#

API Docs for: 3.10.3
Show: Inherited Protected Private Deprecated

# App.Base Class

Uses

- View
- Router
- PjaxBase

Extends Base
Defined in: `app/js/app-base.js:51`
Module: app-base
Parent Module: app

Available since 3.5.0

Provides a top-level application component which manages navigation and views.

This gives you a foundation and structure on which to build your application; it combines robust URL navigation with powerful routing and flexible view management.

## Constructor

### `App.Base`

(

- `[config]`

)

Defined in `app/js/app-base.js:51`

Available since 3.5.0

#### Parameters:

- `[config]` Object optional

  The following are configuration properties that can be specified in addition to default attribute values and the non-attribute properties provided by `Y.Base`:

  - `[views]` Object optional

    Hash of view-name to metadata used to declaratively describe an application's views and their relationship with the app and other views. The views specified here will override any defaults provided by the `views` object on the `prototype`.

- Index
- Methods
- Properties
- Attributes
- Events

## Item Index

### Methods

- _addAttrs
- _addLazyAttr
- _afterActiveViewChange
- _afterContainerChange
- _afterHistoryChange
- _aggregateAttrs
- _attachView
- _attrCfgHash
- _baseDestroy
- _baseInit
- _cloneDefaultValue
- _decode
- _defAttrChangeFn
- _defDestroyFn
- _defInitFn
- _defNavigateFn
- _defReadyFn
- _dequeue
- _destroyContainer
- _destroyHierarchy
- _detachView
- _dispatch
- _filterAdHocAttrs
- _filterAttrCfgs
- _fireAttrChange
- _getAttr
- _getAttrCfg
- _getAttrCfgs
- _getAttrInitVal
- _getAttrs
- _getClasses
- _getContainer
- _getFullType
- _getHashPath
- _getOrigin
- _getPath
- _getPathRoot
- _getQuery
- _getRegex
- _getRequest
- _getResponse
- _getRoutes
- _getStateVal
- _getType
- _getURL
- _getViewContainer
- _hasSameOrigin
- _initAttrHost
- _initAttribute
- _initAttrs
- _initBase
- _initHierarchy
- _initHierarchyData
- _initHtml5
- _isChildView
- _isLazyAttr
- _isLinkSameOrigin
- _isParentView
- _joinURL
- _monitor
- _navigate
- _normalizePath
- _normAttrVals
- _onLinkClick
- _parseQuery
- _parseType
- _pjaxBindUI
- _preInitEventCfg
- _protectAttrs deprecated
- _publish
- _queue
- _resolvePath
- _resolveURL
- _save
- _set
- _setAttr
- _setAttrs
- _setAttrVal
- _setRoutes
- _setStateVal
- _uiSetActiveView
- _upgradeURL
- addAttr
- addAttrs
- addTarget
- after
- attachEvents
- attrAdded
- before
- bubble
- create
- createView
- destroy
- detach
- detachAll
- detachEvents
- dispatch
- fire
- get
- getAttrs
- getEvent
- getPath
- getTargets
- getViewInfo
- hasRoute
- init
- match
- modifyAttr
- navigate
- on
- once
- onceAfter
- parseType
- publish
- remove
- removeAttr
- removeQuery
- removeRoot
- removeTarget
- render
- replace
- reset
- route
- save
- set
- setAttrs
- showView
- subscribe deprecated
- toString
- unsubscribe deprecated
- unsubscribeAll deprecated
- upgrade

### Properties

- _allowAdHocAttrs
- _dispatched
- _dispatching
- _historyEvents
- _html5
- _NON_ATTRS_CFG static
- _pjaxEvents
- _ready
- _regexPathParam
- _regexURL
- _regexUrlOrigin
- _regexUrlQuery
- _viewInfoMap
- containerTemplate
- events
- name deprecated
- template
- views

### Attributes

- activeView
- container
- destroyed
- html5
- initialized
- linkSelector
- navigateOnHash
- root
- routes
- scrollToTop
- serverRouting
- viewContainer

### Events

- destroy
- init
- navigate
- ready

## Methods

### `_addAttrs`

(

- `cfgs`
- `values`
- `lazy`

)
private

Inherited from AttributeCore: `attribute/js/AttributeCore.js:836`

Implementation behind the public addAttrs method.

This method is invoked directly by get if it encounters a scenario in which an attribute's valueFn attempts to obtain the value an attribute in the same group of attributes, which has not yet been added (on demand initialization).

#### Parameters:

- `cfgs` Object

  An object with attribute name/configuration pairs.

- `values` Object

  An object with attribute name/value pairs, defining the initial values to apply. Values defined in the cfgs argument will be over-written by values in this argument unless defined as read only.

- `lazy` Boolean

  Whether or not to delay the intialization of these attributes until the first call to get/set. Individual attributes can over-ride this behavior by defining a lazyAdd configuration property in their configuration. See addAttr.

### `_addLazyAttr`

(

- `name`
- `[lazyCfg]`

)
private

Inherited from AttributeCore: `attribute/js/AttributeCore.js:382`

Finishes initializing an attribute which has been lazily added.

#### Parameters:

- `name` Object

  The name of the attribute

- `[lazyCfg]` Object optional

  Optional config hash for the attribute. This is added for performance along the critical path, where the calling method has already obtained lazy config from state.

### `_afterActiveViewChange`

(

- `e`

)
protected

Defined in `app/js/app-base.js:801`

Available since 3.5.0

Handles the application's `activeViewChange` event (which is fired when the `activeView` attribute changes) by detaching the old view, attaching the new view.

The `activeView` attribute is read-only, so the public API to change its value is through the `showView()` method.

#### Parameters:

- `e` EventFacade

### `_afterContainerChange`

() protected

Inherited from View: `app/js/view.js:357`

Available since 3.5.0

Handles `containerChange` events. Detaches event handlers from the old container (if any) and attaches them to the new container.

Right now the `container` attr is initOnly so this event should only ever fire the first time the container is created, but in the future (once Y.App can handle it) we may allow runtime container changes.

### `_afterHistoryChange`

(

- `e`

)
protected

Inherited from Router: `app/js/router.js:1269`

Handles `history:change` and `hashchange` events.

#### Parameters:

- `e` EventFacade

### `_aggregateAttrs`

(

- `allAttrs`

)
Object private

Inherited from BaseCore: `base/js/BaseCore.js:575`

A helper method, used by _initHierarchyData to aggregate attribute configuration across the instances class hierarchy.

The method will protect the attribute configuration value to protect the statically defined default value in ATTRS if required (if the value is an object literal, array or the attribute configuration has cloneDefaultValue set to shallow or deep).

#### Parameters:

- `allAttrs` Array

  An array of ATTRS definitions across classes in the hierarchy (subclass first, Base last)

#### Returns:

Object: The aggregate set of ATTRS definitions for the instance

### `_attachView`

(

- `view`
- `prepend=false`

)
protected

Defined in `app/js/app-base.js:434`

Available since 3.5.0

Helper method to attach the view instance to the application by making the app a bubble target of the view, append the view to the `viewContainer`, and assign it to the `instance` property of the associated view info metadata.

#### Parameters:

- `view` View

  View to attach.

