelay(func, 1, args);
+    });
+
+    /**
+     * Invokes `func` after `wait` milliseconds. Any additional arguments are
+     * provided to `func` when it's invoked.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to delay.
-     * @param {number} wait The number of milliseconds to delay execution.
-     * @param {...*} [arg] Arguments to invoke the function with.
+     * @param {number} wait The number of milliseconds to delay invocation.
+     * @param {...*} [args] The arguments to invoke the function with.
      * @returns {number} Returns the timer id.
      * @example
      *
-     * _.delay(function(text) { console.log(text); }, 1000, 'later');
+     * _.delay(function(text) {
+     *   console.log(text);
+     * }, 1000, 'later');
      * // => logs 'later' after one second
      */
-    function delay(func, wait) {
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      var args = slice(arguments, 2);
-      return setTimeout(function() { func.apply(undefined, args); }, wait);
-    }
+    var delay = restParam(function(func, wait, args) {
+      return baseDelay(func, wait, args);
+    });
+
+    /**
+     * Creates a function that returns the result of invoking the provided
+     * functions with the `this` binding of the created function, where each
+     * successive invocation is supplied the return value of the previous.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {...Function} [funcs] Functions to invoke.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * function square(n) {
+     *   return n * n;
+     * }
+     *
+     * var addSquare = _.flow(_.add, square);
+     * addSquare(1, 2);
+     * // => 9
+     */
+    var flow = createFlow();
+
+    /**
+     * This method is like `_.flow` except that it creates a function that
+     * invokes the provided functions from right to left.
+     *
+     * @static
+     * @memberOf _
+     * @alias backflow, compose
+     * @category Function
+     * @param {...Function} [funcs] Functions to invoke.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * function square(n) {
+     *   return n * n;
+     * }
+     *
+     * var addSquare = _.flowRight(square, _.add);
+     * addSquare(1, 2);
+     * // => 9
+     */
+    var flowRight = createFlow(true);
 
     /**
      * Creates a function that memoizes the result of `func`. If `resolver` is
-     * provided it will be used to determine the cache key for storing the result
-     * based on the arguments provided to the memoized function. By default, the
-     * first argument provided to the memoized function is used as the cache key.
-     * The `func` is executed with the `this` binding of the memoized function.
-     * The result cache is exposed as the `cache` property on the memoized function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * provided it determines the cache key for storing the result based on the
+     * arguments provided to the memoized function. By default, the first argument
+     * provided to the memoized function is coerced to a string and used as the
+     * cache key. The `func` is invoked with the `this` binding of the memoized
+     * function.
+     *
+     * **Note:** The cache is exposed as the `cache` property on the memoized
+     * function. Its creation may be customized by replacing the `_.memoize.Cache`
+     * constructor with one whose instances implement the [`Map`](http://ecma-international.org/ecma-262/6.0/#sec-properties-of-the-map-prototype-object)
+     * method interface of `get`, `has`, and `set`.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to have its output memoized.
-     * @param {Function} [resolver] A function used to resolve the cache key.
+     * @param {Function} [resolver] The function to resolve the cache key.
      * @returns {Function} Returns the new memoizing function.
      * @example
      *
-     * var fibonacci = _.memoize(function(n) {
-     *   return n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2);
+     * var upperCase = _.memoize(function(string) {
+     *   return string.toUpperCase();
      * });
      *
-     * fibonacci(9)
-     * // => 34
-     *
-     * var data = {
-     *   'fred': { 'name': 'fred', 'age': 40 },
-     *   'pebbles': { 'name': 'pebbles', 'age': 1 }
-     * };
+     * upperCase('fred');
+     * // => 'FRED'
      *
      * // modifying the result cache
-     * var get = _.memoize(function(name) { return data[name]; }, _.identity);
-     * get('pebbles');
-     * // => { 'name': 'pebbles', 'age': 1 }
-     *
-     * get.cache.pebbles.name = 'penelope';
-     * get('pebbles');
-     * // => { 'name': 'penelope', 'age': 1 }
+     * upperCase.cache.set('fred', 'BARNEY');
+     * upperCase('fred');
+     * // => 'BARNEY'
+     *
+     * // replacing `_.memoize.Cache`
+     * var object = { 'user': 'fred' };
+     * var other = { 'user': 'barney' };
+     * var identity = _.memoize(_.identity);
+     *
+     * identity(object);
+     * // => { 'user': 'fred' }
+     * identity(other);
+     * // => { 'user': 'fred' }
+     *
+     * _.memoize.Cache = WeakMap;
+     * var identity = _.memoize(_.identity);
+     *
+     * identity(object);
+     * // => { 'user': 'fred' }
+     * identity(other);
+     * // => { 'user': 'barney' }
      */
     function memoize(func, resolver) {
-      if (!isFunction(func)) {
-        throw new TypeError;
+      if (typeof func != 'function' || (resolver && typeof resolver != 'function')) {
+        throw new TypeError(FUNC_ERROR_TEXT);
       }
       var memoized = function() {
-        var cache = memoized.cache,
-            key = resolver ? resolver.apply(this, arguments) : keyPrefix + arguments[0];
-
-        return hasOwnProperty.call(cache, key)
-          ? cache[key]
-          : (cache[key] = func.apply(this, arguments));
-      }
-      memoized.cache = {};
+        var args = arguments,
+            key = resolver ? resolver.apply(this, args) : args[0],
+            cache = memoized.cache;
+
+        if (cache.has(key)) {
+          return cache.get(key);
+        }
+        var result = func.apply(this, args);
+        memoized.cache = cache.set(key, result);
+        return result;
+      };
+      memoized.cache = new memoize.Cache;
       return memoized;
     }
 
     /**
-     * Creates a function that is restricted to execute `func` once. Repeat calls to
-     * the function will return the value of the first call. The `func` is executed
-     * with the `this` binding of the created function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * Creates a function that runs each argument through a corresponding
+     * transform function.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to wrap.
+     * @param {...(Function|Function[])} [transforms] The functions to transform
+     * arguments, specified as individual functions or arrays of functions.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * function doubled(n) {
+     *   return n * 2;
+     * }
+     *
+     * function square(n) {
+     *   return n * n;
+     * }
+     *
+     * var modded = _.modArgs(function(x, y) {
+     *   return [x, y];
+     * }, square, doubled);
+     *
+     * modded(1, 2);
+     * // => [1, 4]
+     *
+     * modded(5, 10);
+     * // => [25, 20]
+     */
+    var modArgs = restParam(function(func, transforms) {
+      transforms = baseFlatten(transforms);
+      if (typeof func != 'function' || !arrayEvery(transforms, baseIsFunction)) {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      var length = transforms.length;
+      return restParam(function(args) {
+        var index = nativeMin(args.length, length);
+        while (index--) {
+          args[index] = transforms[index](args[index]);
+        }
+        return func.apply(this, args);
+      });
+    });
+
+    /**
+     * Creates a function that negates the result of the predicate `func`. The
+     * `func` predicate is invoked with the `this` binding and arguments of the
+     * created function.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} predicate The predicate to negate.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * function isEven(n) {
+     *   return n % 2 == 0;
+     * }
+     *
+     * _.filter([1, 2, 3, 4, 5, 6], _.negate(isEven));
+     * // => [1, 3, 5]
+     */
+    function negate(predicate) {
+      if (typeof predicate != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      return function() {
+        return !predicate.apply(this, arguments);
+      };
+    }
+
+    /**
+     * Creates a function that is restricted to invoking `func` once. Repeat calls
+     * to the function return the value of the first call. The `func` is invoked
+     * with the `this` binding and arguments of the created function.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to restrict.
      * @returns {Function} Returns the new restricted function.
      * @example
@@ -5588,141 +8007,266 @@
      * var initialize = _.once(createApplication);
      * initialize();
      * initialize();
-     * // `initialize` executes `createApplication` once
+     * // `initialize` invokes `createApplication` once
      */
     function once(func) {
-      var ran,
-          result;
-
-      if (!isFunction(func)) {
-        throw new TypeError;
-      }
-      return function() {
-        if (ran) {
-          return result;
-        }
-        ran = true;
-        result = func.apply(this, arguments);
-
-        // clear the `func` variable so the function may be garbage collected
-        func = null;
-        return result;
-      };
-    }
-
-    /**
-     * Creates a function that, when called, invokes `func` with any additional
-     * `partial` arguments prepended to those provided to the new function. This
-     * method is similar to `_.bind` except it does **not** alter the `this` binding.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+      return before(2, func);
+    }
+
+    /**
+     * Creates a function that invokes `func` with `partial` arguments prepended
+     * to those provided to the new function. This method is like `_.bind` except
+     * it does **not** alter the `this` binding.
+     *
+     * The `_.partial.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for partially applied arguments.
+     *
+     * **Note:** This method does not set the "length" property of partially
+     * applied functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to partially apply arguments to.
-     * @param {...*} [arg] Arguments to be partially applied.
+     * @param {...*} [partials] The arguments to be partially applied.
      * @returns {Function} Returns the new partially applied function.
      * @example
      *
-     * var greet = function(greeting, name) { return greeting + ' ' + name; };
-     * var hi = _.partial(greet, 'hi');
-     * hi('fred');
+     * var greet = function(greeting, name) {
+     *   return greeting + ' ' + name;
+     * };
+     *
+     * var sayHelloTo = _.partial(greet, 'hello');
+     * sayHelloTo('fred');
+     * // => 'hello fred'
+     *
+     * // using placeholders
+     * var greetFred = _.partial(greet, _, 'fred');
+     * greetFred('hi');
+     * // => 'hi fred'
+     */
+    var partial = createPartial(PARTIAL_FLAG);
+
+    /**
+     * This method is like `_.partial` except that partially applied arguments
+     * are appended to those provided to the new function.
+     *
+     * The `_.partialRight.placeholder` value, which defaults to `_` in monolithic
+     * builds, may be used as a placeholder for partially applied arguments.
+     *
+     * **Note:** This method does not set the "length" property of partially
+     * applied functions.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to partially apply arguments to.
+     * @param {...*} [partials] The arguments to be partially applied.
+     * @returns {Function} Returns the new partially applied function.
+     * @example
+     *
+     * var greet = function(greeting, name) {
+     *   return greeting + ' ' + name;
+     * };
+     *
+     * var greetFred = _.partialRight(greet, 'fred');
+     * greetFred('hi');
      * // => 'hi fred'
-     */
-    function partial(func) {
-      return createWrapper(func, 16, slice(arguments, 1));
-    }
-
-    /**
-     * This method is like `_.partial` except that `partial` arguments are
-     * appended to those provided to the new function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
-     * @param {Function} func The function to partially apply arguments to.
-     * @param {...*} [arg] Arguments to be partially applied.
-     * @returns {Function} Returns the new partially applied function.
-     * @example
-     *
-     * var defaultsDeep = _.partialRight(_.merge, _.defaults);
-     *
-     * var options = {
-     *   'variable': 'data',
-     *   'imports': { 'jq': $ }
-     * };
-     *
-     * defaultsDeep(options, _.templateSettings);
-     *
-     * options.variable
-     * // => 'data'
-     *
-     * options.imports
-     * // => { '_': _, 'jq': $ }
-     */
-    function partialRight(func) {
-      return createWrapper(func, 32, null, slice(arguments, 1));
-    }
-
-    /**
-     * Creates a function that, when executed, will only call the `func` function
-     * at most once per every `wait` milliseconds. Provide an options object to
-     * indicate that `func` should be invoked on the leading and/or trailing edge
-     * of the `wait` timeout. Subsequent calls to the throttled function will
-     * return the result of the last `func` call.
-     *
-     * Note: If `leading` and `trailing` options are `true` `func` will be called
+     *
+     * // using placeholders
+     * var sayHelloTo = _.partialRight(greet, 'hello', _);
+     * sayHelloTo('fred');
+     * // => 'hello fred'
+     */
+    var partialRight = createPartial(PARTIAL_RIGHT_FLAG);
+
+    /**
+     * Creates a function that invokes `func` with arguments arranged according
+     * to the specified indexes where the argument value at the first index is
+     * provided as the first argument, the argument value at the second index is
+     * provided as the second argument, and so on.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to rearrange arguments for.
+     * @param {...(number|number[])} indexes The arranged argument indexes,
+     *  specified as individual indexes or arrays of indexes.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var rearged = _.rearg(function(a, b, c) {
+     *   return [a, b, c];
+     * }, 2, 0, 1);
+     *
+     * rearged('b', 'c', 'a')
+     * // => ['a', 'b', 'c']
+     *
+     * var map = _.rearg(_.map, [1, 0]);
+     * map(function(n) {
+     *   return n * 3;
+     * }, [1, 2, 3]);
+     * // => [3, 6, 9]
+     */
+    var rearg = restParam(function(func, indexes) {
+      return createWrapper(func, REARG_FLAG, undefined, undefined, undefined, baseFlatten(indexes));
+    });
+
+    /**
+     * Creates a function that invokes `func` with the `this` binding of the
+     * created function and arguments from `start` and beyond provided as an array.
+     *
+     * **Note:** This method is based on the [rest parameter](https://developer.mozilla.org/Web/JavaScript/Reference/Functions/rest_parameters).
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to apply a rest parameter to.
+     * @param {number} [start=func.length-1] The start position of the rest parameter.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var say = _.restParam(function(what, names) {
+     *   return what + ' ' + _.initial(names).join(', ') +
+     *     (_.size(names) > 1 ? ', & ' : '') + _.last(names);
+     * });
+     *
+     * say('hello', 'fred', 'barney', 'pebbles');
+     * // => 'hello fred, barney, & pebbles'
+     */
+    function restParam(func, start) {
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      start = nativeMax(start === undefined ? (func.length - 1) : (+start || 0), 0);
+      return function() {
+        var args = arguments,
+            index = -1,
+            length = nativeMax(args.length - start, 0),
+            rest = Array(length);
+
+        while (++index < length) {
+          rest[index] = args[start + index];
+        }
+        switch (start) {
+          case 0: return func.call(this, rest);
+          case 1: return func.call(this, args[0], rest);
+          case 2: return func.call(this, args[0], args[1], rest);
+        }
+        var otherArgs = Array(start + 1);
+        index = -1;
+        while (++index < start) {
+          otherArgs[index] = args[index];
+        }
+        otherArgs[start] = rest;
+        return func.apply(this, otherArgs);
+      };
+    }
+
+    /**
+     * Creates a function that invokes `func` with the `this` binding of the created
+     * function and an array of arguments much like [`Function#apply`](https://es5.github.io/#x15.3.4.3).
+     *
+     * **Note:** This method is based on the [spread operator](https://developer.mozilla.org/Web/JavaScript/Reference/Operators/Spread_operator).
+     *
+     * @static
+     * @memberOf _
+     * @category Function
+     * @param {Function} func The function to spread arguments over.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var say = _.spread(function(who, what) {
+     *   return who + ' says ' + what;
+     * });
+     *
+     * say(['fred', 'hello']);
+     * // => 'fred says hello'
+     *
+     * // with a Promise
+     * var numbers = Promise.all([
+     *   Promise.resolve(40),
+     *   Promise.resolve(36)
+     * ]);
+     *
+     * numbers.then(_.spread(function(x, y) {
+     *   return x + y;
+     * }));
+     * // => a Promise of 76
+     */
+    function spread(func) {
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
+      }
+      return function(array) {
+        return func.apply(this, array);
+      };
+    }
+
+    /**
+     * Creates a throttled function that only invokes `func` at most once per
+     * every `wait` milliseconds. The throttled function comes with a `cancel`
+     * method to cancel delayed invocations. Provide an options object to indicate
+     * that `func` should be invoked on the leading and/or trailing edge of the
+     * `wait` timeout. Subsequent calls to the throttled function return the
+     * result of the last `func` call.
+     *
+     * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
      * on the trailing edge of the timeout only if the the throttled function is
      * invoked more than once during the `wait` timeout.
      *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
+     * for details over the differences between `_.throttle` and `_.debounce`.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {Function} func The function to throttle.
-     * @param {number} wait The number of milliseconds to throttle executions to.
+     * @param {number} [wait=0] The number of milliseconds to throttle invocations to.
      * @param {Object} [options] The options object.
-     * @param {boolean} [options.leading=true] Specify execution on the leading edge of the timeout.
-     * @param {boolean} [options.trailing=true] Specify execution on the trailing edge of the timeout.
+     * @param {boolean} [options.leading=true] Specify invoking on the leading
+     *  edge of the timeout.
+     * @param {boolean} [options.trailing=true] Specify invoking on the trailing
+     *  edge of the timeout.
      * @returns {Function} Returns the new throttled function.
      * @example
      *
      * // avoid excessively updating the position while scrolling
-     * var throttled = _.throttle(updatePosition, 100);
-     * jQuery(window).on('scroll', throttled);
-     *
-     * // execute `renewToken` when the click event is fired, but not more than once every 5 minutes
+     * jQuery(window).on('scroll', _.throttle(updatePosition, 100));
+     *
+     * // invoke `renewToken` when the click event is fired, but not more than once every 5 minutes
      * jQuery('.interactive').on('click', _.throttle(renewToken, 300000, {
      *   'trailing': false
      * }));
+     *
+     * // cancel a trailing throttled call
+     * jQuery(window).on('popstate', throttled.cancel);
      */
     function throttle(func, wait, options) {
       var leading = true,
           trailing = true;
 
-      if (!isFunction(func)) {
-        throw new TypeError;
+      if (typeof func != 'function') {
+        throw new TypeError(FUNC_ERROR_TEXT);
       }
       if (options === false) {
         leading = false;
       } else if (isObject(options)) {
-        leading = 'leading' in options ? options.leading : leading;
-        trailing = 'trailing' in options ? options.trailing : trailing;
-      }
-      debounceOptions.leading = leading;
-      debounceOptions.maxWait = wait;
-      debounceOptions.trailing = trailing;
-
-      return debounce(func, wait, debounceOptions);
+        leading = 'leading' in options ? !!options.leading : leading;
+        trailing = 'trailing' in options ? !!options.trailing : trailing;
+      }
+      return debounce(func, wait, { 'leading': leading, 'maxWait': +wait, 'trailing': trailing });
     }
 