- `prepend=false` Boolean

  Whether the view should be prepended instead of appended to the `viewContainer`.

### `_attrCfgHash`

() private

Inherited from BaseCore: `base/js/BaseCore.js:538`

Utility method to define the attribute hash used to filter/whitelist property mixes for this class for iteration performance reasons.

### `_baseDestroy`

() private

Inherited from BaseCore: `base/js/BaseCore.js:309`

Internal destroy implementation for BaseCore

### `_baseInit`

() private

Inherited from BaseCore: `base/js/BaseCore.js:281`

Internal initialization implementation for BaseCore

### `_cloneDefaultValue`

(

- `cfg`

)
private

Inherited from BaseCore: `base/js/BaseCore.js:549`

This method assumes that the value has already been checked to be an object. Since it's on a critical path, we don't want to re-do the check.

#### Parameters:

- `cfg` Object

### `_decode`

(

- `string`

)
String protected

Inherited from Router: `app/js/router.js:564`

Wrapper around `decodeURIComponent` that also converts `+` chars into spaces.

#### Parameters:

- `string` String

  String to decode.

#### Returns:

String: Decoded string.

### `_defAttrChangeFn`

(

- `e`

)
private

Inherited from AttributeObservable: `attribute/js/AttributeObservable.js:186`

Default function for attribute change events.

#### Parameters:

- `e` EventFacade

  The event object for attribute change events.

### `_defDestroyFn`

(

- `e`

)
protected

Inherited from BaseObservable: `base/js/BaseObservable.js:190`

Default destroy event handler

#### Parameters:

- `e` EventFacade

  Event object

### `_defInitFn`

(

- `e`

)
protected

Inherited from BaseObservable: `base/js/BaseObservable.js:178`

Default init event handler

#### Parameters:

- `e` EventFacade

  Event object, with a cfg property which refers to the configuration object passed to the constructor.

### `_defNavigateFn`

(

- `e`

)
protected

Inherited from PjaxBase: `pjax/js/pjax-base.js:300`

Available since 3.5.0

Default handler for the `navigate` event.

Adds a new history entry or replaces the current entry for the specified URL and will scroll the page to the top if configured to do so.

#### Parameters:

- `e` EventFacade

### `_defReadyFn`

(

- `e`

)
protected

Inherited from Router: `app/js/router.js:1300`

Default handler for the `ready` event.

#### Parameters:

- `e` EventFacade

### `_dequeue`

() protected chainable

Inherited from Router: `app/js/router.js:577`

Shifts the topmost `_save()` call off the queue and executes it. Does nothing if the queue is empty.

### `_destroyContainer`

() protected

Inherited from View but overwritten in `app/js/app-base.js:472`

Overrides View's container destruction to deal with the `viewContainer` and checks to make sure not to remove and purge the `<body>`.

### `_destroyHierarchy`

() private

Inherited from BaseCore: `base/js/BaseCore.js:721`

Destroys the class hierarchy for this instance by invoking the destructor method on the prototype of each class in the hierarchy.

### `_detachView`

(

- `view`

)
protected

Defined in `app/js/app-base.js:514`

Available since 3.5.0

Helper method to detach the view instance from the application by removing the application as a bubble target of the view, and either just removing the view if it is intended to be preserved, or destroying the instance completely.

#### Parameters:

- `view` View

  View to detach.

### `_dispatch`

(

- `path`
- `url`
- `src`

)
protected chainable

Inherited from Router: `app/js/router.js:605`

Dispatches to the first route handler that matches the specified path.

If called before the `ready` event has fired, the dispatch will be aborted. This ensures normalized behavior between Chrome (which fires a `popstate` event on every pageview) and other browsers (which do not).

#### Parameters:

- `path` String

  URL path.

- `url` String

  Full URL.

- `src` String

  What initiated the dispatch.

### `_filterAdHocAttrs`

(

- `allAttrs`
- `userVals`

)
Object private

Inherited from BaseCore: `base/js/BaseCore.js:427`

#### Parameters:

- `allAttrs` Object

  The set of all attribute configurations for this instance. Attributes will be removed from this set, if they belong to the filtered class, so that by the time all classes are processed, allCfgs will be empty.

- `userVals` Object

  The config object passed in by the user, from which adhoc attrs are to be filtered.

#### Returns:

Object: The set of adhoc attributes passed in, in the form of an object with attribute name/configuration pairs.

### `_filterAttrCfgs`

(

- `clazz`
- `allCfgs`

)
Object private

Inherited from BaseCore: `base/js/BaseCore.js:356`

A helper method used when processing ATTRS across the class hierarchy during initialization. Returns a disposable object with the attributes defined for the provided class, extracted from the set of all attributes passed in.

#### Parameters:

- `clazz` Function

  The class for which the desired attributes are required.

- `allCfgs` Object

  The set of all attribute configurations for this instance. Attributes will be removed from this set, if they belong to the filtered class, so that by the time all classes are processed, allCfgs will be empty.

#### Returns:

Object: The set of attributes belonging to the class passed in, in the form of an object with attribute name/configuration pairs.

### `_fireAttrChange`

(

- `attrName`
- `subAttrName`
- `currVal`
- `newVal`
- `opts`
- `[cfg]`

)
private

Inherited from AttributeObservable: `attribute/js/AttributeObservable.js:120`

Utility method to help setup the event payload and fire the attribute change event.

#### Parameters:

- `attrName` String

  The name of the attribute

- `subAttrName` String

  The full path of the property being changed, if this is a sub-attribute value being change. Otherwise null.

- `currVal` Any

  The current value of the attribute

- `newVal` Any

  The new value of the attribute

- `opts` Object

  Any additional event data to mix into the attribute change event's event facade.

- `[cfg]` Object optional

  The attribute config stored in State, if already available.

### `_getAttr`

(

- `name`

)
Any protected chainable

Inherited from AttributeCore: `attribute/js/AttributeCore.js:543`

Provides the common implementation for the public get method, allowing Attribute hosts to over-ride either method.

See get for argument details.

#### Parameters:

- `name` String

  The name of the attribute.

#### Returns:

Any: The value of the attribute.

### `_getAttrCfg`

(

- `name`

)
Object protected

Inherited from AttributeExtras: `attribute/js/AttributeExtras.js:114`

Returns an object with the configuration properties (and value) for the given attribute. If attrName is not provided, returns the configuration properties for all attributes.

#### Parameters:

- `name` String

  Optional. The attribute name. If not provided, the method will return the configuration for all attributes.

#### Returns:

Object: The configuration properties for the given attribute, or all attributes.

### `_getAttrCfgs`

() Object protected

Inherited from BaseCore: `base/js/BaseCore.js:339`

Returns an aggregated set of attribute configurations, by traversing the class hierarchy.

#### Returns:

Object: The hash of attribute configurations, aggregated across classes in the hierarchy This value is cached the first time the method, or _getClasses, is invoked. Subsequent invocations return the cached value.

### `_getAttrInitVal`

(

- `attr`
- `cfg`
- `initValues`

)
Any private

Inherited from AttributeCore: `attribute/js/AttributeCore.js:945`

Returns the initial value of the given attribute from either the default configuration provided, or the over-ridden value if it exists in the set of initValues provided and the attribute is not read-only.