     /**
      * Creates a function that provides `value` to the wrapper function as its
-     * first argument. Additional arguments provided to the function are appended
-     * to those provided to the wrapper function. The wrapper is executed with
-     * the `this` binding of the created function.
-     *
-     * @static
-     * @memberOf _
-     * @category Functions
+     * first argument. Any additional arguments provided to the function are
+     * appended to those provided to the wrapper function. The wrapper is invoked
+     * with the `this` binding of the created function.
+     *
+     * @static
+     * @memberOf _
+     * @category Function
      * @param {*} value The value to wrap.
      * @param {Function} wrapper The wrapper function.
      * @returns {Function} Returns the new function.
@@ -5732,327 +8276,1879 @@
      *   return '<p>' + func(text) + '</p>';
      * });
      *
-     * p('Fred, Wilma, & Pebbles');
-     * // => '<p>Fred, Wilma, &amp; Pebbles</p>'
+     * p('fred, barney, & pebbles');
+     * // => '<p>fred, barney, &amp; pebbles</p>'
      */
     function wrap(value, wrapper) {
-      return createWrapper(wrapper, 16, [value]);
-    }
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates a function that returns `value`.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {*} value The value to return from the new function.
-     * @returns {Function} Returns the new function.
-     * @example
-     *
-     * var object = { 'name': 'fred' };
-     * var getter = _.constant(object);
-     * getter() === object;
+      wrapper = wrapper == null ? identity : wrapper;
+      return createWrapper(wrapper, PARTIAL_FLAG, undefined, [value], []);
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Creates a clone of `value`. If `isDeep` is `true` nested objects are cloned,
+     * otherwise they are assigned by reference. If `customizer` is provided it's
+     * invoked to produce the cloned values. If `customizer` returns `undefined`
+     * cloning is handled by the method instead. The `customizer` is bound to
+     * `thisArg` and invoked with up to three argument; (value [, index|key, object]).
+     *
+     * **Note:** This method is loosely based on the
+     * [structured clone algorithm](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm).
+     * The enumerable properties of `arguments` objects and objects created by
+     * constructors other than `Object` are cloned to plain `Object` objects. An
+     * empty object is returned for uncloneable values such as functions, DOM nodes,
+     * Maps, Sets, and WeakMaps.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to clone.
+     * @param {boolean} [isDeep] Specify a deep clone.
+     * @param {Function} [customizer] The function to customize cloning values.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {*} Returns the cloned value.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney' },
+     *   { 'user': 'fred' }
+     * ];
+     *
+     * var shallow = _.clone(users);
+     * shallow[0] === users[0];
+     * // => true
+     *
+     * var deep = _.clone(users, true);
+     * deep[0] === users[0];
+     * // => false
+     *
+     * // using a customizer callback
+     * var el = _.clone(document.body, function(value) {
+     *   if (_.isElement(value)) {
+     *     return value.cloneNode(false);
+     *   }
+     * });
+     *
+     * el === document.body
+     * // => false
+     * el.nodeName
+     * // => BODY
+     * el.childNodes.length;
+     * // => 0
+     */
+    function clone(value, isDeep, customizer, thisArg) {
+      if (isDeep && typeof isDeep != 'boolean' && isIterateeCall(value, isDeep, customizer)) {
+        isDeep = false;
+      }
+      else if (typeof isDeep == 'function') {
+        thisArg = customizer;
+        customizer = isDeep;
+        isDeep = false;
+      }
+      return typeof customizer == 'function'
+        ? baseClone(value, isDeep, bindCallback(customizer, thisArg, 3))
+        : baseClone(value, isDeep);
+    }
+
+    /**
+     * Creates a deep clone of `value`. If `customizer` is provided it's invoked
+     * to produce the cloned values. If `customizer` returns `undefined` cloning
+     * is handled by the method instead. The `customizer` is bound to `thisArg`
+     * and invoked with up to three argument; (value [, index|key, object]).
+     *
+     * **Note:** This method is loosely based on the
+     * [structured clone algorithm](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm).
+     * The enumerable properties of `arguments` objects and objects created by
+     * constructors other than `Object` are cloned to plain `Object` objects. An
+     * empty object is returned for uncloneable values such as functions, DOM nodes,
+     * Maps, Sets, and WeakMaps.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to deep clone.
+     * @param {Function} [customizer] The function to customize cloning values.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {*} Returns the deep cloned value.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney' },
+     *   { 'user': 'fred' }
+     * ];
+     *
+     * var deep = _.cloneDeep(users);
+     * deep[0] === users[0];
+     * // => false
+     *
+     * // using a customizer callback
+     * var el = _.cloneDeep(document.body, function(value) {
+     *   if (_.isElement(value)) {
+     *     return value.cloneNode(true);
+     *   }
+     * });
+     *
+     * el === document.body
+     * // => false
+     * el.nodeName
+     * // => BODY
+     * el.childNodes.length;
+     * // => 20
+     */
+    function cloneDeep(value, customizer, thisArg) {
+      return typeof customizer == 'function'
+        ? baseClone(value, true, bindCallback(customizer, thisArg, 3))
+        : baseClone(value, true);
+    }
+
+    /**
+     * Checks if `value` is greater than `other`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is greater than `other`, else `false`.
+     * @example
+     *
+     * _.gt(3, 1);
+     * // => true
+     *
+     * _.gt(3, 3);
+     * // => false
+     *
+     * _.gt(1, 3);
+     * // => false
+     */
+    function gt(value, other) {
+      return value > other;
+    }
+
+    /**
+     * Checks if `value` is greater than or equal to `other`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is greater than or equal to `other`, else `false`.
+     * @example
+     *
+     * _.gte(3, 1);
+     * // => true
+     *
+     * _.gte(3, 3);
      * // => true
-     */
-    function constant(value) {
-      return function() {
-        return value;
-      };
-    }
-
-    /**
-     * Produces a callback bound to an optional `thisArg`. If `func` is a property
-     * name the created callback will return the property value for a given element.
-     * If `func` is an object the created callback will return `true` for elements
-     * that contain the equivalent object properties, otherwise it will return `false`.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {*} [func=identity] The value to convert to a callback.
-     * @param {*} [thisArg] The `this` binding of the created callback.
-     * @param {number} [argCount] The number of arguments the callback accepts.
-     * @returns {Function} Returns a callback function.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
-     * ];
-     *
-     * // wrap to create custom callback shorthands
-     * _.createCallback = _.wrap(_.createCallback, function(func, callback, thisArg) {
-     *   var match = /^(.+?)__([gl]t)(.+)$/.exec(callback);
-     *   return !match ? func(callback, thisArg) : function(object) {
-     *     return match[2] == 'gt' ? object[match[1]] > match[3] : object[match[1]] < match[3];
-     *   };
+     *
+     * _.gte(1, 3);
+     * // => false
+     */
+    function gte(value, other) {
+      return value >= other;
+    }
+
+    /**
+     * Checks if `value` is classified as an `arguments` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isArguments(function() { return arguments; }());
+     * // => true
+     *
+     * _.isArguments([1, 2, 3]);
+     * // => false
+     */
+    function isArguments(value) {
+      return isObjectLike(value) && isArrayLike(value) &&
+        hasOwnProperty.call(value, 'callee') && !propertyIsEnumerable.call(value, 'callee');
+    }
+
+    /**
+     * Checks if `value` is classified as an `Array` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isArray([1, 2, 3]);
+     * // => true
+     *
+     * _.isArray(function() { return arguments; }());
+     * // => false
+     */
+    var isArray = nativeIsArray || function(value) {
+      return isObjectLike(value) && isLength(value.length) && objToString.call(value) == arrayTag;
+    };
+
+    /**
+     * Checks if `value` is classified as a boolean primitive or object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isBoolean(false);
+     * // => true
+     *
+     * _.isBoolean(null);
+     * // => false
+     */
+    function isBoolean(value) {
+      return value === true || value === false || (isObjectLike(value) && objToString.call(value) == boolTag);
+    }
+
+    /**
+     * Checks if `value` is classified as a `Date` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isDate(new Date);
+     * // => true
+     *
+     * _.isDate('Mon April 23 2012');
+     * // => false
+     */
+    function isDate(value) {
+      return isObjectLike(value) && objToString.call(value) == dateTag;
+    }
+
+    /**
+     * Checks if `value` is a DOM element.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a DOM element, else `false`.
+     * @example
+     *
+     * _.isElement(document.body);
+     * // => true
+     *
+     * _.isElement('<body>');
+     * // => false
+     */
+    function isElement(value) {
+      return !!value && value.nodeType === 1 && isObjectLike(value) && !isPlainObject(value);
+    }
+
+    /**
+     * Checks if `value` is empty. A value is considered empty unless it's an
+     * `arguments` object, array, string, or jQuery-like collection with a length
+     * greater than `0` or an object with own enumerable properties.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {Array|Object|string} value The value to inspect.
+     * @returns {boolean} Returns `true` if `value` is empty, else `false`.
+     * @example
+     *
+     * _.isEmpty(null);
+     * // => true
+     *
+     * _.isEmpty(true);
+     * // => true
+     *
+     * _.isEmpty(1);
+     * // => true
+     *
+     * _.isEmpty([1, 2, 3]);
+     * // => false
+     *
+     * _.isEmpty({ 'a': 1 });
+     * // => false
+     */
+    function isEmpty(value) {
+      if (value == null) {
+        return true;
+      }
+      if (isArrayLike(value) && (isArray(value) || isString(value) || isArguments(value) ||
+          (isObjectLike(value) && isFunction(value.splice)))) {
+        return !value.length;
+      }
+      return !keys(value).length;
+    }
+
+    /**
+     * Performs a deep comparison between two values to determine if they are
+     * equivalent. If `customizer` is provided it's invoked to compare values.
+     * If `customizer` returns `undefined` comparisons are handled by the method
+     * instead. The `customizer` is bound to `thisArg` and invoked with up to
+     * three arguments: (value, other [, index|key]).
+     *
+     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
+     * numbers, `Object` objects, regexes, and strings. Objects are compared by
+     * their own, not inherited, enumerable properties. Functions and DOM nodes
+     * are **not** supported. Provide a customizer function to extend support
+     * for comparing other values.
+     *
+     * @static
+     * @memberOf _
+     * @alias eq
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @param {Function} [customizer] The function to customize value comparisons.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
+     * @example
+     *
+     * var object = { 'user': 'fred' };
+     * var other = { 'user': 'fred' };
+     *
+     * object == other;
+     * // => false
+     *
+     * _.isEqual(object, other);
+     * // => true
+     *
+     * // using a customizer callback
+     * var array = ['hello', 'goodbye'];
+     * var other = ['hi', 'goodbye'];
+     *
+     * _.isEqual(array, other, function(value, other) {
+     *   if (_.every([value, other], RegExp.prototype.test, /^h(?:i|ello)$/)) {
+     *     return true;
+     *   }
      * });
-     *
-     * _.filter(characters, 'age__gt38');
-     * // => [{ 'name': 'fred', 'age': 40 }]
-     */
-    function createCallback(func, thisArg, argCount) {
-      var type = typeof func;
-      if (func == null || type == 'function') {
-        return baseCreateCallback(func, thisArg, argCount);
-      }
-      // handle "_.pluck" style callback shorthands
-      if (type != 'object') {
-        return property(func);
-      }
-      var props = keys(func),
-          key = props[0],
-          a = func[key];
-
-      // handle "_.where" style callback shorthands
-      if (props.length == 1 && a === a && !isObject(a)) {
-        // fast path the common case of providing an object with a single
-        // property containing a primitive value
-        return function(object) {
-          var b = object[key];
-          return a === b && (a !== 0 || (1 / a == 1 / b));
-        };
-      }
-      return function(object) {
-        var length = props.length,
-            result = false;
-
-        while (length--) {
-          if (!(result = baseIsEqual(object[props[length]], func[props[length]], null, true))) {
-            break;
-          }
-        }
-        return result;
-      };
-    }
-
-    /**
-     * Converts the characters `&`, `<`, `>`, `"`, and `'` in `string` to their
-     * corresponding HTML entities.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {string} string The string to escape.
-     * @returns {string} Returns the escaped string.
-     * @example
-     *
-     * _.escape('Fred, Wilma, & Pebbles');
-     * // => 'Fred, Wilma, &amp; Pebbles'
-     */
-    function escape(string) {
-      return string == null ? '' : String(string).replace(reUnescapedHtml, escapeHtmlChar);
-    }
-
-    /**
-     * This method returns the first argument provided to it.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {*} value Any value.
-     * @returns {*} Returns `value`.
-     * @example
-     *
-     * var object = { 'name': 'fred' };
-     * _.identity(object) === object;
+     * // => true
+     */
+    function isEqual(value, other, customizer, thisArg) {
+      customizer = typeof customizer == 'function' ? bindCallback(customizer, thisArg, 3) : undefined;
+      var result = customizer ? customizer(value, other) : undefined;
+      return  result === undefined ? baseIsEqual(value, other, customizer) : !!result;
+    }
+
+    /**
+     * Checks if `value` is an `Error`, `EvalError`, `RangeError`, `ReferenceError`,
+     * `SyntaxError`, `TypeError`, or `URIError` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an error object, else `false`.
+     * @example
+     *
+     * _.isError(new Error);
+     * // => true
+     *
+     * _.isError(Error);
+     * // => false
+     */
+    function isError(value) {
+      return isObjectLike(value) && typeof value.message == 'string' && objToString.call(value) == errorTag;
+    }
+
+    /**
+     * Checks if `value` is a finite primitive number.
+     *
+     * **Note:** This method is based on [`Number.isFinite`](http://ecma-international.org/ecma-262/6.0/#sec-number.isfinite).
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a finite number, else `false`.
+     * @example
+     *
+     * _.isFinite(10);
+     * // => true
+     *
+     * _.isFinite('10');
+     * // => false
+     *
+     * _.isFinite(true);
+     * // => false
+     *
+     * _.isFinite(Object(10));
+     * // => false
+     *
+     * _.isFinite(Infinity);
+     * // => false
+     */
+    function isFinite(value) {
+      return typeof value == 'number' && nativeIsFinite(value);
+    }
+
+    /**
+     * Checks if `value` is classified as a `Function` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isFunction(_);
+     * // => true
+     *
+     * _.isFunction(/abc/);
+     * // => false
+     */
+    function isFunction(value) {
+      // The use of `Object#toString` avoids issues with the `typeof` operator
+      // in older versions of Chrome and Safari which return 'function' for regexes
+      // and Safari 8 which returns 'object' for typed array constructors.
+      return isObject(value) && objToString.call(value) == funcTag;
+    }
+
+    /**
+     * Checks if `value` is the [language type](https://es5.github.io/#x8) of `Object`.
+     * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is an object, else `false`.
+     * @example
+     *
+     * _.isObject({});
+     * // => true
+     *
+     * _.isObject([1, 2, 3]);
+     * // => true
+     *
+     * _.isObject(1);
+     * // => false
+     */
+    function isObject(value) {
+      // Avoid a V8 JIT bug in Chrome 19-20.
+      // See https://code.google.com/p/v8/issues/detail?id=2291 for more details.
+      var type = typeof value;
+      return !!value && (type == 'object' || type == 'function');
+    }
+
+    /**
+     * Performs a deep comparison between `object` and `source` to determine if
+     * `object` contains equivalent property values. If `customizer` is provided
+     * it's invoked to compare values. If `customizer` returns `undefined`
+     * comparisons are handled by the method instead. The `customizer` is bound
+     * to `thisArg` and invoked with three arguments: (value, other, index|key).
+     *
+     * **Note:** This method supports comparing properties of arrays, booleans,
+     * `Date` objects, numbers, `Object` objects, regexes, and strings. Functions
+     * and DOM nodes are **not** supported. Provide a customizer function to extend
+     * support for comparing other values.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {Object} object The object to inspect.
+     * @param {Object} source The object of property values to match.
+     * @param {Function} [customizer] The function to customize value comparisons.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {boolean} Returns `true` if `object` is a match, else `false`.
+     * @example
+     *
+     * var object = { 'user': 'fred', 'age': 40 };
+     *
+     * _.isMatch(object, { 'age': 40 });
+     * // => true
+     *
+     * _.isMatch(object, { 'age': 36 });
+     * // => false
+     *
+     * // using a customizer callback
+     * var object = { 'greeting': 'hello' };
+     * var source = { 'greeting': 'hi' };
+     *
+     * _.isMatch(object, source, function(value, other) {
+     *   return _.every([value, other], RegExp.prototype.test, /^h(?:i|ello)$/) || undefined;
+     * });
+     * // => true
+     */
+    function isMatch(object, source, customizer, thisArg) {
+      customizer = typeof customizer == 'function' ? bindCallback(customizer, thisArg, 3) : undefined;
+      return baseIsMatch(object, getMatchData(source), customizer);
+    }
+
+    /**
+     * Checks if `value` is `NaN`.
+     *
+     * **Note:** This method is not the same as [`isNaN`](https://es5.github.io/#x15.1.2.4)
+     * which returns `true` for `undefined` and other non-numeric values.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.
+     * @example
+     *
+     * _.isNaN(NaN);
+     * // => true
+     *
+     * _.isNaN(new Number(NaN));
+     * // => true
+     *
+     * isNaN(undefined);
+     * // => true
+     *
+     * _.isNaN(undefined);
+     * // => false
+     */
+    function isNaN(value) {
+      // An `NaN` primitive is the only value that is not equal to itself.
+      // Perform the `toStringTag` check first to avoid errors with some host objects in IE.
+      return isNumber(value) && value != +value;
+    }
+
+    /**
+     * Checks if `value` is a native function.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a native function, else `false`.
+     * @example
+     *
+     * _.isNative(Array.prototype.push);
+     * // => true
+     *
+     * _.isNative(_);
+     * // => false
+     */
+    function isNative(value) {
+      if (value == null) {
+        return false;
+      }
+      if (isFunction(value)) {
+        return reIsNative.test(fnToString.call(value));
+      }
+      return isObjectLike(value) && reIsHostCtor.test(value);
+    }
+
+    /**
+     * Checks if `value` is `null`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is `null`, else `false`.
+     * @example
+     *
+     * _.isNull(null);
      * // => true
-     */
-    function identity(value) {
-      return value;
-    }
-
-    /**
-     * Adds function properties of a source object to the destination object.
-     * If `object` is a function methods will be added to its prototype as well.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {Function|Object} [object=lodash] object The destination object.
-     * @param {Object} source The object of functions to add.
-     * @param {Object} [options] The options object.
-     * @param {boolean} [options.chain=true] Specify whether the functions added are chainable.
-     * @example
-     *
-     * function capitalize(string) {
-     *   return string.charAt(0).toUpperCase() + string.slice(1).toLowerCase();
+     *
+     * _.isNull(void 0);
+     * // => false
+     */
+    function isNull(value) {
+      return value === null;
+    }
+
+    /**
+     * Checks if `value` is classified as a `Number` primitive or object.
+     *
+     * **Note:** To exclude `Infinity`, `-Infinity`, and `NaN`, which are classified
+     * as numbers, use the `_.isFinite` method.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isNumber(8.4);
+     * // => true
+     *
+     * _.isNumber(NaN);
+     * // => true
+     *
+     * _.isNumber('8.4');
+     * // => false
+     */
+    function isNumber(value) {
+      return typeof value == 'number' || (isObjectLike(value) && objToString.call(value) == numberTag);
+    }
+
+    /**
+     * Checks if `value` is a plain object, that is, an object created by the
+     * `Object` constructor or one with a `[[Prototype]]` of `null`.
+     *
+     * **Note:** This method assumes objects created by the `Object` constructor
+     * have no inherited enumerable properties.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     * }
+     *
+     * _.isPlainObject(new Foo);
+     * // => false
+     *
+     * _.isPlainObject([1, 2, 3]);
+     * // => false
+     *
+     * _.isPlainObject({ 'x': 0, 'y': 0 });
+     * // => true
+     *
+     * _.isPlainObject(Object.create(null));
+     * // => true
+     */
+    function isPlainObject(value) {
+      var Ctor;
+
+      // Exit early for non `Object` objects.
+      if (!(isObjectLike(value) && objToString.call(value) == objectTag && !isArguments(value)) ||
+          (!hasOwnProperty.call(value, 'constructor') && (Ctor = value.constructor, typeof Ctor == 'function' && !(Ctor instanceof Ctor)))) {
+        return false;
+      }
+      // IE < 9 iterates inherited properties before own properties. If the first
+      // iterated property is an object's own property then there are no inherited
+      // enumerable properties.
+      var result;
+      // In most environments an object's own properties are iterated before
+      // its inherited properties. If the last iterated property is an object's
+      // own property then there are no inherited enumerable properties.
+      baseForIn(value, function(subValue, key) {
+        result = key;
+      });
+      return result === undefined || hasOwnProperty.call(value, result);
+    }
+
+    /**
+     * Checks if `value` is classified as a `RegExp` object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isRegExp(/abc/);
+     * // => true
+     *
+     * _.isRegExp('/abc/');
+     * // => false
+     */
+    function isRegExp(value) {
+      return isObject(value) && objToString.call(value) == regexpTag;
+    }
+
+    /**
+     * Checks if `value` is classified as a `String` primitive or object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isString('abc');
+     * // => true
+     *
+     * _.isString(1);
+     * // => false
+     */
+    function isString(value) {
+      return typeof value == 'string' || (isObjectLike(value) && objToString.call(value) == stringTag);
+    }
+
+    /**
+     * Checks if `value` is classified as a typed array.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
+     * @example
+     *
+     * _.isTypedArray(new Uint8Array);
+     * // => true
+     *
+     * _.isTypedArray([]);
+     * // => false
+     */
+    function isTypedArray(value) {
+      return isObjectLike(value) && isLength(value.length) && !!typedArrayTags[objToString.call(value)];
+    }
+
+    /**
+     * Checks if `value` is `undefined`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is `undefined`, else `false`.
+     * @example
+     *
+     * _.isUndefined(void 0);
+     * // => true
+     *
+     * _.isUndefined(null);
+     * // => false
+     */
+    function isUndefined(value) {
+      return value === undefined;
+    }
+
+    /**
+     * Checks if `value` is less than `other`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is less than `other`, else `false`.
+     * @example
+     *
+     * _.lt(1, 3);
+     * // => true
+     *
+     * _.lt(3, 3);
+     * // => false
+     *
+     * _.lt(3, 1);
+     * // => false
+     */
+    function lt(value, other) {
+      return value < other;
+    }
+
+    /**
+     * Checks if `value` is less than or equal to `other`.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to compare.
+     * @param {*} other The other value to compare.
+     * @returns {boolean} Returns `true` if `value` is less than or equal to `other`, else `false`.
+     * @example
+     *
+     * _.lte(1, 3);
+     * // => true
+     *
+     * _.lte(3, 3);
+     * // => true
+     *
+     * _.lte(3, 1);
+     * // => false
+     */
+    function lte(value, other) {
+      return value <= other;
+    }
+
+    /**
+     * Converts `value` to an array.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to convert.
+     * @returns {Array} Returns the converted array.
+     * @example
+     *
+     * (function() {
+     *   return _.toArray(arguments).slice(1);
+     * }(1, 2, 3));
+     * // => [2, 3]
+     */
+    function toArray(value) {
+      var length = value ? getLength(value) : 0;
+      if (!isLength(length)) {
+        return values(value);
+      }
+      if (!length) {
+        return [];
+      }
+      return arrayCopy(value);
+    }
+
+    /**
+     * Converts `value` to a plain object flattening inherited enumerable
+     * properties of `value` to own properties of the plain object.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to convert.
+     * @returns {Object} Returns the converted plain object.
+     * @example
+     *
+     * function Foo() {
+     *   this.b = 2;
      * }
      *
-     * _.mixin({ 'capitalize': capitalize });
-     * _.capitalize('fred');
-     * // => 'Fred'
-     *
-     * _('fred').capitalize().value();
-     * // => 'Fred'
-     *
-     * _.mixin({ 'capitalize': capitalize }, { 'chain': false });
-     * _('fred').capitalize();
-     * // => 'Fred'
-     */
-    function mixin(object, source, options) {
-      var chain = true,
-          methodNames = source && functions(source);
-
-      if (!source || (!options && !methodNames.length)) {
-        if (options == null) {
-          options = source;
-        }
-        ctor = lodashWrapper;
-        source = object;
-        object = lodash;
-        methodNames = functions(source);
-      }
-      if (options === false) {
-        chain = false;
-      } else if (isObject(options) && 'chain' in options) {
-        chain = options.chain;
-      }
-      var ctor = object,
-          isFunc = isFunction(ctor);
-
-      forEach(methodNames, function(methodName) {
-        var func = object[methodName] = source[methodName];
-        if (isFunc) {
-          ctor.prototype[methodName] = function() {
-            var chainAll = this.__chain__,
-                value = this.__wrapped__,
-                args = [value];
-
-            push.apply(args, arguments);
-            var result = func.apply(object, args);
-            if (chain || chainAll) {
-              if (value === result && isObject(result)) {
-                return this;
-              }
-              result = new ctor(result);
-              result.__chain__ = chainAll;
-            }
-            return result;
-          };
-        }
+     * Foo.prototype.c = 3;
+     *
+     * _.assign({ 'a': 1 }, new Foo);
+     * // => { 'a': 1, 'b': 2 }
+     *
+     * _.assign({ 'a': 1 }, _.toPlainObject(new Foo));
+     * // => { 'a': 1, 'b': 2, 'c': 3 }
+     */
+    function toPlainObject(value) {
+      return baseCopy(value, keysIn(value));
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Recursively merges own enumerable properties of the source object(s), that
+     * don't resolve to `undefined` into the destination object. Subsequent sources
+     * overwrite property assignments of previous sources. If `customizer` is
+     * provided it's invoked to produce the merged values of the destination and
+     * source properties. If `customizer` returns `undefined` merging is handled
+     * by the method instead. The `customizer` is bound to `thisArg` and invoked
+     * with five arguments: (objectValue, sourceValue, key, object, source).
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @param {Function} [customizer] The function to customize assigned values.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * var users = {
+     *   'data': [{ 'user': 'barney' }, { 'user': 'fred' }]
+     * };
+     *
+     * var ages = {
+     *   'data': [{ 'age': 36 }, { 'age': 40 }]
+     * };
+     *
+     * _.merge(users, ages);
+     * // => { 'data': [{ 'user': 'barney', 'age': 36 }, { 'user': 'fred', 'age': 40 }] }
+     *
+     * // using a customizer callback
+     * var object = {
+     *   'fruits': ['apple'],
+     *   'vegetables': ['beet']
+     * };
+     *
+     * var other = {
+     *   'fruits': ['banana'],
+     *   'vegetables': ['carrot']
+     * };
+     *
+     * _.merge(object, other, function(a, b) {
+     *   if (_.isArray(a)) {
+     *     return a.concat(b);
+     *   }
+     * });
+     * // => { 'fruits': ['apple', 'banana'], 'vegetables': ['beet', 'carrot'] }
+     */
+    var merge = createAssigner(baseMerge);
+
+    /**
+     * Assigns own enumerable properties of source object(s) to the destination
+     * object. Subsequent sources overwrite property assignments of previous sources.
+     * If `customizer` is provided it's invoked to produce the assigned values.
+     * The `customizer` is bound to `thisArg` and invoked with five arguments:
+     * (objectValue, sourceValue, key, object, source).
+     *
+     * **Note:** This method mutates `object` and is based on
+     * [`Object.assign`](http://ecma-international.org/ecma-262/6.0/#sec-object.assign).
+     *
+     * @static
+     * @memberOf _
+     * @alias extend
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @param {Function} [customizer] The function to customize assigned values.
+     * @param {*} [thisArg] The `this` binding of `customizer`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * _.assign({ 'user': 'barney' }, { 'age': 40 }, { 'user': 'fred' });
+     * // => { 'user': 'fred', 'age': 40 }
+     *
+     * // using a customizer callback
+     * var defaults = _.partialRight(_.assign, function(value, other) {
+     *   return _.isUndefined(value) ? other : value;
+     * });
+     *
+     * defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred' });
+     * // => { 'user': 'barney', 'age': 36 }
+     */
+    var assign = createAssigner(function(object, source, customizer) {
+      return customizer
+        ? assignWith(object, source, customizer)
+        : baseAssign(object, source);
+    });
+
+    /**
+     * Creates an object that inherits from the given `prototype` object. If a
+     * `properties` object is provided its own enumerable properties are assigned
+     * to the created object.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} prototype The object to inherit from.
+     * @param {Object} [properties] The properties to assign to the object.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Object} Returns the new object.
+     * @example
+     *
+     * function Shape() {
+     *   this.x = 0;
+     *   this.y = 0;
+     * }
+     *
+     * function Circle() {
+     *   Shape.call(this);
+     * }
+     *
+     * Circle.prototype = _.create(Shape.prototype, {
+     *   'constructor': Circle
+     * });
+     *
+     * var circle = new Circle;
+     * circle instanceof Circle;
+     * // => true
+     *
+     * circle instanceof Shape;
+     * // => true
+     */
+    function create(prototype, properties, guard) {
+      var result = baseCreate(prototype);
+      if (guard && isIterateeCall(prototype, properties, guard)) {
+        properties = undefined;
+      }
+      return properties ? baseAssign(result, properties) : result;
+    }
+
+    /**
+     * Assigns own enumerable properties of source object(s) to the destination
+     * object for all destination properties that resolve to `undefined`. Once a
+     * property is set, additional values of the same property are ignored.
+     *
+     * **Note:** This method mutates `object`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * _.defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred' });
+     * // => { 'user': 'barney', 'age': 36 }
+     */
+    var defaults = createDefaults(assign, assignDefaults);
+
+    /**
+     * This method is like `_.defaults` except that it recursively assigns
+     * default properties.
+     *
+     * **Note:** This method mutates `object`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The destination object.
+     * @param {...Object} [sources] The source objects.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * _.defaultsDeep({ 'user': { 'name': 'barney' } }, { 'user': { 'name': 'fred', 'age': 36 } });
+     * // => { 'user': { 'name': 'barney', 'age': 36 } }
+     *
+     */
+    var defaultsDeep = createDefaults(merge, mergeDefaults);
+
+    /**
+     * This method is like `_.find` except that it returns the key of the first
+     * element `predicate` returns truthy for instead of the element itself.
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {string|undefined} Returns the key of the matched element, else `undefined`.
+     * @example
+     *
+     * var users = {
+     *   'barney':  { 'age': 36, 'active': true },
+     *   'fred':    { 'age': 40, 'active': false },
+     *   'pebbles': { 'age': 1,  'active': true }
+     * };
+     *
+     * _.findKey(users, function(chr) {
+     *   return chr.age < 40;
+     * });
+     * // => 'barney' (iteration order is not guaranteed)
+     *
+     * // using the `_.matches` callback shorthand
+     * _.findKey(users, { 'age': 1, 'active': true });
+     * // => 'pebbles'
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.findKey(users, 'active', false);
+     * // => 'fred'
+     *
+     * // using the `_.property` callback shorthand
+     * _.findKey(users, 'active');
+     * // => 'barney'
+     */
+    var findKey = createFindKey(baseForOwn);
+
+    /**
+     * This method is like `_.findKey` except that it iterates over elements of
+     * a collection in the opposite order.
+     *
+     * If a property name is provided for `predicate` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `predicate` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to search.
+     * @param {Function|Object|string} [predicate=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {string|undefined} Returns the key of the matched element, else `undefined`.
+     * @example
+     *
+     * var users = {
+     *   'barney':  { 'age': 36, 'active': true },
+     *   'fred':    { 'age': 40, 'active': false },
+     *   'pebbles': { 'age': 1,  'active': true }
+     * };
+     *
+     * _.findLastKey(users, function(chr) {
+     *   return chr.age < 40;
+     * });
+     * // => returns `pebbles` assuming `_.findKey` returns `barney`
+     *
+     * // using the `_.matches` callback shorthand
+     * _.findLastKey(users, { 'age': 36, 'active': true });
+     * // => 'barney'
+     *
+     * // using the `_.matchesProperty` callback shorthand
+     * _.findLastKey(users, 'active', false);
+     * // => 'fred'
+     *
+     * // using the `_.property` callback shorthand
+     * _.findLastKey(users, 'active');
+     * // => 'pebbles'
+     */
+    var findLastKey = createFindKey(baseForOwnRight);
+
+    /**
+     * Iterates over own and inherited enumerable properties of an object invoking
+     * `iteratee` for each property. The `iteratee` is bound to `thisArg` and invoked
+     * with three arguments: (value, key, object). Iteratee functions may exit
+     * iteration early by explicitly returning `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.forIn(new Foo, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => logs 'a', 'b', and 'c' (iteration order is not guaranteed)
+     */
+    var forIn = createForIn(baseFor);
+
+    /**
+     * This method is like `_.forIn` except that it iterates over properties of
+     * `object` in the opposite order.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.forInRight(new Foo, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => logs 'c', 'b', and 'a' assuming `_.forIn ` logs 'a', 'b', and 'c'
+     */
+    var forInRight = createForIn(baseForRight);
+
+    /**
+     * Iterates over own enumerable properties of an object invoking `iteratee`
+     * for each property. The `iteratee` is bound to `thisArg` and invoked with
+     * three arguments: (value, key, object). Iteratee functions may exit iteration
+     * early by explicitly returning `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.forOwn(new Foo, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => logs 'a' and 'b' (iteration order is not guaranteed)
+     */
+    var forOwn = createForOwn(baseForOwn);
+
+    /**
+     * This method is like `_.forOwn` except that it iterates over properties of
+     * `object` in the opposite order.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.forOwnRight(new Foo, function(value, key) {
+     *   console.log(key);
+     * });
+     * // => logs 'b' and 'a' assuming `_.forOwn` logs 'a' and 'b'
+     */
+    var forOwnRight = createForOwn(baseForOwnRight);
+
+    /**
+     * Creates an array of function property names from all enumerable properties,
+     * own and inherited, of `object`.
+     *
+     * @static
+     * @memberOf _
+     * @alias methods
+     * @category Object
+     * @param {Object} object The object to inspect.
+     * @returns {Array} Returns the new array of property names.
+     * @example
+     *
+     * _.functions(_);
+     * // => ['after', 'ary', 'assign', ...]
+     */
+    function functions(object) {
+      return baseFunctions(object, keysIn(object));
+    }
+
+    /**
+     * Gets the property value at `path` of `object`. If the resolved value is
+     * `undefined` the `defaultValue` is used in its place.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the property to get.
+     * @param {*} [defaultValue] The value returned if the resolved value is `undefined`.
+     * @returns {*} Returns the resolved value.
+     * @example
+     *
+     * var object = { 'a': [{ 'b': { 'c': 3 } }] };
+     *
+     * _.get(object, 'a[0].b.c');
+     * // => 3
+     *
+     * _.get(object, ['a', '0', 'b', 'c']);
+     * // => 3
+     *
+     * _.get(object, 'a.b.c', 'default');
+     * // => 'default'
+     */
+    function get(object, path, defaultValue) {
+      var result = object == null ? undefined : baseGet(object, toPath(path), (path + ''));
+      return result === undefined ? defaultValue : result;
+    }
+
+    /**
+     * Checks if `path` is a direct property.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path to check.
+     * @returns {boolean} Returns `true` if `path` is a direct property, else `false`.
+     * @example
+     *
+     * var object = { 'a': { 'b': { 'c': 3 } } };
+     *
+     * _.has(object, 'a');
+     * // => true
+     *
+     * _.has(object, 'a.b.c');
+     * // => true
+     *
+     * _.has(object, ['a', 'b', 'c']);
+     * // => true
+     */
+    function has(object, path) {
+      if (object == null) {
+        return false;
+      }
+      var result = hasOwnProperty.call(object, path);
+      if (!result && !isKey(path)) {
+        path = toPath(path);
+        object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+        if (object == null) {
+          return false;
+        }
+        path = last(path);
+        result = hasOwnProperty.call(object, path);
+      }
+      return result || (isLength(object.length) && isIndex(path, object.length) &&
+        (isArray(object) || isArguments(object)));
+    }
+
+    /**
+     * Creates an object composed of the inverted keys and values of `object`.
+     * If `object` contains duplicate values, subsequent values overwrite property
+     * assignments of previous values unless `multiValue` is `true`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to invert.
+     * @param {boolean} [multiValue] Allow multiple values per key.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Object} Returns the new inverted object.
+     * @example
+     *
+     * var object = { 'a': 1, 'b': 2, 'c': 1 };
+     *
+     * _.invert(object);
+     * // => { '1': 'c', '2': 'b' }
+     *
+     * // with `multiValue`
+     * _.invert(object, true);
+     * // => { '1': ['a', 'c'], '2': ['b'] }
+     */
+    function invert(object, multiValue, guard) {
+      if (guard && isIterateeCall(object, multiValue, guard)) {
+        multiValue = undefined;
+      }
+      var index = -1,
+          props = keys(object),
+          length = props.length,
+          result = {};
+
+      while (++index < length) {
+        var key = props[index],
+            value = object[key];
+
+        if (multiValue) {
+          if (hasOwnProperty.call(result, value)) {
+            result[value].push(key);
+          } else {
+            result[value] = [key];
+          }
+        }
+        else {
+          result[value] = key;
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Creates an array of the own enumerable property names of `object`.
+     *
+     * **Note:** Non-object values are coerced to objects. See the
+     * [ES spec](http://ecma-international.org/ecma-262/6.0/#sec-object.keys)
+     * for more details.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.keys(new Foo);
+     * // => ['a', 'b'] (iteration order is not guaranteed)
+     *
+     * _.keys('hi');
+     * // => ['0', '1']
+     */
+    var keys = !nativeKeys ? shimKeys : function(object) {
+      var Ctor = object == null ? undefined : object.constructor;
+      if ((typeof Ctor == 'function' && Ctor.prototype === object) ||
+          (typeof object != 'function' && isArrayLike(object))) {
+        return shimKeys(object);
+      }
+      return isObject(object) ? nativeKeys(object) : [];
+    };
+
+    /**
+     * Creates an array of the own and inherited enumerable property names of `object`.
+     *
+     * **Note:** Non-object values are coerced to objects.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property names.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.keysIn(new Foo);
+     * // => ['a', 'b', 'c'] (iteration order is not guaranteed)
+     */
+    function keysIn(object) {
+      if (object == null) {
+        return [];
+      }
+      if (!isObject(object)) {
+        object = Object(object);
+      }
+      var length = object.length;
+      length = (length && isLength(length) &&
+        (isArray(object) || isArguments(object)) && length) || 0;
+
+      var Ctor = object.constructor,
+          index = -1,
+          isProto = typeof Ctor == 'function' && Ctor.prototype === object,
+          result = Array(length),
+          skipIndexes = length > 0;
+
+      while (++index < length) {
+        result[index] = (index + '');
+      }
+      for (var key in object) {
+        if (!(skipIndexes && isIndex(key, length)) &&
+            !(key == 'constructor' && (isProto || !hasOwnProperty.call(object, key)))) {
+          result.push(key);
+        }
+      }
+      return result;
+    }
+
+    /**
+     * The opposite of `_.mapValues`; this method creates an object with the
+     * same values as `object` and keys generated by running each own enumerable
+     * property of `object` through `iteratee`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns the new mapped object.
+     * @example
+     *
+     * _.mapKeys({ 'a': 1, 'b': 2 }, function(value, key) {
+     *   return key + value;
+     * });
+     * // => { 'a1': 1, 'b2': 2 }
+     */
+    var mapKeys = createObjectMapper(true);
+
+    /**
+     * Creates an object with the same keys as `object` and values generated by
+     * running each own enumerable property of `object` through `iteratee`. The
+     * iteratee function is bound to `thisArg` and invoked with three arguments:
+     * (value, key, object).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to iterate over.
+     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+     *  per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Object} Returns the new mapped object.
+     * @example
+     *
+     * _.mapValues({ 'a': 1, 'b': 2 }, function(n) {
+     *   return n * 3;
+     * });
+     * // => { 'a': 3, 'b': 6 }
+     *
+     * var users = {
+     *   'fred':    { 'user': 'fred',    'age': 40 },
+     *   'pebbles': { 'user': 'pebbles', 'age': 1 }
+     * };
+     *
+     * // using the `_.property` callback shorthand
+     * _.mapValues(users, 'age');
+     * // => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)
+     */
+    var mapValues = createObjectMapper();
+
+    /**
+     * The opposite of `_.pick`; this method creates an object composed of the
+     * own and inherited enumerable properties of `object` that are not omitted.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The source object.
+     * @param {Function|...(string|string[])} [predicate] The function invoked per
+     *  iteration or property names to omit, specified as individual property
+     *  names or arrays of property names.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Object} Returns the new object.
+     * @example
+     *
+     * var object = { 'user': 'fred', 'age': 40 };
+     *
+     * _.omit(object, 'age');
+     * // => { 'user': 'fred' }
+     *
+     * _.omit(object, _.isNumber);
+     * // => { 'user': 'fred' }
+     */
+    var omit = restParam(function(object, props) {
+      if (object == null) {
+        return {};
+      }
+      if (typeof props[0] != 'function') {
+        var props = arrayMap(baseFlatten(props), String);
+        return pickByArray(object, baseDifference(keysIn(object), props));
+      }
+      var predicate = bindCallback(props[0], props[1], 3);
+      return pickByCallback(object, function(value, key, object) {
+        return !predicate(value, key, object);
       });
-    }
-
-    /**
-     * Reverts the '_' variable to its previous value and returns a reference to
-     * the `lodash` function.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @returns {Function} Returns the `lodash` function.
-     * @example
-     *
-     * var lodash = _.noConflict();
-     */
-    function noConflict() {
-      context._ = oldDash;
-      return this;
-    }
-
-    /**
-     * A no-operation function.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @example
-     *
-     * var object = { 'name': 'fred' };
-     * _.noop(object) === undefined;
+    });
+
+    /**
+     * Creates a two dimensional array of the key-value pairs for `object`,
+     * e.g. `[[key1, value1], [key2, value2]]`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the new array of key-value pairs.
+     * @example
+     *
+     * _.pairs({ 'barney': 36, 'fred': 40 });
+     * // => [['barney', 36], ['fred', 40]] (iteration order is not guaranteed)
+     */
+    function pairs(object) {
+      object = toObject(object);
+
+      var index = -1,
+          props = keys(object),
+          length = props.length,
+          result = Array(length);
+
+      while (++index < length) {
+        var key = props[index];
+        result[index] = [key, object[key]];
+      }
+      return result;
+    }
+
+    /**
+     * Creates an object composed of the picked `object` properties. Property
+     * names may be specified as individual arguments or as arrays of property
+     * names. If `predicate` is provided it's invoked for each property of `object`
+     * picking the properties `predicate` returns truthy for. The predicate is
+     * bound to `thisArg` and invoked with three arguments: (value, key, object).
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The source object.
+     * @param {Function|...(string|string[])} [predicate] The function invoked per
+     *  iteration or property names to pick, specified as individual property
+     *  names or arrays of property names.
+     * @param {*} [thisArg] The `this` binding of `predicate`.
+     * @returns {Object} Returns the new object.
+     * @example
+     *
+     * var object = { 'user': 'fred', 'age': 40 };
+     *
+     * _.pick(object, 'user');
+     * // => { 'user': 'fred' }
+     *
+     * _.pick(object, _.isString);
+     * // => { 'user': 'fred' }
+     */
+    var pick = restParam(function(object, props) {
+      if (object == null) {
+        return {};
+      }
+      return typeof props[0] == 'function'
+        ? pickByCallback(object, bindCallback(props[0], props[1], 3))
+        : pickByArray(object, baseFlatten(props));
+    });
+
+    /**
+     * This method is like `_.get` except that if the resolved value is a function
+     * it's invoked with the `this` binding of its parent object and its result
+     * is returned.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the property to resolve.
+     * @param {*} [defaultValue] The value returned if the resolved value is `undefined`.
+     * @returns {*} Returns the resolved value.
+     * @example
+     *
+     * var object = { 'a': [{ 'b': { 'c1': 3, 'c2': _.constant(4) } }] };
+     *
+     * _.result(object, 'a[0].b.c1');
+     * // => 3
+     *
+     * _.result(object, 'a[0].b.c2');
+     * // => 4
+     *
+     * _.result(object, 'a.b.c', 'default');
+     * // => 'default'
+     *
+     * _.result(object, 'a.b.c', _.constant('default'));
+     * // => 'default'
+     */
+    function result(object, path, defaultValue) {
+      var result = object == null ? undefined : object[path];
+      if (result === undefined) {
+        if (object != null && !isKey(path, object)) {
+          path = toPath(path);
+          object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+          result = object == null ? undefined : object[last(path)];
+        }
+        result = result === undefined ? defaultValue : result;
+      }
+      return isFunction(result) ? result.call(object) : result;
+    }
+
+    /**
+     * Sets the property value of `path` on `object`. If a portion of `path`
+     * does not exist it's created.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to augment.
+     * @param {Array|string} path The path of the property to set.
+     * @param {*} value The value to set.
+     * @returns {Object} Returns `object`.
+     * @example
+     *
+     * var object = { 'a': [{ 'b': { 'c': 3 } }] };
+     *
+     * _.set(object, 'a[0].b.c', 4);
+     * console.log(object.a[0].b.c);
+     * // => 4
+     *
+     * _.set(object, 'x[0].y.z', 5);
+     * console.log(object.x[0].y.z);
+     * // => 5
+     */
+    function set(object, path, value) {
+      if (object == null) {
+        return object;
+      }
+      var pathKey = (path + '');
+      path = (object[pathKey] != null || isKey(path, object)) ? [pathKey] : toPath(path);
+
+      var index = -1,
+          length = path.length,
+          lastIndex = length - 1,
+          nested = object;
+
+      while (nested != null && ++index < length) {
+        var key = path[index];
+        if (isObject(nested)) {
+          if (index == lastIndex) {
+            nested[key] = value;
+          } else if (nested[key] == null) {
+            nested[key] = isIndex(path[index + 1]) ? [] : {};
+          }
+        }
+        nested = nested[key];
+      }
+      return object;
+    }
+
+    /**
+     * An alternative to `_.reduce`; this method transforms `object` to a new
+     * `accumulator` object which is the result of running each of its own enumerable
+     * properties through `iteratee`, with each invocation potentially mutating
+     * the `accumulator` object. The `iteratee` is bound to `thisArg` and invoked
+     * with four arguments: (accumulator, value, key, object). Iteratee functions
+     * may exit iteration early by explicitly returning `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Array|Object} object The object to iterate over.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [accumulator] The custom accumulator value.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {*} Returns the accumulated value.
+     * @example
+     *
+     * _.transform([2, 3, 4], function(result, n) {
+     *   result.push(n *= n);
+     *   return n % 2 == 0;
+     * });
+     * // => [4, 9]
+     *
+     * _.transform({ 'a': 1, 'b': 2 }, function(result, n, key) {
+     *   result[key] = n * 3;
+     * });
+     * // => { 'a': 3, 'b': 6 }
+     */
+    function transform(object, iteratee, accumulator, thisArg) {
+      var isArr = isArray(object) || isTypedArray(object);
+      iteratee = getCallback(iteratee, thisArg, 4);
+
+      if (accumulator == null) {
+        if (isArr || isObject(object)) {
+          var Ctor = object.constructor;
+          if (isArr) {
+            accumulator = isArray(object) ? new Ctor : [];
+          } else {
+            accumulator = baseCreate(isFunction(Ctor) ? Ctor.prototype : undefined);
+          }
+        } else {
+          accumulator = {};
+        }
+      }
+      (isArr ? arrayEach : baseForOwn)(object, function(value, index, object) {
+        return iteratee(accumulator, value, index, object);
+      });
+      return accumulator;
+    }
+
+    /**
+     * Creates an array of the own enumerable property values of `object`.
+     *
+     * **Note:** Non-object values are coerced to objects.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property values.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.values(new Foo);
+     * // => [1, 2] (iteration order is not guaranteed)
+     *
+     * _.values('hi');
+     * // => ['h', 'i']
+     */
+    function values(object) {
+      return baseValues(object, keys(object));
+    }
+
+    /**
+     * Creates an array of the own and inherited enumerable property values
+     * of `object`.
+     *
+     * **Note:** Non-object values are coerced to objects.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @returns {Array} Returns the array of property values.
+     * @example
+     *
+     * function Foo() {
+     *   this.a = 1;
+     *   this.b = 2;
+     * }
+     *
+     * Foo.prototype.c = 3;
+     *
+     * _.valuesIn(new Foo);
+     * // => [1, 2, 3] (iteration order is not guaranteed)
+     */
+    function valuesIn(object) {
+      return baseValues(object, keysIn(object));
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Checks if `n` is between `start` and up to but not including, `end`. If
+     * `end` is not specified it's set to `start` with `start` then set to `0`.
+     *
+     * @static
+     * @memberOf _
+     * @category Number
+     * @param {number} n The number to check.
+     * @param {number} [start=0] The start of the range.
+     * @param {number} end The end of the range.
+     * @returns {boolean} Returns `true` if `n` is in the range, else `false`.
+     * @example
+     *
+     * _.inRange(3, 2, 4);
      * // => true
-     */
-    function noop() {
-      // no operation performed
-    }
-
-    /**
-     * Gets the number of milliseconds that have elapsed since the Unix epoch
-     * (1 January 1970 00:00:00 UTC).
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @example
-     *
-     * var stamp = _.now();
-     * _.defer(function() { console.log(_.now() - stamp); });
-     * // => logs the number of milliseconds it took for the deferred function to be called
-     */
-    var now = isNative(now = Date.now) && now || function() {
-      return new Date().getTime();
-    };
-
-    /**
-     * Converts the given value into an integer of the specified radix.
-     * If `radix` is `undefined` or `0` a `radix` of `10` is used unless the
-     * `value` is a hexadecimal, in which case a `radix` of `16` is used.
-     *
-     * Note: This method avoids differences in native ES3 and ES5 `parseInt`
-     * implementations. See http://es5.github.io/#E.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {string} value The value to parse.
-     * @param {number} [radix] The radix used to interpret the value to parse.
-     * @returns {number} Returns the new integer value.
-     * @example
-     *
-     * _.parseInt('08');
-     * // => 8
-     */
-    var parseInt = nativeParseInt(whitespace + '08') == 8 ? nativeParseInt : function(value, radix) {
-      // Firefox < 21 and Opera < 15 follow the ES3 specified implementation of `parseInt`
-      return nativeParseInt(isString(value) ? value.replace(reLeadingSpacesAndZeros, '') : value, radix || 0);
-    };
-
-    /**
-     * Creates a "_.pluck" style function, which returns the `key` value of a
-     * given object.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {string} key The name of the property to retrieve.
-     * @returns {Function} Returns the new function.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'fred',   'age': 40 },
-     *   { 'name': 'barney', 'age': 36 }
-     * ];
-     *
-     * var getName = _.property('name');
-     *
-     * _.map(characters, getName);
-     * // => ['barney', 'fred']
-     *
-     * _.sortBy(characters, getName);
-     * // => [{ 'name': 'barney', 'age': 36 }, { 'name': 'fred',   'age': 40 }]
-     */
-    function property(key) {
-      return function(object) {
-        return object[key];
-      };
+     *
+     * _.inRange(4, 8);
+     * // => true
+     *
+     * _.inRange(4, 2);
+     * // => false
+     *
+     * _.inRange(2, 2);
+     * // => false
+     *
+     * _.inRange(1.2, 2);
+     * // => true
+     *
+     * _.inRange(5.2, 4);
+     * // => false
+     */
+    function inRange(value, start, end) {
+      start = +start || 0;
+      if (end === undefined) {
+        end = start;
+        start = 0;
+      } else {
+        end = +end || 0;
+      }
+      return value >= nativeMin(start, end) && value < nativeMax(start, end);
     }
 