#### Parameters:

- `attr` String

  The name of the attribute

- `cfg` Object

  The attribute configuration object

- `initValues` Object

  The object with simple and complex attribute name/value pairs returned from _normAttrVals

#### Returns:

Any: The initial value of the attribute.

### `_getAttrs`

(

- `attrs`

)
Object protected

Inherited from AttributeCore: `attribute/js/AttributeCore.js:774`

Implementation behind the public getAttrs method, to get multiple attribute values.

#### Parameters:

- `attrs` Array | boolean

  Optional. An array of attribute names. If omitted, all attribute values are returned. If set to true, all attributes modified from their initial values are returned.

#### Returns:

Object: An object with attribute name/value pairs.

### `_getClasses`

() Function[] protected

Inherited from BaseCore: `base/js/BaseCore.js:323`

Returns the class hierarchy for this object, with BaseCore being the last class in the array.

#### Returns:

Function[]: An array of classes (constructor functions), making up the class hierarchy for this object. This value is cached the first time the method, or _getAttrCfgs, is invoked. Subsequent invocations return the cached value.

### `_getContainer`

(

- `value`

)
Node protected

Inherited from View: `app/js/view.js:323`

Available since 3.5.0

Getter for the `container` attribute.

#### Parameters:

- `value` Node | Null

  Current attribute value.

#### Returns:

Node: Container node.

### `_getFullType`

(

- `type`

)
String private

Inherited from EventTarget: `event-custom/js/event-target.js:586`

Returns the fully qualified type, given a short type string. That is, returns "foo:bar" when given "bar" if "foo" is the configured prefix.

NOTE: This method, unlike _getType, does no checking of the value passed in, and is designed to be used with the low level _publish() method, for critical path implementations which need to fast-track publish for performance reasons.

#### Parameters:

- `type` String

  The short type to prefix

#### Returns:

String: The prefixed type, if a prefix is set, otherwise the type passed in

### `_getHashPath`

(

- `[hash]`

)
String protected

Inherited from Router: `app/js/router.js:697`

Returns the resolved path from the hash fragment, or an empty string if the hash is not path-like.

#### Parameters:

- `[hash]` String optional

  Hash fragment to resolve into a path. By default this will be the hash from the current URL.

#### Returns:

String: Current hash path, or an empty string if the hash is empty.

### `_getOrigin`

() String protected

Inherited from Router: `app/js/router.js:718`

Gets the location origin (i.e., protocol, host, and port) as a URL.

#### Returns:

String: Location origin (i.e., protocol, host, and port).

#### Example:

    http://example.com

### `_getPath`

() String protected

Inherited from Router: `app/js/router.js:733`

Gets the current route path, relative to the `root` (if any).

#### Returns:

String: Current route path.

### `_getPathRoot`

() String protected

Inherited from Router: `app/js/router.js:747`

Available since 3.5.0

Returns the current path root after popping off the last path segment, making it useful for resolving other URL paths against.

The path root will always begin and end with a '/'.

#### Returns:

String: The URL's path root.

### `_getQuery`

() String protected

Inherited from Router: `app/js/router.js:773`

Gets the current route query string.

#### Returns:

String: Current route query string.

### `_getRegex`

(

- `path`
- `keys`

)
RegExp protected

Inherited from Router: `app/js/router.js:794`

Creates a regular expression from the given route specification. If path is already a regex, it will be returned unmodified.

#### Parameters:

- `path` String | RegExp

  Route path specification.

- `keys` Array

  Array reference to which route parameter names will be added.

#### Returns:

RegExp: Route regex.

### `_getRequest`

(

- `path`
- `url`
- `src`

)
Object protected

Inherited from Router: `app/js/router.js:829`

Gets a request object that can be passed to a route handler.

#### Parameters:

- `path` String

  Current path being dispatched.

- `url` String

  Current full URL being dispatched.

- `src` String

  What initiated the dispatch.

#### Returns:

Object: Request object.

### `_getResponse`

(

- `req`

)
Object protected

Inherited from Router: `app/js/router.js:848`

Gets a response object that can be passed to a route handler.

#### Parameters:

- `req` Object

  Request object.

#### Returns:

Object: Response Object.

### `_getRoutes`

() Object[] protected

Inherited from Router: `app/js/router.js:867`

Getter for the `routes` attribute.

#### Returns:

Object[]: Array of route objects.

### `_getStateVal`

(

- `name`
- `[cfg]`

)
Any private

Inherited from AttributeCore: `attribute/js/AttributeCore.js:600`

Gets the stored value for the attribute, from either the internal state object, or the state proxy if it exits

#### Parameters:

- `name` String

  The name of the attribute

- `[cfg]` Object optional

  Optional config hash for the attribute. This is added for performance along the critical path, where the calling method has already obtained the config from state.

#### Returns:

Any: The stored value of the attribute

### `_getType`

() private

Inherited from EventTarget: `event-custom/js/event-target.js:36`

If the instance has a prefix attribute and the event type is not prefixed, the instance prefix is applied to the supplied type.

### `_getURL`

() String protected

Inherited from Router: `app/js/router.js:878`

Gets the current full URL.

#### Returns:

String: URL.

### `_getViewContainer`

(

- `value`

)
Node protected

Defined in `app/js/app-base.js:555`

Available since 3.5.0

Getter for the `viewContainer` attribute.

#### Parameters:

- `value` Node | Null

  Current attribute value.

#### Returns:

Node: View container node.

### `_hasSameOrigin`

(

- `url`

)
Boolean protected

Inherited from Router: `app/js/router.js:895`

Returns `true` when the specified `url` is from the same origin as the current URL; i.e., the protocol, host, and port of the URLs are the same.

All host or path relative URLs are of the same origin. A scheme-relative URL is first prefixed with the current scheme before being evaluated.

#### Parameters:

- `url` String

  URL to compare origin with the current URL.

#### Returns:

Boolean: Whether the URL has the same origin of the current URL.

### `_initAttrHost`

(

- `attrs`
- `values`
- `lazy`

)
private

Inherited from AttributeCore: `attribute/js/AttributeCore.js:140`

Constructor logic for attributes. Initializes the host state, and sets up the inital attributes passed to the constructor.

#### Parameters:

- `attrs` Object

  The attributes to add during construction (passed through to addAttrs). These can also be defined on the constructor being augmented with Attribute by defining the ATTRS property on the constructor.

- `values` Object

  The initial attribute values to apply (passed through to addAttrs). These are not merged/cloned. The caller is responsible for isolating user provided values if required.

- `lazy` Boolean

  Whether or not to add attributes lazily (passed through to addAttrs).

### `_initAttribute`

() private

Inherited from BaseObservable but overwritten in `base/js/BaseCore.js:254`

Initializes AttributeCore

### `_initAttrs`

(

- `attrs`
- `values`
- `lazy`

)
protected

Inherited from AttributeCore: `attribute/js/AttributeCore.js:1011`

Utility method to set up initial attributes defined during construction, either through the constructor.ATTRS property, or explicitly passed in.

#### Parameters:

- `attrs` Object

  The attributes to add during construction (passed through to addAttrs). These can also be defined on the constructor being augmented with Attribute by defining the ATTRS property on the constructor.