     /**
      * Produces a random number between `min` and `max` (inclusive). If only one
-     * argument is provided a number between `0` and the given number will be
-     * returned. If `floating` is truey or either `min` or `max` are floats a
-     * floating-point number will be returned instead of an integer.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
+     * argument is provided a number between `0` and the given number is returned.
+     * If `floating` is `true`, or either `min` or `max` are floats, a floating-point
+     * number is returned instead of an integer.
+     *
+     * @static
+     * @memberOf _
+     * @category Number
      * @param {number} [min=0] The minimum possible value.
      * @param {number} [max=1] The maximum possible value.
-     * @param {boolean} [floating=false] Specify returning a floating-point number.
-     * @returns {number} Returns a random number.
+     * @param {boolean} [floating] Specify returning a floating-point number.
+     * @returns {number} Returns the random number.
      * @example
      *
      * _.random(0, 5);
@@ -6068,21 +10164,25 @@
      * // => a floating-point number between 1.2 and 5.2
      */
     function random(min, max, floating) {
+      if (floating && isIterateeCall(min, max, floating)) {
+        max = floating = undefined;
+      }
       var noMin = min == null,
           noMax = max == null;
 
       if (floating == null) {
-        if (typeof min == 'boolean' && noMax) {
+        if (noMax && typeof min == 'boolean') {
           floating = min;
           min = 1;
         }
-        else if (!noMax && typeof max == 'boolean') {
+        else if (typeof max == 'boolean') {
           floating = max;
           noMax = true;
         }
       }
       if (noMin && noMax) {
         max = 1;
+        noMax = false;
       }
       min = +min || 0;
       if (noMax) {
@@ -6093,122 +10193,517 @@
       }
       if (floating || min % 1 || max % 1) {
         var rand = nativeRandom();
-        return nativeMin(min + (rand * (max - min + parseFloat('1e-' + ((rand +'').length - 1)))), max);
+        return nativeMin(min + (rand * (max - min + parseFloat('1e-' + ((rand + '').length - 1)))), max);
       }
       return baseRandom(min, max);
     }
 
-    /**
-     * Resolves the value of property `key` on `object`. If `key` is a function
-     * it will be invoked with the `this` binding of `object` and its result returned,
-     * else the property value is returned. If `object` is falsey then `undefined`
-     * is returned.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {Object} object The object to inspect.
-     * @param {string} key The name of the property to resolve.
-     * @returns {*} Returns the resolved value.
-     * @example
-     *
-     * var object = {
-     *   'cheese': 'crumpets',
-     *   'stuff': function() {
-     *     return 'nonsense';
-     *   }
-     * };
-     *
-     * _.result(object, 'cheese');
-     * // => 'crumpets'
-     *
-     * _.result(object, 'stuff');
-     * // => 'nonsense'
-     */
-    function result(object, key) {
-      if (object) {
-        var value = object[key];
-        return isFunction(value) ? object[key]() : value;
-      }
-    }
-
-    /**
-     * A micro-templating method that handles arbitrary delimiters, preserves
-     * whitespace, and correctly escapes quotes within interpolated code.
-     *
-     * Note: In the development build, `_.template` utilizes sourceURLs for easier
-     * debugging. See http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl
-     *
-     * For more information on precompiling templates see:
-     * https://lodash.com/custom-builds
-     *
-     * For more information on Chrome extension sandboxes see:
-     * http://developer.chrome.com/stable/extensions/sandboxingEval.html
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {string} text The template text.
-     * @param {Object} data The data object used to populate the text.
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Converts `string` to [camel case](https://en.wikipedia.org/wiki/CamelCase).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the camel cased string.
+     * @example
+     *
+     * _.camelCase('Foo Bar');
+     * // => 'fooBar'
+     *
+     * _.camelCase('--foo-bar');
+     * // => 'fooBar'
+     *
+     * _.camelCase('__foo_bar__');
+     * // => 'fooBar'
+     */
+    var camelCase = createCompounder(function(result, word, index) {
+      word = word.toLowerCase();
+      return result + (index ? (word.charAt(0).toUpperCase() + word.slice(1)) : word);
+    });
+
+    /**
+     * Capitalizes the first character of `string`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to capitalize.
+     * @returns {string} Returns the capitalized string.
+     * @example
+     *
+     * _.capitalize('fred');
+     * // => 'Fred'
+     */
+    function capitalize(string) {
+      string = baseToString(string);
+      return string && (string.charAt(0).toUpperCase() + string.slice(1));
+    }
+
+    /**
+     * Deburrs `string` by converting [latin-1 supplementary letters](https://en.wikipedia.org/wiki/Latin-1_Supplement_(Unicode_block)#Character_table)
+     * to basic latin letters and removing [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to deburr.
+     * @returns {string} Returns the deburred string.
+     * @example
+     *
+     * _.deburr('déjà vu');
+     * // => 'deja vu'
+     */
+    function deburr(string) {
+      string = baseToString(string);
+      return string && string.replace(reLatin1, deburrLetter).replace(reComboMark, '');
+    }
+
+    /**
+     * Checks if `string` ends with the given target string.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to search.
+     * @param {string} [target] The string to search for.
+     * @param {number} [position=string.length] The position to search from.
+     * @returns {boolean} Returns `true` if `string` ends with `target`, else `false`.
+     * @example
+     *
+     * _.endsWith('abc', 'c');
+     * // => true
+     *
+     * _.endsWith('abc', 'b');
+     * // => false
+     *
+     * _.endsWith('abc', 'b', 2);
+     * // => true
+     */
+    function endsWith(string, target, position) {
+      string = baseToString(string);
+      target = (target + '');
+
+      var length = string.length;
+      position = position === undefined
+        ? length
+        : nativeMin(position < 0 ? 0 : (+position || 0), length);
+
+      position -= target.length;
+      return position >= 0 && string.indexOf(target, position) == position;
+    }
+
+    /**
+     * Converts the characters "&", "<", ">", '"', "'", and "\`", in `string` to
+     * their corresponding HTML entities.
+     *
+     * **Note:** No other characters are escaped. To escape additional characters
+     * use a third-party library like [_he_](https://mths.be/he).
+     *
+     * Though the ">" character is escaped for symmetry, characters like
+     * ">" and "/" don't need escaping in HTML and have no special meaning
+     * unless they're part of a tag or unquoted attribute value.
+     * See [Mathias Bynens's article](https://mathiasbynens.be/notes/ambiguous-ampersands)
+     * (under "semi-related fun fact") for more details.
+     *
+     * Backticks are escaped because in Internet Explorer < 9, they can break out
+     * of attribute values or HTML comments. See [#59](https://html5sec.org/#59),
+     * [#102](https://html5sec.org/#102), [#108](https://html5sec.org/#108), and
+     * [#133](https://html5sec.org/#133) of the [HTML5 Security Cheatsheet](https://html5sec.org/)
+     * for more details.
+     *
+     * When working with HTML you should always [quote attribute values](http://wonko.com/post/html-escaping)
+     * to reduce XSS vectors.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to escape.
+     * @returns {string} Returns the escaped string.
+     * @example
+     *
+     * _.escape('fred, barney, & pebbles');
+     * // => 'fred, barney, &amp; pebbles'
+     */
+    function escape(string) {
+      // Reset `lastIndex` because in IE < 9 `String#replace` does not.
+      string = baseToString(string);
+      return (string && reHasUnescapedHtml.test(string))
+        ? string.replace(reUnescapedHtml, escapeHtmlChar)
+        : string;
+    }
+
+    /**
+     * Escapes the `RegExp` special characters "\", "/", "^", "$", ".", "|", "?",
+     * "*", "+", "(", ")", "[", "]", "{" and "}" in `string`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to escape.
+     * @returns {string} Returns the escaped string.
+     * @example
+     *
+     * _.escapeRegExp('[lodash](https://lodash.com/)');
+     * // => '\[lodash\]\(https:\/\/lodash\.com\/\)'
+     */
+    function escapeRegExp(string) {
+      string = baseToString(string);
+      return (string && reHasRegExpChars.test(string))
+        ? string.replace(reRegExpChars, escapeRegExpChar)
+        : (string || '(?:)');
+    }
+
+    /**
+     * Converts `string` to [kebab case](https://en.wikipedia.org/wiki/Letter_case#Special_case_styles).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the kebab cased string.
+     * @example
+     *
+     * _.kebabCase('Foo Bar');
+     * // => 'foo-bar'
+     *
+     * _.kebabCase('fooBar');
+     * // => 'foo-bar'
+     *
+     * _.kebabCase('__foo_bar__');
+     * // => 'foo-bar'
+     */
+    var kebabCase = createCompounder(function(result, word, index) {
+      return result + (index ? '-' : '') + word.toLowerCase();
+    });
+
+    /**
+     * Pads `string` on the left and right sides if it's shorter than `length`.
+     * Padding characters are truncated if they can't be evenly divided by `length`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to pad.
+     * @param {number} [length=0] The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the padded string.
+     * @example
+     *
+     * _.pad('abc', 8);
+     * // => '  abc   '
+     *
+     * _.pad('abc', 8, '_-');
+     * // => '_-abc_-_'
+     *
+     * _.pad('abc', 3);
+     * // => 'abc'
+     */
+    function pad(string, length, chars) {
+      string = baseToString(string);
+      length = +length;
+
+      var strLength = string.length;
+      if (strLength >= length || !nativeIsFinite(length)) {
+        return string;
+      }
+      var mid = (length - strLength) / 2,
+          leftLength = nativeFloor(mid),
+          rightLength = nativeCeil(mid);
+
+      chars = createPadding('', rightLength, chars);
+      return chars.slice(0, leftLength) + string + chars;
+    }
+
+    /**
+     * Pads `string` on the left side if it's shorter than `length`. Padding
+     * characters are truncated if they exceed `length`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to pad.
+     * @param {number} [length=0] The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the padded string.
+     * @example
+     *
+     * _.padLeft('abc', 6);
+     * // => '   abc'
+     *
+     * _.padLeft('abc', 6, '_-');
+     * // => '_-_abc'
+     *
+     * _.padLeft('abc', 3);
+     * // => 'abc'
+     */
+    var padLeft = createPadDir();
+
+    /**
+     * Pads `string` on the right side if it's shorter than `length`. Padding
+     * characters are truncated if they exceed `length`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to pad.
+     * @param {number} [length=0] The padding length.
+     * @param {string} [chars=' '] The string used as padding.
+     * @returns {string} Returns the padded string.
+     * @example
+     *
+     * _.padRight('abc', 6);
+     * // => 'abc   '
+     *
+     * _.padRight('abc', 6, '_-');
+     * // => 'abc_-_'
+     *
+     * _.padRight('abc', 3);
+     * // => 'abc'
+     */
+    var padRight = createPadDir(true);
+
+    /**
+     * Converts `string` to an integer of the specified radix. If `radix` is
+     * `undefined` or `0`, a `radix` of `10` is used unless `value` is a hexadecimal,
+     * in which case a `radix` of `16` is used.
+     *
+     * **Note:** This method aligns with the [ES5 implementation](https://es5.github.io/#E)
+     * of `parseInt`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} string The string to convert.
+     * @param {number} [radix] The radix to interpret `value` by.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {number} Returns the converted integer.
+     * @example
+     *
+     * _.parseInt('08');
+     * // => 8
+     *
+     * _.map(['6', '08', '10'], _.parseInt);
+     * // => [6, 8, 10]
+     */
+    function parseInt(string, radix, guard) {
+      // Firefox < 21 and Opera < 15 follow ES3 for `parseInt`.
+      // Chrome fails to trim leading <BOM> whitespace characters.
+      // See https://code.google.com/p/v8/issues/detail?id=3109 for more details.
+      if (guard ? isIterateeCall(string, radix, guard) : radix == null) {
+        radix = 0;
+      } else if (radix) {
+        radix = +radix;
+      }
+      string = trim(string);
+      return nativeParseInt(string, radix || (reHasHexPrefix.test(string) ? 16 : 10));
+    }
+
+    /**
+     * Repeats the given string `n` times.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to repeat.
+     * @param {number} [n=0] The number of times to repeat the string.
+     * @returns {string} Returns the repeated string.
+     * @example
+     *
+     * _.repeat('*', 3);
+     * // => '***'
+     *
+     * _.repeat('abc', 2);
+     * // => 'abcabc'
+     *
+     * _.repeat('abc', 0);
+     * // => ''
+     */
+    function repeat(string, n) {
+      var result = '';
+      string = baseToString(string);
+      n = +n;
+      if (n < 1 || !string || !nativeIsFinite(n)) {
+        return result;
+      }
+      // Leverage the exponentiation by squaring algorithm for a faster repeat.
+      // See https://en.wikipedia.org/wiki/Exponentiation_by_squaring for more details.
+      do {
+        if (n % 2) {
+          result += string;
+        }
+        n = nativeFloor(n / 2);
+        string += string;
+      } while (n);
+
+      return result;
+    }
+
+    /**
+     * Converts `string` to [snake case](https://en.wikipedia.org/wiki/Snake_case).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the snake cased string.
+     * @example
+     *
+     * _.snakeCase('Foo Bar');
+     * // => 'foo_bar'
+     *
+     * _.snakeCase('fooBar');
+     * // => 'foo_bar'
+     *
+     * _.snakeCase('--foo-bar');
+     * // => 'foo_bar'
+     */
+    var snakeCase = createCompounder(function(result, word, index) {
+      return result + (index ? '_' : '') + word.toLowerCase();
+    });
+
+    /**
+     * Converts `string` to [start case](https://en.wikipedia.org/wiki/Letter_case#Stylistic_or_specialised_usage).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to convert.
+     * @returns {string} Returns the start cased string.
+     * @example
+     *
+     * _.startCase('--foo-bar');
+     * // => 'Foo Bar'
+     *
+     * _.startCase('fooBar');
+     * // => 'Foo Bar'
+     *
+     * _.startCase('__foo_bar__');
+     * // => 'Foo Bar'
+     */
+    var startCase = createCompounder(function(result, word, index) {
+      return result + (index ? ' ' : '') + (word.charAt(0).toUpperCase() + word.slice(1));
+    });
+
+    /**
+     * Checks if `string` starts with the given target string.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to search.
+     * @param {string} [target] The string to search for.
+     * @param {number} [position=0] The position to search from.
+     * @returns {boolean} Returns `true` if `string` starts with `target`, else `false`.
+     * @example
+     *
+     * _.startsWith('abc', 'a');
+     * // => true
+     *
+     * _.startsWith('abc', 'b');
+     * // => false
+     *
+     * _.startsWith('abc', 'b', 1);
+     * // => true
+     */
+    function startsWith(string, target, position) {
+      string = baseToString(string);
+      position = position == null
+        ? 0
+        : nativeMin(position < 0 ? 0 : (+position || 0), string.length);
+
+      return string.lastIndexOf(target, position) == position;
+    }
+
+    /**
+     * Creates a compiled template function that can interpolate data properties
+     * in "interpolate" delimiters, HTML-escape interpolated data properties in
+     * "escape" delimiters, and execute JavaScript in "evaluate" delimiters. Data
+     * properties may be accessed as free variables in the template. If a setting
+     * object is provided it takes precedence over `_.templateSettings` values.
+     *
+     * **Note:** In the development build `_.template` utilizes
+     * [sourceURLs](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl)
+     * for easier debugging.
+     *
+     * For more information on precompiling templates see
+     * [lodash's custom builds documentation](https://lodash.com/custom-builds).
+     *
+     * For more information on Chrome extension sandboxes see
+     * [Chrome's extensions documentation](https://developer.chrome.com/extensions/sandboxingEval).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The template string.
      * @param {Object} [options] The options object.
-     * @param {RegExp} [options.escape] The "escape" delimiter.
+     * @param {RegExp} [options.escape] The HTML "escape" delimiter.
      * @param {RegExp} [options.evaluate] The "evaluate" delimiter.
-     * @param {Object} [options.imports] An object to import into the template as local variables.
+     * @param {Object} [options.imports] An object to import into the template as free variables.
      * @param {RegExp} [options.interpolate] The "interpolate" delimiter.
-     * @param {string} [sourceURL] The sourceURL of the template's compiled source.
-     * @param {string} [variable] The data object variable name.
-     * @returns {Function|string} Returns a compiled function when no `data` object
-     *  is given, else it returns the interpolated text.
+     * @param {string} [options.sourceURL] The sourceURL of the template's compiled source.
+     * @param {string} [options.variable] The data object variable name.
+     * @param- {Object} [otherOptions] Enables the legacy `options` param signature.
+     * @returns {Function} Returns the compiled template function.
      * @example
      *
      * // using the "interpolate" delimiter to create a compiled template
-     * var compiled = _.template('hello <%= name %>');
-     * compiled({ 'name': 'fred' });
-     * // => 'hello fred'
-     *
-     * // using the "escape" delimiter to escape HTML in data property values
-     * _.template('<b><%- value %></b>', { 'value': '<script>' });
+     * var compiled = _.template('hello <%= user %>!');
+     * compiled({ 'user': 'fred' });
+     * // => 'hello fred!'
+     *
+     * // using the HTML "escape" delimiter to escape data property values
+     * var compiled = _.template('<b><%- value %></b>');
+     * compiled({ 'value': '<script>' });
      * // => '<b>&lt;script&gt;</b>'
      *
-     * // using the "evaluate" delimiter to generate HTML
-     * var list = '<% _.forEach(people, function(name) { %><li><%- name %></li><% }); %>';
-     * _.template(list, { 'people': ['fred', 'barney'] });
+     * // using the "evaluate" delimiter to execute JavaScript and generate HTML
+     * var compiled = _.template('<% _.forEach(users, function(user) { %><li><%- user %></li><% }); %>');
+     * compiled({ 'users': ['fred', 'barney'] });
      * // => '<li>fred</li><li>barney</li>'
      *
-     * // using the ES6 delimiter as an alternative to the default "interpolate" delimiter
-     * _.template('hello ${ name }', { 'name': 'pebbles' });
-     * // => 'hello pebbles'
-     *
      * // using the internal `print` function in "evaluate" delimiters
-     * _.template('<% print("hello " + name); %>!', { 'name': 'barney' });
+     * var compiled = _.template('<% print("hello " + user); %>!');
+     * compiled({ 'user': 'barney' });
      * // => 'hello barney!'
      *
-     * // using a custom template delimiters
-     * _.templateSettings = {
-     *   'interpolate': /{{([\s\S]+?)}}/g
-     * };
-     *
-     * _.template('hello {{ name }}!', { 'name': 'mustache' });
+     * // using the ES delimiter as an alternative to the default "interpolate" delimiter
+     * var compiled = _.template('hello ${ user }!');
+     * compiled({ 'user': 'pebbles' });
+     * // => 'hello pebbles!'
+     *
+     * // using custom template delimiters
+     * _.templateSettings.interpolate = /{{([\s\S]+?)}}/g;
+     * var compiled = _.template('hello {{ user }}!');
+     * compiled({ 'user': 'mustache' });
      * // => 'hello mustache!'
      *
-     * // using the `imports` option to import jQuery
-     * var list = '<% jq.each(people, function(name) { %><li><%- name %></li><% }); %>';
-     * _.template(list, { 'people': ['fred', 'barney'] }, { 'imports': { 'jq': jQuery } });
+     * // using backslashes to treat delimiters as plain text
+     * var compiled = _.template('<%= "\\<%- value %\\>" %>');
+     * compiled({ 'value': 'ignored' });
+     * // => '<%- value %>'
+     *
+     * // using the `imports` option to import `jQuery` as `jq`
+     * var text = '<% jq.each(users, function(user) { %><li><%- user %></li><% }); %>';
+     * var compiled = _.template(text, { 'imports': { 'jq': jQuery } });
+     * compiled({ 'users': ['fred', 'barney'] });
      * // => '<li>fred</li><li>barney</li>'
      *
      * // using the `sourceURL` option to specify a custom sourceURL for the template
-     * var compiled = _.template('hello <%= name %>', null, { 'sourceURL': '/basic/greeting.jst' });
+     * var compiled = _.template('hello <%= user %>!', { 'sourceURL': '/basic/greeting.jst' });
      * compiled(data);
      * // => find the source of "greeting.jst" under the Sources tab or Resources panel of the web inspector
      *
      * // using the `variable` option to ensure a with-statement isn't used in the compiled template
-     * var compiled = _.template('hi <%= data.name %>!', null, { 'variable': 'data' });
+     * var compiled = _.template('hi <%= data.user %>!', { 'variable': 'data' });
      * compiled.source;
      * // => function(data) {
-     *   var __t, __p = '', __e = _.escape;
-     *   __p += 'hi ' + ((__t = ( data.name )) == null ? '' : __t) + '!';
-     *   return __p;
-     * }
+     * //   var __t, __p = '';
+     * //   __p += 'hi ' + ((__t = ( data.user )) == null ? '' : __t) + '!';
+     * //   return __p;
+     * // }
      *
      * // using the `source` property to inline compiled templates for meaningful
      * // line numbers in error messages and a stack trace
@@ -6218,27 +10713,28 @@
      *   };\
      * ');
      */
-    function template(text, data, options) {
-      // based on John Resig's `tmpl` implementation
-      // http://ejohn.org/blog/javascript-micro-templating/
-      // and Laura Doktorova's doT.js
-      // https://github.com/olado/doT
+    function template(string, options, otherOptions) {
+      // Based on John Resig's `tmpl` implementation (http://ejohn.org/blog/javascript-micro-templating/)
+      // and Laura Doktorova's doT.js (https://github.com/olado/doT).
       var settings = lodash.templateSettings;
-      text = String(text || '');
-
-      // avoid missing dependencies when `iteratorTemplate` is not defined
-      options = defaults({}, options, settings);
-
-      var imports = defaults({}, options.imports, settings.imports),
+
+      if (otherOptions && isIterateeCall(string, options, otherOptions)) {
+        options = otherOptions = undefined;
+      }
+      string = baseToString(string);
+      options = assignWith(baseAssign({}, otherOptions || options), settings, assignOwnDefaults);
+
+      var imports = assignWith(baseAssign({}, options.imports), settings.imports, assignOwnDefaults),
           importsKeys = keys(imports),
-          importsValues = values(imports);
-
-      var isEvaluating,
+          importsValues = baseValues(imports, importsKeys);
+
+      var isEscaping,
+          isEvaluating,
           index = 0,
           interpolate = options.interpolate || reNoMatch,
           source = "__p += '";
 
-      // compile the regexp to match each delimiter
+      // Compile the regexp to match each delimiter.
       var reDelimiters = RegExp(
         (options.escape || reNoMatch).source + '|' +
         interpolate.source + '|' +
@@ -6246,14 +10742,22 @@
         (options.evaluate || reNoMatch).source + '|$'
       , 'g');
 
-      text.replace(reDelimiters, function(match, escapeValue, interpolateValue, esTemplateValue, evaluateValue, offset) {
+      // Use a sourceURL for easier debugging.
+      var sourceURL = '//# sourceURL=' +
+        ('sourceURL' in options
+          ? options.sourceURL
+          : ('lodash.templateSources[' + (++templateCounter) + ']')
+        ) + '\n';
+
+      string.replace(reDelimiters, function(match, escapeValue, interpolateValue, esTemplateValue, evaluateValue, offset) {
         interpolateValue || (interpolateValue = esTemplateValue);
 