- `values` Object

  The initial attribute values to apply (passed through to addAttrs). These are not merged/cloned. The caller is responsible for isolating user provided values if required.

- `lazy` Boolean

  Whether or not to add attributes lazily (passed through to addAttrs).

### `_initBase`

(

- `config`

)
private

Inherited from BaseCore: `base/js/BaseCore.js:219`

Internal construction logic for BaseCore.

#### Parameters:

- `config` Object

  The constructor configuration object

### `_initHierarchy`

(

- `userVals`

)
private

Inherited from BaseCore: `base/js/BaseCore.js:659`

Initializes the class hierarchy for the instance, which includes initializing attributes for each class defined in the class's static ATTRS property and invoking the initializer method on the prototype of each class in the hierarchy.

#### Parameters:

- `userVals` Object

  Object with configuration property name/value pairs

### `_initHierarchyData`

() private

Inherited from BaseCore: `base/js/BaseCore.js:457`

A helper method used by _getClasses and _getAttrCfgs, which determines both the array of classes and aggregate set of attribute configurations across the class hierarchy for the instance.

### `_initHtml5`

() Boolean protected

Defined in `app/js/app-base.js:580`

Available since 3.5.0

Provides the default value for the `html5` attribute.

The value returned is dependent on the value of the `serverRouting` attribute. When `serverRouting` is explicit set to `false` (not just falsy), the default value for `html5` will be set to `false` for all browsers.

When `serverRouting` is `true` or `undefined` the returned value will be dependent on the browser's capability of using HTML5 history.

#### Returns:

Boolean: Whether or not HTML5 history should be used.

### `_isChildView`

(

- `view`
- `parent`

)
Boolean protected

Defined in `app/js/app-base.js:606`

Available since 3.5.0

Determines if the specified `view` is configured as a child of the specified `parent` view. This requires both views to be either named-views, or view instances created using configuration data that exists in the `views` object, e.g. created by the `createView()` or `showView()` method.

#### Parameters:

- `view` View | String

  The name of a view defined in the `views` object, or a view instance.

- `parent` View | String

  The name of a view defined in the `views` object, or a view instance.

#### Returns:

Boolean: Whether the view is configured as a child of the parent.

### `_isLazyAttr`

(

- `name`

)
Boolean private

Inherited from AttributeCore: `attribute/js/AttributeCore.js:369`

Checks whether or not the attribute is one which has been added lazily and still requires initialization.

#### Parameters:

- `name` String

  The name of the attribute

#### Returns:

Boolean: true if it's a lazily added attribute, false otherwise.

### `_isLinkSameOrigin`

(

- `link`

)
Boolean protected

Inherited from PjaxBase: `pjax/js/pjax-base.js:161`

Available since 3.6.0

Utility method to test whether a specified link/anchor node's `href` is of the same origin as the page's current location.

This normalize browser inconsistencies with how the `port` is reported for anchor elements (IE reports a value for the default port, e.g. "80").

#### Parameters:

- `link` Node

  The anchor element to test whether its `href` is of the same origin as the page's current location.

#### Returns:

Boolean: Whether or not the link's `href` is of the same origin as the page's current location.

### `_isParentView`

(

- `view`
- `parent`

)
Boolean protected

Defined in `app/js/app-base.js:632`

Available since 3.5.0

Determines if the specified `view` is configured as the parent of the specified `child` view. This requires both views to be either named-views, or view instances created using configuration data that exists in the `views` object, e.g. created by the `createView()` or `showView()` method.

#### Parameters:

- `view` View | String

  The name of a view defined in the `views` object, or a view instance.

- `parent` View | String

  The name of a view defined in the `views` object, or a view instance.

#### Returns:

Boolean: Whether the view is configured as the parent of the child.

### `_joinURL`

(

- `url`

)
String protected

Inherited from Router: `app/js/router.js:918`

Joins the `root` URL to the specified url, normalizing leading/trailing `/` characters.

#### Parameters:

- `url` String

  URL to append to the `root` URL.

#### Returns:

String: Joined URL.

#### Example:

    router.set('root', '/foo');
    router._joinURL('bar');  // => '/foo/bar'
    router._joinURL('/bar'); // => '/foo/bar'

    router.set('root', '/foo/');
    router._joinURL('bar');  // => '/foo/bar'
    router._joinURL('/bar'); // => '/foo/bar'

### `_monitor`

(

- `what`
- `eventType`
- `o`

)
private

Inherited from EventTarget: `event-custom/js/event-target.js:658`

This is the entry point for the event monitoring system. You can monitor 'attach', 'detach', 'fire', and 'publish'. When configured, these events generate an event. click -> clickattach, clickdetach, click_publish -- these can be subscribed to like other events to monitor the event system. Inividual published events can have monitoring turned on or off (publish can't be turned off before it it published) by setting the events 'monitor' config.

#### Parameters:

- `what` String

  'attach', 'detach', 'fire', or 'publish'

- `eventType` String | CustomEvent

  The prefixed name of the event being monitored, or the CustomEvent object.

- `o` Object

  Information about the event interaction, such as fire() args, subscription category, publish config

### `_navigate`

(

- `url`
- `[options]`

)
protected

Inherited from PjaxBase but overwritten in `app/js/app-base.js:658`

Underlying implementation for `navigate()`.

#### Parameters:

- `url` String

  The fully-resolved URL that the app should dispatch to its route handlers to fulfill the enhanced navigation "request", or use to update `window.location` in non-HTML5 history capable browsers when `serverRouting` is `true`.

- `[options]` Object optional

  Additional options to configure the navigation. These are mixed into the `navigate` event facade.

  - `[replace]` Boolean optional

    Whether or not the current history entry will be replaced, or a new entry will be created. Will default to `true` if the specified `url` is the same as the current URL.

  - `[force]` Boolean optional

    Whether the enhanced navigation should occur even in browsers without HTML5 history. Will default to `true` when `serverRouting` is falsy.

### `_normalizePath`

(

- `path`

)
String protected

Inherited from Router: `app/js/router.js:951`

Available since 3.5.0

Returns a normalized path, ridding it of any '..' segments and properly handling leading and trailing slashes.

#### Parameters:

- `path` String

  URL path to normalize.

#### Returns:

String: Normalized path.

### `_normAttrVals`

(

- `valueHash`

)
Object private

Inherited from AttributeCore: `attribute/js/AttributeCore.js:897`

Utility method to normalize attribute values. The base implementation simply merges the hash to protect the original.

#### Parameters:

- `valueHash` Object

  An object with attribute name/value pairs

#### Returns:

Object: An object literal with 2 properties - "simple" and "complex", containing simple and complex attribute values respectively keyed by the top level attribute name, or null, if valueHash is falsey.

### `_onLinkClick`

(

- `e`

)
protected

Inherited from PjaxBase: `pjax/js/pjax-base.js:325`

Available since 3.5.0

Handler for delegated link-click events which match the `linkSelector`.

This will attempt to enhance the navigation to the link element's `href` by passing the URL to the `_navigate()` method. When the navigation is being enhanced, the default action is prevented.