-        // escape characters that cannot be included in string literals
-        source += text.slice(index, offset).replace(reUnescapedString, escapeStringChar);
-
-        // replace delimiters with snippets
+        // Escape characters that can't be included in string literals.
+        source += string.slice(index, offset).replace(reUnescapedString, escapeStringChar);
+
+        // Replace delimiters with snippets.
         if (escapeValue) {
+          isEscaping = true;
           source += "' +\n__e(" + escapeValue + ") +\n'";
         }
         if (evaluateValue) {
@@ -6265,31 +10769,35 @@
         }
         index = offset + match.length;
 
-        // the JS engine embedded in Adobe products requires returning the `match`
-        // string in order to produce the correct `offset` value
+        // The JS engine embedded in Adobe products requires returning the `match`
+        // string in order to produce the correct `offset` value.
         return match;
       });
 
       source += "';\n";
 
-      // if `variable` is not specified, wrap a with-statement around the generated
-      // code to add the data object to the top of the scope chain
-      var variable = options.variable,
-          hasVariable = variable;
-
-      if (!hasVariable) {
-        variable = 'obj';
-        source = 'with (' + variable + ') {\n' + source + '\n}\n';
-      }
-      // cleanup code by stripping empty strings
+      // If `variable` is not specified wrap a with-statement around the generated
+      // code to add the data object to the top of the scope chain.
+      var variable = options.variable;
+      if (!variable) {
+        source = 'with (obj) {\n' + source + '\n}\n';
+      }
+      // Cleanup code by stripping empty strings.
       source = (isEvaluating ? source.replace(reEmptyStringLeading, '') : source)
         .replace(reEmptyStringMiddle, '$1')
         .replace(reEmptyStringTrailing, '$1;');
 
-      // frame code as the function body
-      source = 'function(' + variable + ') {\n' +
-        (hasVariable ? '' : variable + ' || (' + variable + ' = {});\n') +
-        "var __t, __p = '', __e = _.escape" +
+      // Frame code as the function body.
+      source = 'function(' + (variable || 'obj') + ') {\n' +
+        (variable
+          ? ''
+          : 'obj || (obj = {});\n'
+        ) +
+        "var __t, __p = ''" +
+        (isEscaping
+           ? ', __e = _.escape'
+           : ''
+        ) +
         (isEvaluating
           ? ', __j = Array.prototype.join;\n' +
             "function print() { __p += __j.call(arguments, '') }\n"
@@ -6298,86 +10806,776 @@
         source +
         'return __p\n}';
 
-      // Use a sourceURL for easier debugging.
-      // http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl
-      var sourceURL = '\n/*\n//# sourceURL=' + (options.sourceURL || '/lodash/template/source[' + (templateCounter++) + ']') + '\n*/';
-
-      try {
-        var result = Function(importsKeys, 'return ' + source + sourceURL).apply(undefined, importsValues);
-      } catch(e) {
-        e.source = source;
-        throw e;
-      }
-      if (data) {
-        return result(data);
-      }
-      // provide the compiled function's source by its `toString` method, in
-      // supported environments, or the `source` property as a convenience for
-      // inlining compiled templates during the build process
+      var result = attempt(function() {
+        return Function(importsKeys, sourceURL + 'return ' + source).apply(undefined, importsValues);
+      });
+
+      // Provide the compiled function's source by its `toString` method or
+      // the `source` property as a convenience for inlining compiled templates.
       result.source = source;
-      return result;
-    }
-
-    /**
-     * Executes the callback `n` times, returning an array of the results
-     * of each callback execution. The callback is bound to `thisArg` and invoked
-     * with one argument; (index).
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {number} n The number of times to execute the callback.
-     * @param {Function} callback The function called per iteration.
-     * @param {*} [thisArg] The `this` binding of `callback`.
-     * @returns {Array} Returns an array of the results of each `callback` execution.
-     * @example
-     *
-     * var diceRolls = _.times(3, _.partial(_.random, 1, 6));
-     * // => [3, 6, 4]
-     *
-     * _.times(3, function(n) { mage.castSpell(n); });
-     * // => calls `mage.castSpell(n)` three times, passing `n` of `0`, `1`, and `2` respectively
-     *
-     * _.times(3, function(n) { this.cast(n); }, mage);
-     * // => also calls `mage.castSpell(n)` three times
-     */
-    function times(n, callback, thisArg) {
-      n = (n = +n) > -1 ? n : 0;
-      var index = -1,
-          result = Array(n);
-
-      callback = baseCreateCallback(callback, thisArg, 1);
-      while (++index < n) {
-        result[index] = callback(index);
+      if (isError(result)) {
+        throw result;
       }
       return result;
     }
 
     /**
-     * The inverse of `_.escape` this method converts the HTML entities
-     * `&amp;`, `&lt;`, `&gt;`, `&quot;`, and `&#39;` in `string` to their
+     * Removes leading and trailing whitespace or specified characters from `string`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to trim.
+     * @param {string} [chars=whitespace] The characters to trim.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {string} Returns the trimmed string.
+     * @example
+     *
+     * _.trim('  abc  ');
+     * // => 'abc'
+     *
+     * _.trim('-_-abc-_-', '_-');
+     * // => 'abc'
+     *
+     * _.map(['  foo  ', '  bar  '], _.trim);
+     * // => ['foo', 'bar']
+     */
+    function trim(string, chars, guard) {
+      var value = string;
+      string = baseToString(string);
+      if (!string) {
+        return string;
+      }
+      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
+        return string.slice(trimmedLeftIndex(string), trimmedRightIndex(string) + 1);
+      }
+      chars = (chars + '');
+      return string.slice(charsLeftIndex(string, chars), charsRightIndex(string, chars) + 1);
+    }
+
+    /**
+     * Removes leading whitespace or specified characters from `string`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to trim.
+     * @param {string} [chars=whitespace] The characters to trim.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {string} Returns the trimmed string.
+     * @example
+     *
+     * _.trimLeft('  abc  ');
+     * // => 'abc  '
+     *
+     * _.trimLeft('-_-abc-_-', '_-');
+     * // => 'abc-_-'
+     */
+    function trimLeft(string, chars, guard) {
+      var value = string;
+      string = baseToString(string);
+      if (!string) {
+        return string;
+      }
+      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
+        return string.slice(trimmedLeftIndex(string));
+      }
+      return string.slice(charsLeftIndex(string, (chars + '')));
+    }
+
+    /**
+     * Removes trailing whitespace or specified characters from `string`.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to trim.
+     * @param {string} [chars=whitespace] The characters to trim.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {string} Returns the trimmed string.
+     * @example
+     *
+     * _.trimRight('  abc  ');
+     * // => '  abc'
+     *
+     * _.trimRight('-_-abc-_-', '_-');
+     * // => '-_-abc'
+     */
+    function trimRight(string, chars, guard) {
+      var value = string;
+      string = baseToString(string);
+      if (!string) {
+        return string;
+      }
+      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
+        return string.slice(0, trimmedRightIndex(string) + 1);
+      }
+      return string.slice(0, charsRightIndex(string, (chars + '')) + 1);
+    }
+
+    /**
+     * Truncates `string` if it's longer than the given maximum string length.
+     * The last characters of the truncated string are replaced with the omission
+     * string which defaults to "...".
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to truncate.
+     * @param {Object|number} [options] The options object or maximum string length.
+     * @param {number} [options.length=30] The maximum string length.
+     * @param {string} [options.omission='...'] The string to indicate text is omitted.
+     * @param {RegExp|string} [options.separator] The separator pattern to truncate to.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {string} Returns the truncated string.
+     * @example
+     *
+     * _.trunc('hi-diddly-ho there, neighborino');
+     * // => 'hi-diddly-ho there, neighbo...'
+     *
+     * _.trunc('hi-diddly-ho there, neighborino', 24);
+     * // => 'hi-diddly-ho there, n...'
+     *
+     * _.trunc('hi-diddly-ho there, neighborino', {
+     *   'length': 24,
+     *   'separator': ' '
+     * });
+     * // => 'hi-diddly-ho there,...'
+     *
+     * _.trunc('hi-diddly-ho there, neighborino', {
+     *   'length': 24,
+     *   'separator': /,? +/
+     * });
+     * // => 'hi-diddly-ho there...'
+     *
+     * _.trunc('hi-diddly-ho there, neighborino', {
+     *   'omission': ' [...]'
+     * });
+     * // => 'hi-diddly-ho there, neig [...]'
+     */
+    function trunc(string, options, guard) {
+      if (guard && isIterateeCall(string, options, guard)) {
+        options = undefined;
+      }
+      var length = DEFAULT_TRUNC_LENGTH,
+          omission = DEFAULT_TRUNC_OMISSION;
+
+      if (options != null) {
+        if (isObject(options)) {
+          var separator = 'separator' in options ? options.separator : separator;
+          length = 'length' in options ? (+options.length || 0) : length;
+          omission = 'omission' in options ? baseToString(options.omission) : omission;
+        } else {
+          length = +options || 0;
+        }
+      }
+      string = baseToString(string);
+      if (length >= string.length) {
+        return string;
+      }
+      var end = length - omission.length;
+      if (end < 1) {
+        return omission;
+      }
+      var result = string.slice(0, end);
+      if (separator == null) {
+        return result + omission;
+      }
+      if (isRegExp(separator)) {
+        if (string.slice(end).search(separator)) {
+          var match,
+              newEnd,
+              substring = string.slice(0, end);
+
+          if (!separator.global) {
+            separator = RegExp(separator.source, (reFlags.exec(separator) || '') + 'g');
+          }
+          separator.lastIndex = 0;
+          while ((match = separator.exec(substring))) {
+            newEnd = match.index;
+          }
+          result = result.slice(0, newEnd == null ? end : newEnd);
+        }
+      } else if (string.indexOf(separator, end) != end) {
+        var index = result.lastIndexOf(separator);
+        if (index > -1) {
+          result = result.slice(0, index);
+        }
+      }
+      return result + omission;
+    }
+
+    /**
+     * The inverse of `_.escape`; this method converts the HTML entities
+     * `&amp;`, `&lt;`, `&gt;`, `&quot;`, `&#39;`, and `&#96;` in `string` to their
      * corresponding characters.
      *
-     * @static
-     * @memberOf _
-     * @category Utilities
-     * @param {string} string The string to unescape.
+     * **Note:** No other HTML entities are unescaped. To unescape additional HTML
+     * entities use a third-party library like [_he_](https://mths.be/he).
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to unescape.
      * @returns {string} Returns the unescaped string.
      * @example
      *
-     * _.unescape('Fred, Barney &amp; Pebbles');
-     * // => 'Fred, Barney & Pebbles'
+     * _.unescape('fred, barney, &amp; pebbles');
+     * // => 'fred, barney, & pebbles'
      */
     function unescape(string) {
-      return string == null ? '' : String(string).replace(reEscapedHtml, unescapeHtmlChar);
-    }
-
-    /**
-     * Generates a unique ID. If `prefix` is provided the ID will be appended to it.
-     *
-     * @static
-     * @memberOf _
-     * @category Utilities
+      string = baseToString(string);
+      return (string && reHasEscapedHtml.test(string))
+        ? string.replace(reEscapedHtml, unescapeHtmlChar)
+        : string;
+    }
+
+    /**
+     * Splits `string` into an array of its words.
+     *
+     * @static
+     * @memberOf _
+     * @category String
+     * @param {string} [string=''] The string to inspect.
+     * @param {RegExp|string} [pattern] The pattern to match words.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Array} Returns the words of `string`.
+     * @example
+     *
+     * _.words('fred, barney, & pebbles');
+     * // => ['fred', 'barney', 'pebbles']
+     *
+     * _.words('fred, barney, & pebbles', /[^, ]+/g);
+     * // => ['fred', 'barney', '&', 'pebbles']
+     */
+    function words(string, pattern, guard) {
+      if (guard && isIterateeCall(string, pattern, guard)) {
+        pattern = undefined;
+      }
+      string = baseToString(string);
+      return string.match(pattern || reWords) || [];
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Attempts to invoke `func`, returning either the result or the caught error
+     * object. Any additional arguments are provided to `func` when it's invoked.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Function} func The function to attempt.
+     * @returns {*} Returns the `func` result or error object.
+     * @example
+     *
+     * // avoid throwing errors for invalid selectors
+     * var elements = _.attempt(function(selector) {
+     *   return document.querySelectorAll(selector);
+     * }, '>_>');
+     *
+     * if (_.isError(elements)) {
+     *   elements = [];
+     * }
+     */
+    var attempt = restParam(function(func, args) {
+      try {
+        return func.apply(undefined, args);
+      } catch(e) {
+        return isError(e) ? e : new Error(e);
+      }
+    });
+
+    /**
+     * Creates a function that invokes `func` with the `this` binding of `thisArg`
+     * and arguments of the created function. If `func` is a property name the
+     * created callback returns the property value for a given element. If `func`
+     * is an object the created callback returns `true` for elements that contain
+     * the equivalent object properties, otherwise it returns `false`.
+     *
+     * @static
+     * @memberOf _
+     * @alias iteratee
+     * @category Utility
+     * @param {*} [func=_.identity] The value to convert to a callback.
+     * @param {*} [thisArg] The `this` binding of `func`.
+     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
+     * @returns {Function} Returns the callback.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 40 }
+     * ];
+     *
+     * // wrap to create custom callback shorthands
+     * _.callback = _.wrap(_.callback, function(callback, func, thisArg) {
+     *   var match = /^(.+?)__([gl]t)(.+)$/.exec(func);
+     *   if (!match) {
+     *     return callback(func, thisArg);
+     *   }
+     *   return function(object) {
+     *     return match[2] == 'gt'
+     *       ? object[match[1]] > match[3]
+     *       : object[match[1]] < match[3];
+     *   };
+     * });
+     *
+     * _.filter(users, 'age__gt36');
+     * // => [{ 'user': 'fred', 'age': 40 }]
+     */
+    function callback(func, thisArg, guard) {
+      if (guard && isIterateeCall(func, thisArg, guard)) {
+        thisArg = undefined;
+      }
+      return isObjectLike(func)
+        ? matches(func)
+        : baseCallback(func, thisArg);
+    }
+
+    /**
+     * Creates a function that returns `value`.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {*} value The value to return from the new function.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var object = { 'user': 'fred' };
+     * var getter = _.constant(object);
+     *
+     * getter() === object;
+     * // => true
+     */
+    function constant(value) {
+      return function() {
+        return value;
+      };
+    }
+
+    /**
+     * This method returns the first argument provided to it.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {*} value Any value.
+     * @returns {*} Returns `value`.
+     * @example
+     *
+     * var object = { 'user': 'fred' };
+     *
+     * _.identity(object) === object;
+     * // => true
+     */
+    function identity(value) {
+      return value;
+    }
+
+    /**
+     * Creates a function that performs a deep comparison between a given object
+     * and `source`, returning `true` if the given object has equivalent property
+     * values, else `false`.
+     *
+     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
+     * numbers, `Object` objects, regexes, and strings. Objects are compared by
+     * their own, not inherited, enumerable properties. For comparing a single
+     * own or inherited property value see `_.matchesProperty`.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Object} source The object of property values to match.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36, 'active': true },
+     *   { 'user': 'fred',   'age': 40, 'active': false }
+     * ];
+     *
+     * _.filter(users, _.matches({ 'age': 40, 'active': false }));
+     * // => [{ 'user': 'fred', 'age': 40, 'active': false }]
+     */
+    function matches(source) {
+      return baseMatches(baseClone(source, true));
+    }
+
+    /**
+     * Creates a function that compares the property value of `path` on a given
+     * object to `value`.
+     *
+     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
+     * numbers, `Object` objects, regexes, and strings. Objects are compared by
+     * their own, not inherited, enumerable properties.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Array|string} path The path of the property to get.
+     * @param {*} srcValue The value to match.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var users = [
+     *   { 'user': 'barney' },
+     *   { 'user': 'fred' }
+     * ];
+     *
+     * _.find(users, _.matchesProperty('user', 'fred'));
+     * // => { 'user': 'fred' }
+     */
+    function matchesProperty(path, srcValue) {
+      return baseMatchesProperty(path, baseClone(srcValue, true));
+    }
+
+    /**
+     * Creates a function that invokes the method at `path` on a given object.
+     * Any additional arguments are provided to the invoked method.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Array|string} path The path of the method to invoke.
+     * @param {...*} [args] The arguments to invoke the method with.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var objects = [
+     *   { 'a': { 'b': { 'c': _.constant(2) } } },
+     *   { 'a': { 'b': { 'c': _.constant(1) } } }
+     * ];
+     *
+     * _.map(objects, _.method('a.b.c'));
+     * // => [2, 1]
+     *
+     * _.invoke(_.sortBy(objects, _.method(['a', 'b', 'c'])), 'a.b.c');
+     * // => [1, 2]
+     */
+    var method = restParam(function(path, args) {
+      return function(object) {
+        return invokePath(object, path, args);
+      };
+    });
+
+    /**
+     * The opposite of `_.method`; this method creates a function that invokes
+     * the method at a given path on `object`. Any additional arguments are
+     * provided to the invoked method.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Object} object The object to query.
+     * @param {...*} [args] The arguments to invoke the method with.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var array = _.times(3, _.constant),
+     *     object = { 'a': array, 'b': array, 'c': array };
+     *
+     * _.map(['a[2]', 'c[0]'], _.methodOf(object));
+     * // => [2, 0]
+     *
+     * _.map([['a', '2'], ['c', '0']], _.methodOf(object));
+     * // => [2, 0]
+     */
+    var methodOf = restParam(function(object, args) {
+      return function(path) {
+        return invokePath(object, path, args);
+      };
+    });
+
+    /**
+     * Adds all own enumerable function properties of a source object to the
+     * destination object. If `object` is a function then methods are added to
+     * its prototype as well.
+     *
+     * **Note:** Use `_.runInContext` to create a pristine `lodash` function to
+     * avoid conflicts caused by modifying the original.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Function|Object} [object=lodash] The destination object.
+     * @param {Object} source The object of functions to add.
+     * @param {Object} [options] The options object.
+     * @param {boolean} [options.chain=true] Specify whether the functions added
+     *  are chainable.
+     * @returns {Function|Object} Returns `object`.
+     * @example
+     *
+     * function vowels(string) {
+     *   return _.filter(string, function(v) {
+     *     return /[aeiou]/i.test(v);
+     *   });
+     * }
+     *
+     * _.mixin({ 'vowels': vowels });
+     * _.vowels('fred');
+     * // => ['e']
+     *
+     * _('fred').vowels().value();
+     * // => ['e']
+     *
+     * _.mixin({ 'vowels': vowels }, { 'chain': false });
+     * _('fred').vowels();
+     * // => ['e']
+     */
+    function mixin(object, source, options) {
+      if (options == null) {
+        var isObj = isObject(source),
+            props = isObj ? keys(source) : undefined,
+            methodNames = (props && props.length) ? baseFunctions(source, props) : undefined;
+
+        if (!(methodNames ? methodNames.length : isObj)) {
+          methodNames = false;
+          options = source;
+          source = object;
+          object = this;
+        }
+      }
+      if (!methodNames) {
+        methodNames = baseFunctions(source, keys(source));
+      }
+      var chain = true,
+          index = -1,
+          isFunc = isFunction(object),
+          length = methodNames.length;
+
+      if (options === false) {
+        chain = false;
+      } else if (isObject(options) && 'chain' in options) {
+        chain = options.chain;
+      }
+      while (++index < length) {
+        var methodName = methodNames[index],
+            func = source[methodName];
+
+        object[methodName] = func;
+        if (isFunc) {
+          object.prototype[methodName] = (function(func) {
+            return function() {
+              var chainAll = this.__chain__;
+              if (chain || chainAll) {
+                var result = object(this.__wrapped__),
+                    actions = result.__actions__ = arrayCopy(this.__actions__);
+
+                actions.push({ 'func': func, 'args': arguments, 'thisArg': object });
+                result.__chain__ = chainAll;
+                return result;
+              }
+              return func.apply(object, arrayPush([this.value()], arguments));
+            };
+          }(func));
+        }
+      }
+      return object;
+    }
+
+    /**
+     * Reverts the `_` variable to its previous value and returns a reference to
+     * the `lodash` function.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @returns {Function} Returns the `lodash` function.
+     * @example
+     *
+     * var lodash = _.noConflict();
+     */
+    function noConflict() {
+      root._ = oldDash;
+      return this;
+    }
+
+    /**
+     * A no-operation function that returns `undefined` regardless of the
+     * arguments it receives.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @example
+     *
+     * var object = { 'user': 'fred' };
+     *
+     * _.noop(object) === undefined;
+     * // => true
+     */
+    function noop() {
+      // No operation performed.
+    }
+
+    /**
+     * Creates a function that returns the property value at `path` on a
+     * given object.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Array|string} path The path of the property to get.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var objects = [
+     *   { 'a': { 'b': { 'c': 2 } } },
+     *   { 'a': { 'b': { 'c': 1 } } }
+     * ];
+     *
+     * _.map(objects, _.property('a.b.c'));
+     * // => [2, 1]
+     *
+     * _.pluck(_.sortBy(objects, _.property(['a', 'b', 'c'])), 'a.b.c');
+     * // => [1, 2]
+     */
+    function property(path) {
+      return isKey(path) ? baseProperty(path) : basePropertyDeep(path);
+    }
+
+    /**
+     * The opposite of `_.property`; this method creates a function that returns
+     * the property value at a given path on `object`.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Object} object The object to query.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var array = [0, 1, 2],
+     *     object = { 'a': array, 'b': array, 'c': array };
+     *
+     * _.map(['a[2]', 'c[0]'], _.propertyOf(object));
+     * // => [2, 0]
+     *
+     * _.map([['a', '2'], ['c', '0']], _.propertyOf(object));
+     * // => [2, 0]
+     */
+    function propertyOf(object) {
+      return function(path) {
+        return baseGet(object, toPath(path), (path + ''));
+      };
+    }
+
+    /**
+     * Creates an array of numbers (positive and/or negative) progressing from
+     * `start` up to, but not including, `end`. If `end` is not specified it's
+     * set to `start` with `start` then set to `0`. If `end` is less than `start`
+     * a zero-length range is created unless a negative `step` is specified.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {number} [start=0] The start of the range.
+     * @param {number} end The end of the range.
+     * @param {number} [step=1] The value to increment or decrement by.
+     * @returns {Array} Returns the new array of numbers.
+     * @example
+     *
+     * _.range(4);
+     * // => [0, 1, 2, 3]
+     *
+     * _.range(1, 5);
+     * // => [1, 2, 3, 4]
+     *
+     * _.range(0, 20, 5);
+     * // => [0, 5, 10, 15]
+     *
+     * _.range(0, -4, -1);
+     * // => [0, -1, -2, -3]
+     *
+     * _.range(1, 4, 0);
+     * // => [1, 1, 1]
+     *
+     * _.range(0);
+     * // => []
+     */
+    function range(start, end, step) {
+      if (step && isIterateeCall(start, end, step)) {
+        end = step = undefined;
+      }
+      start = +start || 0;
+      step = step == null ? 1 : (+step || 0);
+
+      if (end == null) {
+        end = start;
+        start = 0;
+      } else {
+        end = +end || 0;
+      }
+      // Use `Array(length)` so engines like Chakra and V8 avoid slower modes.
+      // See https://youtu.be/XAqIpGU8ZZk#t=17m25s for more details.
+      var index = -1,
+          length = nativeMax(nativeCeil((end - start) / (step || 1)), 0),
+          result = Array(length);
+
+      while (++index < length) {
+        result[index] = start;
+        start += step;
+      }
+      return result;
+    }
+
+    /**
+     * Invokes the iteratee function `n` times, returning an array of the results
+     * of each invocation. The `iteratee` is bound to `thisArg` and invoked with
+     * one argument; (index).
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {number} n The number of times to invoke `iteratee`.
+     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {Array} Returns the array of results.
+     * @example
+     *
+     * var diceRolls = _.times(3, _.partial(_.random, 1, 6, false));
+     * // => [3, 6, 4]
+     *
+     * _.times(3, function(n) {
+     *   mage.castSpell(n);
+     * });
+     * // => invokes `mage.castSpell(n)` three times with `n` of `0`, `1`, and `2`
+     *
+     * _.times(3, function(n) {
+     *   this.cast(n);
+     * }, mage);
+     * // => also invokes `mage.castSpell(n)` three times
+     */
+    function times(n, iteratee, thisArg) {
+      n = nativeFloor(n);
+
+      // Exit early to avoid a JSC JIT bug in Safari 8
+      // where `Array(0)` is treated as `Array(1)`.
+      if (n < 1 || !nativeIsFinite(n)) {
+        return [];
+      }
+      var index = -1,
+          result = Array(nativeMin(n, MAX_ARRAY_LENGTH));
+
+      iteratee = bindCallback(iteratee, thisArg, 1);
+      while (++index < n) {
+        if (index < MAX_ARRAY_LENGTH) {
+          result[index] = iteratee(index);
+        } else {
+          iteratee(index);
+        }
+      }
+      return result;
+    }
+
+    /**
+     * Generates a unique ID. If `prefix` is provided the ID is appended to it.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
      * @param {string} [prefix] The value to prefix the ID with.
      * @returns {string} Returns the unique ID.
      * @example
@@ -6390,153 +11588,292 @@
      */
     function uniqueId(prefix) {
       var id = ++idCounter;
-      return String(prefix == null ? '' : prefix) + id;
-    }
-
-    /*--------------------------------------------------------------------------*/
-
-    /**
-     * Creates a `lodash` object that wraps the given value with explicit
-     * method chaining enabled.
-     *
-     * @static
-     * @memberOf _
-     * @category Chaining
-     * @param {*} value The value to wrap.
-     * @returns {Object} Returns the wrapper object.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney',  'age': 36 },
-     *   { 'name': 'fred',    'age': 40 },
-     *   { 'name': 'pebbles', 'age': 1 }
+      return baseToString(prefix) + id;
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    /**
+     * Adds two numbers.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {number} augend The first number to add.
+     * @param {number} addend The second number to add.
+     * @returns {number} Returns the sum.
+     * @example
+     *
+     * _.add(6, 4);
+     * // => 10
+     */
+    function add(augend, addend) {
+      return (+augend || 0) + (+addend || 0);
+    }
+
+    /**
+     * Calculates `n` rounded up to `precision`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {number} n The number to round up.
+     * @param {number} [precision=0] The precision to round up to.
+     * @returns {number} Returns the rounded up number.
+     * @example
+     *
+     * _.ceil(4.006);
+     * // => 5
+     *
+     * _.ceil(6.004, 2);
+     * // => 6.01
+     *
+     * _.ceil(6040, -2);
+     * // => 6100
+     */
+    var ceil = createRound('ceil');
+
+    /**
+     * Calculates `n` rounded down to `precision`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {number} n The number to round down.
+     * @param {number} [precision=0] The precision to round down to.
+     * @returns {number} Returns the rounded down number.
+     * @example
+     *
+     * _.floor(4.006);
+     * // => 4
+     *
+     * _.floor(0.046, 2);
+     * // => 0.04
+     *
+     * _.floor(4060, -2);
+     * // => 4000
+     */
+    var floor = createRound('floor');
+
+    /**
+     * Gets the maximum value of `collection`. If `collection` is empty or falsey
+     * `-Infinity` is returned. If an iteratee function is provided it's invoked
+     * for each value in `collection` to generate the criterion by which the value
+     * is ranked. The `iteratee` is bound to `thisArg` and invoked with three
+     * arguments: (value, index, collection).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {*} Returns the maximum value.
+     * @example
+     *
+     * _.max([4, 2, 8, 6]);
+     * // => 8
+     *
+     * _.max([]);
+     * // => -Infinity
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 40 }
      * ];
      *
-     * var youngest = _.chain(characters)
-     *     .sortBy('age')
-     *     .map(function(chr) { return chr.name + ' is ' + chr.age; })
-     *     .first()
-     *     .value();
-     * // => 'pebbles is 1'
-     */
-    function chain(value) {
-      value = new lodashWrapper(value);
-      value.__chain__ = true;
-      return value;
-    }
-
-    /**
-     * Invokes `interceptor` with the `value` as the first argument and then
-     * returns `value`. The purpose of this method is to "tap into" a method
-     * chain in order to perform operations on intermediate results within
-     * the chain.
-     *
-     * @static
-     * @memberOf _
-     * @category Chaining
-     * @param {*} value The value to provide to `interceptor`.
-     * @param {Function} interceptor The function to invoke.
-     * @returns {*} Returns `value`.
-     * @example
-     *
-     * _([1, 2, 3, 4])
-     *  .tap(function(array) { array.pop(); })
-     *  .reverse()
-     *  .value();
-     * // => [3, 2, 1]
-     */
-    function tap(value, interceptor) {
-      interceptor(value);
-      return value;
-    }
-
-    /**
-     * Enables explicit method chaining on the wrapper object.
-     *
-     * @name chain
-     * @memberOf _
-     * @category Chaining
-     * @returns {*} Returns the wrapper object.
-     * @example
-     *
-     * var characters = [
-     *   { 'name': 'barney', 'age': 36 },
-     *   { 'name': 'fred',   'age': 40 }
+     * _.max(users, function(chr) {
+     *   return chr.age;
+     * });
+     * // => { 'user': 'fred', 'age': 40 }
+     *
+     * // using the `_.property` callback shorthand
+     * _.max(users, 'age');
+     * // => { 'user': 'fred', 'age': 40 }
+     */
+    var max = createExtremum(gt, NEGATIVE_INFINITY);
+
+    /**
+     * Gets the minimum value of `collection`. If `collection` is empty or falsey
+     * `Infinity` is returned. If an iteratee function is provided it's invoked
+     * for each value in `collection` to generate the criterion by which the value
+     * is ranked. The `iteratee` is bound to `thisArg` and invoked with three
+     * arguments: (value, index, collection).
+     *
+     * If a property name is provided for `iteratee` the created `_.property`
+     * style callback returns the property value of the given element.
+     *
+     * If a value is also provided for `thisArg` the created `_.matchesProperty`
+     * style callback returns `true` for elements that have a matching property
+     * value, else `false`.
+     *
+     * If an object is provided for `iteratee` the created `_.matches` style
+     * callback returns `true` for elements that have the properties of the given
+     * object, else `false`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {*} Returns the minimum value.
+     * @example
+     *
+     * _.min([4, 2, 8, 6]);
+     * // => 2
+     *
+     * _.min([]);
+     * // => Infinity
+     *
+     * var users = [
+     *   { 'user': 'barney', 'age': 36 },
+     *   { 'user': 'fred',   'age': 40 }
      * ];
      *
-     * // without explicit chaining
-     * _(characters).first();
-     * // => { 'name': 'barney', 'age': 36 }
-     *
-     * // with explicit chaining
-     * _(characters).chain()
-     *   .first()
-     *   .pick('age')
-     *   .value();
-     * // => { 'age': 36 }
-     */
-    function wrapperChain() {
-      this.__chain__ = true;
-      return this;
-    }
-
-    /**
-     * Produces the `toString` result of the wrapped value.
-     *
-     * @name toString
-     * @memberOf _
-     * @category Chaining
-     * @returns {string} Returns the string result.
-     * @example
-     *
-     * _([1, 2, 3]).toString();
-     * // => '1,2,3'
-     */
-    function wrapperToString() {
-      return String(this.__wrapped__);
-    }
-
-    /**
-     * Extracts the wrapped value.
-     *
-     * @name valueOf
-     * @memberOf _
-     * @alias value
-     * @category Chaining
-     * @returns {*} Returns the wrapped value.
-     * @example
-     *
-     * _([1, 2, 3]).valueOf();
-     * // => [1, 2, 3]
-     */
-    function wrapperValueOf() {
-      return this.__wrapped__;
-    }
-
-    /*--------------------------------------------------------------------------*/
-
-    // add functions that return wrapped values when chaining
+     * _.min(users, function(chr) {
+     *   return chr.age;
+     * });
+     * // => { 'user': 'barney', 'age': 36 }
+     *
+     * // using the `_.property` callback shorthand
+     * _.min(users, 'age');
+     * // => { 'user': 'barney', 'age': 36 }
+     */
+    var min = createExtremum(lt, POSITIVE_INFINITY);
+
+    /**
+     * Calculates `n` rounded to `precision`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {number} n The number to round.
+     * @param {number} [precision=0] The precision to round to.
+     * @returns {number} Returns the rounded number.
+     * @example
+     *
+     * _.round(4.006);
+     * // => 4
+     *
+     * _.round(4.006, 2);
+     * // => 4.01
+     *
+     * _.round(4060, -2);
+     * // => 4100
+     */
+    var round = createRound('round');
+
+    /**
+     * Gets the sum of the values in `collection`.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {Array|Object|string} collection The collection to iterate over.
+     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
+     * @param {*} [thisArg] The `this` binding of `iteratee`.
+     * @returns {number} Returns the sum.
+     * @example
+     *
+     * _.sum([4, 6]);
+     * // => 10
+     *
+     * _.sum({ 'a': 4, 'b': 6 });
+     * // => 10
+     *
+     * var objects = [
+     *   { 'n': 4 },
+     *   { 'n': 6 }
+     * ];
+     *
+     * _.sum(objects, function(object) {
+     *   return object.n;
+     * });
+     * // => 10
+     *
+     * // using the `_.property` callback shorthand
+     * _.sum(objects, 'n');
+     * // => 10
+     */
+    function sum(collection, iteratee, thisArg) {
+      if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
+        iteratee = undefined;
+      }
+      iteratee = getCallback(iteratee, thisArg, 3);
+      return iteratee.length == 1
+        ? arraySum(isArray(collection) ? collection : toIterable(collection), iteratee)
+        : baseSum(collection, iteratee);
+    }
+
+    /*------------------------------------------------------------------------*/
+
+    // Ensure wrappers are instances of `baseLodash`.
+    lodash.prototype = baseLodash.prototype;
+
+    LodashWrapper.prototype = baseCreate(baseLodash.prototype);
+    LodashWrapper.prototype.constructor = LodashWrapper;
+
+    LazyWrapper.prototype = baseCreate(baseLodash.prototype);
+    LazyWrapper.prototype.constructor = LazyWrapper;
+
+    // Add functions to the `Map` cache.
+    MapCache.prototype['delete'] = mapDelete;
+    MapCache.prototype.get = mapGet;
+    MapCache.prototype.has = mapHas;
+    MapCache.prototype.set = mapSet;
+
+    // Add functions to the `Set` cache.
+    SetCache.prototype.push = cachePush;
+
+    // Assign cache to `_.memoize`.
+    memoize.Cache = MapCache;
+
+    // Add functions that return wrapped values when chaining.
     lodash.after = after;
+    lodash.ary = ary;
     lodash.assign = assign;
     lodash.at = at;
+    lodash.before = before;
     lodash.bind = bind;
     lodash.bindAll = bindAll;
     lodash.bindKey = bindKey;
+    lodash.callback = callback;
     lodash.chain = chain;
+    lodash.chunk = chunk;
     lodash.compact = compact;
-    lodash.compose = compose;
     lodash.constant = constant;
     lodash.countBy = countBy;
     lodash.create = create;
-    lodash.createCallback = createCallback;
     lodash.curry = curry;
+    lodash.curryRight = curryRight;
     lodash.debounce = debounce;
     lodash.defaults = defaults;
+    lodash.defaultsDeep = defaultsDeep;
     lodash.defer = defer;
     lodash.delay = delay;
     lodash.difference = difference;
+    lodash.drop = drop;
+    lodash.dropRight = dropRight;
+    lodash.dropRightWhile = dropRightWhile;
+    lodash.dropWhile = dropWhile;
+    lodash.fill = fill;
     lodash.filter = filter;
     lodash.flatten = flatten;
+    lodash.flattenDeep = flattenDeep;
+    lodash.flow = flow;
+    lodash.flowRight = flowRight;
     lodash.forEach = forEach;
     lodash.forEachRight = forEachRight;
     lodash.forIn = forIn;
@@ -6551,65 +11888,100 @@
     lodash.invert = invert;
     lodash.invoke = invoke;
     lodash.keys = keys;
+    lodash.keysIn = keysIn;
     lodash.map = map;
+    lodash.mapKeys = mapKeys;
     lodash.mapValues = mapValues;
-    lodash.max = max;
+    lodash.matches = matches;
+    lodash.matchesProperty = matchesProperty;
     lodash.memoize = memoize;
     lodash.merge = merge;
-    lodash.min = min;
+    lodash.method = method;
+    lodash.methodOf = methodOf;
+    lodash.mixin = mixin;
+    lodash.modArgs = modArgs;
+    lodash.negate = negate;
     lodash.omit = omit;
     lodash.once = once;
     lodash.pairs = pairs;
     lodash.partial = partial;
     lodash.partialRight = partialRight;
+    lodash.partition = partition;
     lodash.pick = pick;
     lodash.pluck = pluck;
     lodash.property = property;
+    lodash.propertyOf = propertyOf;
     lodash.pull = pull;
+    lodash.pullAt = pullAt;
     lodash.range = range;
+    lodash.rearg = rearg;
     lodash.reject = reject;
     lodash.remove = remove;
     lodash.rest = rest;
+    lodash.restParam = restParam;
+    lodash.set = set;
     lodash.shuffle = shuffle;
+    lodash.slice = slice;
     lodash.sortBy = sortBy;
+    lodash.sortByAll = sortByAll;
+    lodash.sortByOrder = sortByOrder;
+    lodash.spread = spread;
+    lodash.take = take;
+    lodash.takeRight = takeRight;
+    lodash.takeRightWhile = takeRightWhile;
+    lodash.takeWhile = takeWhile;
     lodash.tap = tap;
     lodash.throttle = throttle;
+    lodash.thru = thru;
     lodash.times = times;
     lodash.toArray = toArray;
+    lodash.toPlainObject = toPlainObject;
     lodash.transform = transform;
     lodash.union = union;
     lodash.uniq = uniq;
+    lodash.unzip = unzip;
+    lodash.unzipWith = unzipWith;
     lodash.values = values;
+    lodash.valuesIn = valuesIn;
     lodash.where = where;
     lodash.without = without;
     lodash.wrap = wrap;
     lodash.xor = xor;
     lodash.zip = zip;
     lodash.zipObject = zipObject;
-
-    // add aliases
+    lodash.zipWith = zipWith;
+
+    // Add aliases.
+    lodash.backflow = flowRight;
     lodash.collect = map;
-    lodash.drop = rest;
+    lodash.compose = flowRight;
     lodash.each = forEach;
     lodash.eachRight = forEachRight;
     lodash.extend = assign;
+    lodash.iteratee = callback;
     lodash.methods = functions;
     lodash.object = zipObject;
     lodash.select = filter;
     lodash.tail = rest;
     lodash.unique = uniq;
-    lodash.unzip = zip;
-
-    // add functions to `lodash.prototype`
-    mixin(lodash);
-
-    /*--------------------------------------------------------------------------*/
-
-    // add functions that return unwrapped values when chaining
+
+    // Add functions to `lodash.prototype`.
+    mixin(lodash, lodash);
+
+    /*------------------------------------------------------------------------*/
+
+    // Add functions that return unwrapped values when chaining.
+    lodash.add = add;
+    lodash.attempt = attempt;
+    lodash.camelCase = camelCase;
+    lodash.capitalize = capitalize;
+    lodash.ceil = ceil;
     lodash.clone = clone;
     lodash.cloneDeep = cloneDeep;
-    lodash.contains = contains;
+    lodash.deburr = deburr;
+    lodash.endsWith = endsWith;
     lodash.escape = escape;
+    lodash.escapeRegExp = escapeRegExp;
     lodash.every = every;
     lodash.find = find;
     lodash.findIndex = findIndex;
@@ -6617,9 +11989,17 @@
     lodash.findLast = findLast;
     lodash.findLastIndex = findLastIndex;
     lodash.findLastKey = findLastKey;
+    lodash.findWhere = findWhere;
+    lodash.first = first;
+    lodash.floor = floor;
+    lodash.get = get;
+    lodash.gt = gt;
+    lodash.gte = gte;
     lodash.has = has;
     lodash.identity = identity;
+    lodash.includes = includes;
     lodash.indexOf = indexOf;
+    lodash.inRange = inRange;
     lodash.isArguments = isArguments;
     lodash.isArray = isArray;
     lodash.isBoolean = isBoolean;
@@ -6627,80 +12007,95 @@
     lodash.isElement = isElement;
     lodash.isEmpty = isEmpty;
     lodash.isEqual = isEqual;
+    lodash.isError = isError;
     lodash.isFinite = isFinite;
     lodash.isFunction = isFunction;
+    lodash.isMatch = isMatch;
     lodash.isNaN = isNaN;
+    lodash.isNative = isNative;
     lodash.isNull = isNull;
     lodash.isNumber = isNumber;
     lodash.isObject = isObject;
     lodash.isPlainObject = isPlainObject;
     lodash.isRegExp = isRegExp;
     lodash.isString = isString;
+    lodash.isTypedArray = isTypedArray;
     lodash.isUndefined = isUndefined;
+    lodash.kebabCase = kebabCase;
+    lodash.last = last;
     lodash.lastIndexOf = lastIndexOf;
-    lodash.mixin = mixin;
+    lodash.lt = lt;
+    lodash.lte = lte;
+    lodash.max = max;
+    lodash.min = min;
     lodash.noConflict = noConflict;
     lodash.noop = noop;
     lodash.now = now;
+    lodash.pad = pad;
+    lodash.padLeft = padLeft;
+    lodash.padRight = padRight;
     lodash.parseInt = parseInt;
     lodash.random = random;
     lodash.reduce = reduce;
     lodash.reduceRight = reduceRight;
+    lodash.repeat = repeat;
     lodash.result = result;
+    lodash.round = round;
     lodash.runInContext = runInContext;
     lodash.size = size;
+    lodash.snakeCase = snakeCase;
     lodash.some = some;
     lodash.sortedIndex = sortedIndex;
+    lodash.sortedLastIndex = sortedLastIndex;
+    lodash.startCase = startCase;
+    lodash.startsWith = startsWith;
+    lodash.sum = sum;
     lodash.template = template;
+    lodash.trim = trim;
+    lodash.trimLeft = trimLeft;
+    lodash.trimRight = trimRight;
+    lodash.trunc = trunc;
     lodash.unescape = unescape;
     lodash.uniqueId = uniqueId;
-
-    // add aliases
+    lodash.words = words;
+
+    // Add aliases.
     lodash.all = every;
     lodash.any = some;
+    lodash.contains = includes;
+    lodash.eq = isEqual;
     lodash.detect = find;
-    lodash.findWhere = find;
     lodash.foldl = reduce;
     lodash.foldr = reduceRight;
-    lodash.include = contains;
+    lodash.head = first;
+    lodash.include = includes;
     lodash.inject = reduce;
 