If the user clicks a link with the middle/right mouse buttons, or is holding down the Ctrl or Command keys, this method's behavior is not applied and allows the native behavior to occur. Similarly, if the router is not capable or handling the URL because no route-handlers match, the link click will behave natively.

#### Parameters:

- `e` EventFacade

### `_parseQuery`

(

- `query`

)
Object protected

Inherited from Router: `app/js/router.js:993`

Parses a URL query string into a key/value hash. If `Y.QueryString.parse` is available, this method will be an alias to that.

#### Parameters:

- `query` String

  Query string to parse.

#### Returns:

Object: Hash of key/value pairs for query parameters.

### `_parseType`

() private

Inherited from EventTarget: `event-custom/js/event-target.js:52`

Returns an array with the detach key (if provided), and the prefixed event name from _getType Y.on('detachcategory| menu:click', fn)

### `_pjaxBindUI`

() protected

Inherited from PjaxBase: `pjax/js/pjax-base.js:279`

Available since 3.5.0

Binds the delegation of link-click events that match the `linkSelector` to the `_onLinkClick()` handler.

By default this method will only be called if the browser is capable of using HTML5 history.

### `_preInitEventCfg`

(

- `config`

)
private

Inherited from BaseObservable: `base/js/BaseObservable.js:98`

Handles the special on, after and target properties which allow the user to easily configure on and after listeners as well as bubble targets during construction, prior to init.

#### Parameters:

- `config` Object

  The user configuration object

### `_protectAttrs`

(

- `attrs`

)
Object deprecated protected

Inherited from AttributeCore: `attribute/js/AttributeCore.js:883`

Deprecated: Use `AttributeCore.protectAttrs()` or `Attribute.protectAttrs()` which are the same static utility method.

Utility method to protect an attribute configuration hash, by merging the entire object and the individual attr config objects.

#### Parameters:

- `attrs` Object

  A hash of attribute to configuration object pairs.

#### Returns:

Object: A protected version of the attrs argument.

### `_publish`

(

- `fullType`
- `etOpts`
- `ceOpts`

)
CustomEvent private

Inherited from EventTarget: `event-custom/js/event-target.js:610`

The low level event publish implementation. It expects all the massaging to have been done outside of this method. e.g. the `type` to `fullType` conversion. It's designed to be a fast path publish, which can be used by critical code paths to improve performance.

#### Parameters:

- `fullType` String

  The prefixed type of the event to publish.

- `etOpts` Object

  The EventTarget specific configuration to mix into the published event.

- `ceOpts` Object

  The publish specific configuration to mix into the published event.

#### Returns:

CustomEvent: The published event. If called without `etOpts` or `ceOpts`, this will be the default `CustomEvent` instance, and can be configured independently.

### `_queue`

() protected chainable

Inherited from Router: `app/js/router.js:1021`

Queues up a `_save()` call to run after all previously-queued calls have finished.

This is necessary because if we make multiple `_save()` calls before the first call gets dispatched, then both calls will dispatch to the last call's URL.

All arguments passed to `_queue()` will be passed on to `_save()` when the queued function is executed.

### `_resolvePath`

(

- `path`

)
String protected

Inherited from Router: `app/js/router.js:1066`

Available since 3.5.0

Returns the normalized result of resolving the `path` against the current path. Falsy values for `path` will return just the current path.

#### Parameters:

- `path` String

  URL path to resolve.

#### Returns:

String: Resolved path.

### `_resolveURL`

(

- `url`

)
String protected

Inherited from Router: `app/js/router.js:1088`

Available since 3.5.0

Resolves the specified URL against the current URL.

This method resolves URLs like a browser does and will always return an absolute URL. When the specified URL is already absolute, it is assumed to be fully resolved and is simply returned as is. Scheme-relative URLs are prefixed with the current protocol. Relative URLs are giving the current URL's origin and are resolved and normalized against the current path root.

#### Parameters:

- `url` String

  URL to resolve.

#### Returns:

String: Resolved URL.

### `_save`

(

- `[url]`
- `[replace=false]`

)
protected chainable

Inherited from Router but overwritten in `app/js/app-base.js:688`

Will either save a history entry using `pushState()` or the location hash, or gracefully-degrade to sending a request to the server causing a full-page reload.

Overrides Router's `_save()` method to preform graceful-degradation when the app's `serverRouting` is `true` and `html5` is `false` by updating the full URL via standard assignment to `window.location` or by calling `window.location.replace()`; both of which will cause a request to the server resulting in a full-page reload.

Otherwise this will just delegate off to Router's `_save()` method allowing the client-side enhanced routing to occur.

#### Parameters:

- `[url]` String optional

  URL for the history entry.

- `[replace=false]` Boolean optional

  If `true`, the current history entry will be replaced instead of a new one being added.

### `_set`

(

- `name`
- `val`
- `[opts]`

)
Object protected chainable

Inherited from AttributeObservable but overwritten in `attribute/js/AttributeCore.js:427`

Allows setting of readOnly/writeOnce attributes. See set for argument details.

#### Parameters:

- `name` String

  The name of the attribute.

- `val` Any

  The value to set the attribute to.

- `[opts]` Object optional

  Optional data providing the circumstances for the change.

#### Returns:

Object: A reference to the host object.

### `_setAttr`

(

- `name`
- `value`
- `[opts]`
- `force`

)
Object protected chainable

Inherited from AttributeCore: `attribute/js/AttributeCore.js:443`

Provides the common implementation for the public set and protected _set methods.

See set for argument details.

#### Parameters:

- `name` String

  The name of the attribute.

- `value` Any

  The value to set the attribute to.

- `[opts]` Object optional

  Optional data providing the circumstances for the change.

- `force` Boolean

  If true, allows the caller to set values for readOnly or writeOnce attributes which have already been set.

#### Returns:

Object: A reference to the host object.

### `_setAttrs`

(

- `attrs`
- `[opts]`

)
Object protected chainable

Inherited from AttributeObservable but overwritten in `attribute/js/AttributeCore.js:742`

Implementation behind the public setAttrs method, to set multiple attribute values.

#### Parameters:

- `attrs` Object

  An object with attributes name/value pairs.

- `[opts]` Object optional

  Optional data providing the circumstances for the change

#### Returns:

Object: A reference to the host object.

### `_setAttrVal`

(

- `attrName`
- `subAttrName`
- `prevVal`
- `newVal`
- `[opts]`
- `[attrCfg]`

)
Booolean private

Inherited from AttributeCore: `attribute/js/AttributeCore.js:640`

Updates the stored value of the attribute in the privately held State object, if validation and setter passes.

#### Parameters:

- `attrName` String

  The attribute name.

- `subAttrName` String

  The sub-attribute name, if setting a sub-attribute property ("x.y.z").

- `prevVal` Any

  The currently stored value of the attribute.

- `newVal` Any

  The value which is going to be stored.

- `[opts]` Object optional

  Optional data providing the circumstances for the change.

- `[attrCfg]` Object optional

  Optional config hash for the attribute. This is added for performance along the critical path, where the calling method has already obtained the config from state.

#### Returns:

Booolean: true if the new attribute value was stored, false if not.