-    mixin(function() {
-      var source = {}
-      forOwn(lodash, function(func, methodName) {
+    mixin(lodash, (function() {
+      var source = {};
+      baseForOwn(lodash, function(func, methodName) {
         if (!lodash.prototype[methodName]) {
           source[methodName] = func;
         }
       });
       return source;
-    }(), false);
-
-    /*--------------------------------------------------------------------------*/
-
-    // add functions capable of returning wrapped and unwrapped values when chaining
-    lodash.first = first;
-    lodash.last = last;
+    }()), false);
+
+    /*------------------------------------------------------------------------*/
+
+    // Add functions capable of returning wrapped and unwrapped values when chaining.
     lodash.sample = sample;
 
-    // add aliases
-    lodash.take = first;
-    lodash.head = first;
-
-    forOwn(lodash, function(func, methodName) {
-      var callbackable = methodName !== 'sample';
-      if (!lodash.prototype[methodName]) {
-        lodash.prototype[methodName]= function(n, guard) {
-          var chainAll = this.__chain__,
-              result = func(this.__wrapped__, n, guard);
-
-          return !chainAll && (n == null || (guard && !(callbackable && typeof n == 'function')))
-            ? result
-            : new lodashWrapper(result, chainAll);
-        };
-      }
-    });
-
-    /*--------------------------------------------------------------------------*/
+    lodash.prototype.sample = function(n) {
+      if (!this.__chain__ && n == null) {
+        return sample(this.value());
+      }
+      return this.thru(function(value) {
+        return sample(value, n);
+      });
+    };
+
+    /*------------------------------------------------------------------------*/
 
     /**
      * The semantic version number.
@@ -6709,78 +12104,249 @@
      * @memberOf _
      * @type string
      */
-    lodash.VERSION = '2.4.2';
-
-    // add "Chaining" functions to the wrapper
-    lodash.prototype.chain = wrapperChain;
-    lodash.prototype.toString = wrapperToString;
-    lodash.prototype.value = wrapperValueOf;
-    lodash.prototype.valueOf = wrapperValueOf;
-
-    // add `Array` functions that return unwrapped values
-    forEach(['join', 'pop', 'shift'], function(methodName) {
-      var func = arrayRef[methodName];
-      lodash.prototype[methodName] = function() {
-        var chainAll = this.__chain__,
-            result = func.apply(this.__wrapped__, arguments);
-
-        return chainAll
-          ? new lodashWrapper(result, chainAll)
-          : result;
+    lodash.VERSION = VERSION;
+
+    // Assign default placeholders.
+    arrayEach(['bind', 'bindKey', 'curry', 'curryRight', 'partial', 'partialRight'], function(methodName) {
+      lodash[methodName].placeholder = lodash;
+    });
+
+    // Add `LazyWrapper` methods for `_.drop` and `_.take` variants.
+    arrayEach(['drop', 'take'], function(methodName, index) {
+      LazyWrapper.prototype[methodName] = function(n) {
+        var filtered = this.__filtered__;
+        if (filtered && !index) {
+          return new LazyWrapper(this);
+        }
+        n = n == null ? 1 : nativeMax(nativeFloor(n) || 0, 0);
+
+        var result = this.clone();
+        if (filtered) {
+          result.__takeCount__ = nativeMin(result.__takeCount__, n);
+        } else {
+          result.__views__.push({ 'size': n, 'type': methodName + (result.__dir__ < 0 ? 'Right' : '') });
+        }
+        return result;
+      };
+
+      LazyWrapper.prototype[methodName + 'Right'] = function(n) {
+        return this.reverse()[methodName](n).reverse();
+      };
+    });
+
+    // Add `LazyWrapper` methods that accept an `iteratee` value.
+    arrayEach(['filter', 'map', 'takeWhile'], function(methodName, index) {
+      var type = index + 1,
+          isFilter = type != LAZY_MAP_FLAG;
+
+      LazyWrapper.prototype[methodName] = function(iteratee, thisArg) {
+        var result = this.clone();
+        result.__iteratees__.push({ 'iteratee': getCallback(iteratee, thisArg, 1), 'type': type });
+        result.__filtered__ = result.__filtered__ || isFilter;
+        return result;
+      };
+    });
+
+    // Add `LazyWrapper` methods for `_.first` and `_.last`.
+    arrayEach(['first', 'last'], function(methodName, index) {
+      var takeName = 'take' + (index ? 'Right' : '');
+
+      LazyWrapper.prototype[methodName] = function() {
+        return this[takeName](1).value()[0];
+      };
+    });
+
+    // Add `LazyWrapper` methods for `_.initial` and `_.rest`.
+    arrayEach(['initial', 'rest'], function(methodName, index) {
+      var dropName = 'drop' + (index ? '' : 'Right');
+
+      LazyWrapper.prototype[methodName] = function() {
+        return this.__filtered__ ? new LazyWrapper(this) : this[dropName](1);
+      };
+    });
+
+    // Add `LazyWrapper` methods for `_.pluck` and `_.where`.
+    arrayEach(['pluck', 'where'], function(methodName, index) {
+      var operationName = index ? 'filter' : 'map',
+          createCallback = index ? baseMatches : property;
+
+      LazyWrapper.prototype[methodName] = function(value) {
+        return this[operationName](createCallback(value));
       };
     });
 
-    // add `Array` functions that return the existing wrapped value
-    forEach(['push', 'reverse', 'sort', 'unshift'], function(methodName) {
-      var func = arrayRef[methodName];
+    LazyWrapper.prototype.compact = function() {
+      return this.filter(identity);
+    };
+
+    LazyWrapper.prototype.reject = function(predicate, thisArg) {
+      predicate = getCallback(predicate, thisArg, 1);
+      return this.filter(function(value) {
+        return !predicate(value);
+      });
+    };
+
+    LazyWrapper.prototype.slice = function(start, end) {
+      start = start == null ? 0 : (+start || 0);
+
+      var result = this;
+      if (result.__filtered__ && (start > 0 || end < 0)) {
+        return new LazyWrapper(result);
+      }
+      if (start < 0) {
+        result = result.takeRight(-start);
+      } else if (start) {
+        result = result.drop(start);
+      }
+      if (end !== undefined) {
+        end = (+end || 0);
+        result = end < 0 ? result.dropRight(-end) : result.take(end - start);
+      }
+      return result;
+    };
+
+    LazyWrapper.prototype.takeRightWhile = function(predicate, thisArg) {
+      return this.reverse().takeWhile(predicate, thisArg).reverse();
+    };
+
+    LazyWrapper.prototype.toArray = function() {
+      return this.take(POSITIVE_INFINITY);
+    };
+
+    // Add `LazyWrapper` methods to `lodash.prototype`.
+    baseForOwn(LazyWrapper.prototype, function(func, methodName) {
+      var checkIteratee = /^(?:filter|map|reject)|While$/.test(methodName),
+          retUnwrapped = /^(?:first|last)$/.test(methodName),
+          lodashFunc = lodash[retUnwrapped ? ('take' + (methodName == 'last' ? 'Right' : '')) : methodName];
+
+      if (!lodashFunc) {
+        return;
+      }
       lodash.prototype[methodName] = function() {
-        func.apply(this.__wrapped__, arguments);
-        return this;
+        var args = retUnwrapped ? [1] : arguments,
+            chainAll = this.__chain__,
+            value = this.__wrapped__,
+            isHybrid = !!this.__actions__.length,
+            isLazy = value instanceof LazyWrapper,
+            iteratee = args[0],
+            useLazy = isLazy || isArray(value);
+
+        if (useLazy && checkIteratee && typeof iteratee == 'function' && iteratee.length != 1) {
+          // Avoid lazy use if the iteratee has a "length" value other than `1`.
+          isLazy = useLazy = false;
+        }
+        var interceptor = function(value) {
+          return (retUnwrapped && chainAll)
+            ? lodashFunc(value, 1)[0]
+            : lodashFunc.apply(undefined, arrayPush([value], args));
+        };
+
+        var action = { 'func': thru, 'args': [interceptor], 'thisArg': undefined },
+            onlyLazy = isLazy && !isHybrid;
+
+        if (retUnwrapped && !chainAll) {
+          if (onlyLazy) {
+            value = value.clone();
+            value.__actions__.push(action);
+            return func.call(value);
+          }
+          return lodashFunc.call(undefined, this.value())[0];
+        }
+        if (!retUnwrapped && useLazy) {
+          value = onlyLazy ? value : new LazyWrapper(this);
+          var result = func.apply(value, args);
+          result.__actions__.push(action);
+          return new LodashWrapper(result, chainAll);
+        }
+        return this.thru(interceptor);
       };
     });
 
-    // add `Array` functions that return new wrapped values
-    forEach(['concat', 'slice', 'splice'], function(methodName) {
-      var func = arrayRef[methodName];
+    // Add `Array` and `String` methods to `lodash.prototype`.
+    arrayEach(['join', 'pop', 'push', 'replace', 'shift', 'sort', 'splice', 'split', 'unshift'], function(methodName) {
+      var func = (/^(?:replace|split)$/.test(methodName) ? stringProto : arrayProto)[methodName],
+          chainName = /^(?:push|sort|unshift)$/.test(methodName) ? 'tap' : 'thru',
+          retUnwrapped = /^(?:join|pop|replace|shift)$/.test(methodName);
+
       lodash.prototype[methodName] = function() {
-        return new lodashWrapper(func.apply(this.__wrapped__, arguments), this.__chain__);
+        var args = arguments;
+        if (retUnwrapped && !this.__chain__) {
+          return func.apply(this.value(), args);
+        }
+        return this[chainName](function(value) {
+          return func.apply(value, args);
+        });
       };
     });
 
+    // Map minified function names to their real names.
+    baseForOwn(LazyWrapper.prototype, function(func, methodName) {
+      var lodashFunc = lodash[methodName];
+      if (lodashFunc) {
+        var key = (lodashFunc.name + ''),
+            names = realNames[key] || (realNames[key] = []);
+
+        names.push({ 'name': methodName, 'func': lodashFunc });
+      }
+    });
+
+    realNames[createHybridWrapper(undefined, BIND_KEY_FLAG).name] = [{ 'name': 'wrapper', 'func': undefined }];
+
+    // Add functions to the lazy wrapper.
+    LazyWrapper.prototype.clone = lazyClone;
+    LazyWrapper.prototype.reverse = lazyReverse;
+    LazyWrapper.prototype.value = lazyValue;
+
+    // Add chaining functions to the `lodash` wrapper.
+    lodash.prototype.chain = wrapperChain;
+    lodash.prototype.commit = wrapperCommit;
+    lodash.prototype.concat = wrapperConcat;
+    lodash.prototype.plant = wrapperPlant;
+    lodash.prototype.reverse = wrapperReverse;
+    lodash.prototype.toString = wrapperToString;
+    lodash.prototype.run = lodash.prototype.toJSON = lodash.prototype.valueOf = lodash.prototype.value = wrapperValue;
+
+    // Add function aliases to the `lodash` wrapper.
+    lodash.prototype.collect = lodash.prototype.map;
+    lodash.prototype.head = lodash.prototype.first;
+    lodash.prototype.select = lodash.prototype.filter;
+    lodash.prototype.tail = lodash.prototype.rest;
+
     return lodash;
   }
 
   /*--------------------------------------------------------------------------*/
 
-  // expose Lo-Dash
+  // Export lodash.
   var _ = runInContext();
 
-  // some AMD build optimizers like r.js check for condition patterns like the following:
+  // Some AMD build optimizers like r.js check for condition patterns like the following:
   if (typeof define == 'function' && typeof define.amd == 'object' && define.amd) {
-    // Expose Lo-Dash to the global object even when an AMD loader is present in
-    // case Lo-Dash is loaded with a RequireJS shim config.
-    // See http://requirejs.org/docs/api.html#config-shim
+    // Expose lodash to the global object when an AMD loader is present to avoid
+    // errors in cases where lodash is loaded by a script tag and not intended
+    // as an AMD module. See http://requirejs.org/docs/errors.html#mismatch for
+    // more details.
     root._ = _;
 
-    // define as an anonymous module so, through path mapping, it can be
-    // referenced as the "underscore" module
+    // Define as an anonymous module so, through path mapping, it can be
+    // referenced as the "underscore" module.
     define(function() {
       return _;
     });
   }
-  // check for `exports` after `define` in case a build optimizer adds an `exports` object
+  // Check for `exports` after `define` in case a build optimizer adds an `exports` object.
   else if (freeExports && freeModule) {
-    // in Node.js or RingoJS
+    // Export for Node.js or RingoJS.
     if (moduleExports) {
       (freeModule.exports = _)._ = _;
     }
-    // in Narwhal or Rhino -require
+    // Export for Rhino with CommonJS support.
     else {
       freeExports._ = _;
     }
   }
   else {
-    // in a browser or Rhino
+    // Export for a browser or Rhino.
     root._ = _;
   }
 }.call(this));