### `_setRoutes`

(

- `routes`

)
Object[] protected

Inherited from Router: `app/js/router.js:1203`

Setter for the `routes` attribute.

#### Parameters:

- `routes` Object[]

  Array of route objects.

#### Returns:

Object[]: Array of route objects.

### `_setStateVal`

(

- `name`
- `value`

)
private

Inherited from AttributeCore: `attribute/js/AttributeCore.js:622`

Sets the stored value for the attribute, in either the internal state object, or the state proxy if it exits

#### Parameters:

- `name` String

  The name of the attribute

- `value` Any

  The value of the attribute

### `_uiSetActiveView`

(

- `newView`
- `[oldView]`
- `[options]`

)
protected

Defined in `app/js/app-base.js:741`

Available since 3.5.0

Performs the actual change of this app's `activeView` by attaching the `newView` to this app, and detaching the `oldView` from this app using any specified `options`.

The `newView` is attached to the app by rendering it to the `viewContainer`, and making this app a bubble target of its events.

The `oldView` is detached from the app by removing it from the `viewContainer`, and removing this app as a bubble target for its events. The `oldView` will either be preserved or properly destroyed.

Note: The `activeView` attribute is read-only and can be changed by calling the `showView()` method.

#### Parameters:

- `newView` View

  The View which is now this app's `activeView`.

- `[oldView]` View optional

  The View which was this app's `activeView`.

- `[options]` Object optional

  Optional object containing any of the following properties:

  - `[callback]` Function optional

    Optional callback function to call after new `activeView` is ready to use, the function will be passed:

    - `view` View
      A reference to the new `activeView`.
  - `[prepend=false]` Boolean optional

    Whether the `view` should be prepended instead of appended to the `viewContainer`.

  - `[render]` Boolean optional

    Whether the `view` should be rendered. Note: If no value is specified, a view instance will only be rendered if it's newly created by this method.

  - `[update=false]` Boolean optional

    Whether an existing view should have its attributes updated by passing the `config` object to its `setAttrs()` method. Note: This option does not have an effect if the `view` instance is created as a result of calling this method.

### `_upgradeURL`

(

- `url`

)
String protected

Inherited from Router: `app/js/router.js:1224`

Available since 3.5.0

Upgrades a hash-based URL to a full-path URL, if necessary.

The specified `url` will be upgraded if its of the same origin as the current URL and has a path-like hash. URLs that don't need upgrading will be returned as-is.

#### Parameters:

- `url` String

  The URL to upgrade from hash-based to full-path.

#### Returns:

String: The upgraded URL, or the specified URL untouched.

#### Example:

    app._upgradeURL('http://example.com/#/foo/'); // => 'http://example.com/foo/';

### `addAttr`

(

- `name`
- `config`
- `lazy`

)
Object chainable

Inherited from AttributeCore: `attribute/js/AttributeCore.js:157`

Adds an attribute with the provided configuration to the host object.

The config argument object supports the following properties:

value <Any>
  The initial value to set on the attribute
valueFn <Function | String>

  A function, which will return the initial value to set on the attribute. This is useful for cases where the attribute configuration is defined statically, but needs to reference the host instance ("this") to obtain an initial value. If both the value and valueFn properties are defined, the value returned by the valueFn has precedence over the value property, unless it returns undefined, in which case the value property is used.

  valueFn can also be set to a string, representing the name of the instance method to be used to retrieve the value.

readOnly <boolean>
  Whether or not the attribute is read only. Attributes having readOnly set to true cannot be modified by invoking the set method.
writeOnce <boolean> or <string>
  Whether or not the attribute is "write once". Attributes having writeOnce set to true, can only have their values set once, be it through the default configuration, constructor configuration arguments, or by invoking set.

  The writeOnce attribute can also be set to the string "initOnly", in which case the attribute can only be set during initialization (when used with Base, this means it can only be set during construction)

setter <Function | String>

  The setter function used to massage or normalize the value passed to the set method for the attribute. The value returned by the setter will be the final stored value. Returning Attribute.INVALID_VALUE, from the setter will prevent the value from being stored.

  setter can also be set to a string, representing the name of the instance method to be used as the setter function.

getter <Function | String>

  The getter function used to massage or normalize the value returned by the get method for the attribute. The value returned by the getter function is the value which will be returned to the user when they invoke get.

  getter can also be set to a string, representing the name of the instance method to be used as the getter function.

validator <Function | String>

  The validator function invoked prior to setting the stored value. Returning false from the validator function will prevent the value from being stored.

  validator can also be set to a string, representing the name of the instance method to be used as the validator function.

lazyAdd <boolean>
  Whether or not to delay initialization of the attribute until the first call to get/set it. This flag can be used to over-ride lazy initialization on a per attribute basis, when adding multiple attributes through the addAttrs method.

The setter, getter and validator are invoked with the value and name passed in as the first and second arguments, and with the context ("this") set to the host object.

Configuration properties outside of the list mentioned above are considered private properties used internally by attribute, and are not intended for public use.

#### Parameters:

- `name` String

  The name of the attribute.

- `config` Object

  An object with attribute configuration property/value pairs, specifying the configuration for the attribute.

  NOTE: The configuration object is modified when adding an attribute, so if you need to protect the original values, you will need to merge the object.

- `lazy` Boolean

  (optional) Whether or not to add this attribute lazily (on the first call to get/set).

#### Returns:

Object: A reference to the host object.

### `addAttrs`

(

- `cfgs`
- `values`
- `lazy`

)
Object chainable

Inherited from AttributeCore: `attribute/js/AttributeCore.js:805`

Configures a group of attributes, and sets initial values.

NOTE: This method does not isolate the configuration object by merging/cloning. The caller is responsible for merging/cloning the configuration object if required.

#### Parameters:

- `cfgs` Object

  An object with attribute name/configuration pairs.

- `values` Object

  An object with attribute name/value pairs, defining the initial values to apply. Values defined in the cfgs argument will be over-written by values in this argument unless defined as read only.

- `lazy` Boolean

  Whether or not to delay the intialization of these attributes until the first call to get/set. Individual attributes can over-ride this behavior by defining a lazyAdd configuration property in their configuration. See addAttr.

#### Returns:

Object: A reference to the host object.

### `addTarget`

(

- `o`

)

Inherited from EventTarget: `event-custom/js/event-facade.js:455`

Registers another EventTarget as a bubble target. Bubble order is determined by the order registered. Multiple targets can be specified.

Events can only bubble if emitFacade is true.

Included in the event-custom-complex submodule.

#### Parameters:

- `o` EventTarget

  the target to add

### `after`

(

- `type`
- `fn`
- `[context]`
- `[arg*]`

)
EventHandle

Inherited from EventTarget: `event-custom/js/event-target.js:833`

Subscribe to a custom event hosted by this object. The supplied callback will execute after any listeners add via the subscribe method, and after the default function, if configured for the event, has executed.

#### Parameters:

- `type` String

  The name of the event

- `fn` Function

  The callback to execute in response to the event

- `[context]` Object optional

  Override `this` object in callback

- `[arg*]` Any optional

  0..n additional arguments to supply to the subscriber

#### Returns:

EventHandle: A subscription handle capable of detaching the subscription

### `attachEvents`

(

- `[events]`

)
chainable

Inherited from View: `app/js/view.js:181`

Attaches delegated event handlers to this view's container element. This method is called internally to subscribe to events configured in the `events` attribute when the view is initialized.

You may override this method to customize the event attaching logic.

#### Parameters:

- `[events]` Object optional

  Hash of events to attach. See the docs for the `events` attribute for details on the format. If not specified, this view's `events` property will be used.

### `attrAdded`

(

- `name`

)
Boolean

Inherited from AttributeCore: `attribute/js/AttributeCore.js:341`

Checks if the given attribute has been added to the host

#### Parameters:

- `name` String

  The name of the attribute to check.

#### Returns:

Boolean: true if an attribute with the given name has been added, false if it hasn't. This method will return true for lazily added attributes.

### `before`

()

Inherited from EventTarget: `event-custom/js/event-target.js:870`

Executes the callback before a DOM event, custom event or method. If the first argument is a function, it is assumed the target is a method. For DOM and custom events, this is an alias for Y.on.

For DOM and custom events: type, callback, context, 0-n arguments

For methods: callback, object (method host), methodName, context, 0-n arguments

#### Returns:

detach handle

### `bubble`

(

- `evt`

)
Boolean

Inherited from EventTarget: `event-custom/js/event-facade.js:507`

Propagate an event. Requires the event-custom-complex module.

#### Parameters:

- `evt` CustomEvent

  the custom event to propagate

#### Returns:

Boolean: the aggregated return value from Event.Custom.fire

### `create`

(

- `[container]`

)
Node

Inherited from View: `app/js/view.js:233`

Creates and returns a container node for this view.

By default, the container is created from the HTML template specified in the `containerTemplate` property, and is not added to the DOM automatically.

You may override this method to customize how the container node is created (such as by rendering it from a custom template format). Your method must return a `Y.Node` instance.

#### Parameters:

- `[container]` HTMLElement | Node | String optional

  Selector string, `Y.Node` instance, or DOM element to use at the container node.

#### Returns:

Node: Node instance of the created container node.

### `createView`

(

- `name`
- `[config]`

)
View

Defined in `app/js/app-base.js:185`

Available since 3.5.0

Creates and returns a new view instance using the provided `name` to look up the view info metadata defined in the `views` object. The passed-in `config` object is passed to the view constructor function.

This function also maps a view instance back to its view info metadata.

#### Parameters:

- `name` String

  The name of a view defined on the `views` object.

- `[config]` Object optional

  The configuration object passed to the view constructor function when creating the new view instance.

#### Returns:

View: The new view instance.

### `destroy`

(

- `[options]`

)
chainable

Inherited from BaseObservable but overwritten in `app/js/view.js:146`

Destroys this View, detaching any DOM events and optionally also destroying its container node.

By default, the container node will not be destroyed. Pass an options object with a truthy `remove` property to destroy the container as well.

#### Parameters:

- `[options]` Object optional

  Options.

  - `[remove=false]` Boolean optional

    If `true`, this View's container will be removed from the DOM and destroyed as well.

### `detach`

(

- `type`
- `fn`
- `context`

)
EventTarget

Inherited from EventTarget: `event-custom/js/event-target.js:346`

Detach one or more listeners the from the specified event

#### Parameters:

- `type` String | Object

  Either the handle to the subscriber or the type of event. If the type is not specified, it will attempt to remove the listener from all hosted events.

- `fn` Function

  The subscribed function to unsubscribe, if not supplied, all subscribers will be removed.

- `context` Object

  The custom object passed to subscribe. This is optional, but if supplied will be used to disambiguate multiple listeners that are the same (e.g., you subscribe many object using a function that lives on the prototype)

#### Returns:

EventTarget: the host

### `detachAll`

(

- `type`

)

Inherited from EventTarget: `event-custom/js/event-target.js:469`

Removes all listeners from the specified event. If the event type is not specified, all listeners from all hosted custom events will be removed.

#### Parameters:

- `type` String

  The type, or name of the event

### `detachEvents`

() chainable

Inherited from View: `app/js/view.js:253`

Detaches DOM events that have previously been attached to the container by `attachEvents()`.

### `dispatch`

() chainable

Inherited from Router: `app/js/router.js:206`

Dispatches to the first route handler that matches the current URL, if any.

If `dispatch()` is called before the `ready` event has fired, it will automatically wait for the `ready` event before dispatching. Otherwise it will dispatch immediately.

### `fire`

(

- `type`
- `arguments`

)
EventTarget

Inherited from EventTarget: `event-custom/js/event-target.js:695`

Fire a custom event by name. The callback functions will be executed from the context specified when the event was created, and with the following parameters.

If the custom event object hasn't been created, then the event hasn't been published and it has no subscribers. For performance sake, we immediate exit in this case. This means the event won't bubble, so if the intention is that a bubble target be notified, the event must be published on this object first.

The first argument is the event type, and any additional arguments are passed to the listeners as parameters. If the first of these is an object literal, and the event is configured to emit an event facade, that object is mixed into the event facade and the facade is provided in place of the original object.

#### Parameters:

- `type` String | Object

  The type of the event, or an object that contains a 'type' property.

- `arguments` Object*

  an arbitrary set of parameters to pass to the handler. If the first of these is an object literal and the event is configured to emit an event facade, the event facade will replace that parameter after the properties the object literal contains are copied to the event facade.

#### Returns:

EventTarget: the event host

### `get`

(

- `name`

)
Any

Inherited from AttributeCore: `attribute/js/AttributeCore.js:353`

Returns the current value of the attribute. If the attribute has been configured with a 'getter' function, this method will delegate to the 'getter' to obtain the value of the attribute.

#### Parameters:

- `name` String

  The name of the attribute. If the value of the attribute is an Object, dot notation can be used to obtain the value of a property of the object (e.g. `get("x.y.z")`)

#### Returns:

Any: The value of the attribute

### `getAttrs`

(

- `attrs`

)
Object

Inherited from AttributeCore: `attribute/js/AttributeCore.js:762`

Gets multiple attribute values.

#### Parameters:

- `attrs` Array | boolean

  Optional. An array of attribute names. If omitted, all attribute values are returned. If set to true, all attributes modified from their initial values are returned.

#### Returns:

Object: An object with attribute name/value pairs.

### `getEvent`

(

- `type`
- `prefixed`

)
CustomEvent

Inherited from EventTarget: `event-custom/js/event-target.js:814`

Returns the custom event of the provided type has been created, a falsy value otherwise

#### Parameters:

- `type` String

  the type, or name of the event

- `prefixed` String

  if true, the type is prefixed already

#### Returns:

CustomEvent: the custom event or null

### `getPath`

() String

Inherited from Router: `app/js/router.js:228`

Gets the current route path, relative to the `root` (if any).

#### Returns:

String: Current route path.

### `getTargets`

()

Inherited from EventTarget: `event-custom/js/event-facade.js:479`

Returns an array of bubble targets for this object.

#### Returns:

EventTarget[]

### `getViewInfo`

(

- `view`

)
Object

Defined in `app/js/app-base.js:215`

Available since 3.5.0

Returns the metadata associated with a view instance or view name defined on the `views` object.

#### Parameters:

- `view` View | String

  View instance, or name of a view defined on the `views` object.

#### Returns:

Object: The metadata for the view, or `undefined` if the view is not registered.

### `hasRoute`

(

- `url`

)
Boolean

Inherited from Router: `app/js/router.js:238`

Returns `true` if this router has at least one route that matches the specified URL, `false` otherwise.

This method enforces the same-origin security constraint on the specified `url`; any URL which is not from the same origin as the current URL will always return `false`.

#### Parameters:

- `url` String

  URL to match.

#### Returns:

Boolean: `true` if there's at least one matching route, `false` otherwise.

### `init`

(

- `cfg`

)
BaseCore chainable

Inherited from BaseObservable but overwritten in `base/js/BaseCore.js:264`

Init lifecycle method, invoked during construction. Sets up attributes and invokes initializers for the class hierarchy.

#### Parameters:

- `cfg` Object

  Object with configuration property name/value pairs

#### Returns:

BaseCore: A reference to this object

### `match`

(

- `path`

)
Object[]

Inherited from Router: `app/js/router.js:267`

Returns an array of route objects that match the specified URL path.

This method is called internally to determine which routes match the current path whenever the URL changes. You may override it if you want to customize the route matching logic, although this usually shouldn't be necessary.

Each returned route object has the following properties:

- `callback`: A function or a string representing the name of a function this router that should be executed when the route is triggered.

- `keys`: An array of strings representing the named parameters defined in the route's path specification, if any.

- `path`: The route's path specification, which may be either a string or a regex.

- `regex`: A regular expression version of the route's path specification. This regex is used to determine whether the route matches a given path.

#### Parameters:

- `path` String

  URL path to match.

#### Returns:

Object[]: Array of route objects that match the specified path.

#### Example:

    router.route('/foo', function () {});
    router.match('/foo');
    // => [{callback: ..., keys: [], path: '/foo', regex: ...}]

### `modifyAttr`

(

- `name`
- `config`

)

Inherited from AttributeExtras: `attribute/js/AttributeExtras.js:40`

Updates the configuration of an attribute which has already been added.

The properties which can be modified through this interface are limited to the following subset of attributes, which can be safely modified after a value has already been set on the attribute: readOnly, writeOnce, broadcast and getter.

#### Parameters:

- `name` String

  The name of the attribute whose configuration is to be updated.

- `config` Object

  An object with configuration property/value pairs, specifying the configuration properties to modify.

### `navigate`

(

- `url`
- `[options]`

)

Inherited from PjaxBase but overwritten in `app/js/app-base.js:234`

Navigates to the specified URL if there is a route handler that matches. In browsers capable of using HTML5 history or when `serverRouting` is falsy, the navigation will be enhanced by firing the `navigate` event and having the app handle the "request". When `serverRouting` is `true`, non-HTML5 browsers will navigate to the new URL via a full page reload.

When there is a route handler for the specified URL and it is being navigated to, this method will return `true`, otherwise it will return `false`.

Note: The specified URL must be of the same origin as the current URL, otherwise an error will be logged and navigation will not occur. This is intended as both a security constraint and a purposely imposed limitation as it does not make sense to tell the app to navigate to a URL on a different scheme, host, or port.

#### Parameters:

- `url` String

  The URL to navigate to. This must be of the same origin as the current URL.

- `[options]` Object optional

  Additional options to configure the navigation. These are mixed into the `navigate` event facade.

  - `[replace]` Boolean optional

    Whether or not the current history entry will be replaced, or a new entry will be created. Will default to `true` if the specified `url` is the same as the current URL.

  - `[force]` Boolean optional

    Whether the enhanced navigation should occur even in browsers without HTML5 history. Will default to `true` when `serverRouting` is falsy.

### `on`

(

- `type`
- `fn`
- `[context]`
- `[arg*]`

)
EventHandle

Inherited from EventTarget: `event-custom/js/event-target.js:188`

Subscribe a callback function to a custom event fired by this object or from an object that bubbles its events to this object.

Callback functions for events published with `emitFacade = true` will receive an `EventFacade` as the first argument (typically named "e"). These callbacks can then call `e.preventDefault()` to disable the behavior published to that event's `defaultFn`. See the `EventFacade` API for all available properties and methods. Subscribers to non-`emitFacade` events will receive the arguments passed to `fire()` after the event name.

To subscribe to multiple events at once, pass an object as the first argument, where the key:value pairs correspond to the eventName:callback, or pass an array of event names as the first argument to subscribe to all listed events with the same callback.

Returning `false` from a callback is supported as an alternative to calling `e.preventDefault(); e.stopPropagation();`. However, it is recommended to use the event methods whenever possible.

#### Parameters:

- `type` String

  The name of the event

- `fn` Function

  The callback to execute in response to the event

- `[context]` Object optional

  Override `this` object in callback

- `[arg*]` Any optional

  0..n additional arguments to supply to the subscriber

#### Returns:

EventHandle: A subscription handle capable of detaching that subscription

### `once`

(

- `type`
- `fn`
- `[context]`
- `[arg*]`

)
EventHandle

Inherited from EventTarget: `event-custom/js/event-target.js:124`

Listen to a custom event hosted by this object one time. This is the equivalent to `on` except the listener is immediatelly detached when it is executed.

#### Parameters:

- `type` String

  The name of the event

- `fn` Function

  The callback to execute in response to the event

- `[context]` Object optional

  Override `this` object in callback

- `[arg*]` Any optional

  0..n additional arguments to supply to the subscriber

#### Returns:

EventHandle: A subscription handle capable of detaching the subscription

### `onceAfter`

(

- `type`
- `fn`
- `[context]`
- `[arg*]`

)
EventHandle

Inherited from EventTarget: `event-custom/js/event-target.js:146`

Listen to a custom event hosted by this object one time. This is the equivalent to `after` except the listener is immediatelly detached when it is executed.

#### Parameters:

- `type` String

  The name of the event

- `fn` Function

  The callback to execute in response to the event

- `[context]` Object optional

  Override `this` object in callback

- `[arg*]` Any optional

  0..n additional arguments to supply to the subscriber

#### Returns:

EventHandle: A subscription handle capable of detaching that subscription

### `parseType`

(

- `type`
- `[pre=this._yuievt.config.prefix]`

)
Array

Inherited from EventTarget: `event-custom/js/event-target.js:168`

Available since 3.3.0

Takes the type parameter passed to 'on' and parses out the various pieces that could be included in the type. If the event type is passed without a prefix, it will be expanded to include the prefix one is supplied or the event target is configured with a default prefix.

#### Parameters:

- `type` String

  the type

- `[pre=this._yuievt.config.prefix]` String optional

  the prefix

#### Returns:

Array: an array containing: * the detach category, if supplied, * the prefixed event type, * whether or not this is an after listener, * the supplied event type

### `publish`

(

- `type`
- `opts`

)
CustomEvent

Inherited from EventTarget: `event-custom/js/event-target.js:493`

Creates a new custom event of the specified type. If a custom event by that name already exists, it will not be re-created. In either case the custom event is returned.

#### Parameters:

- `type` String

  the type, or name of the event

- `opts` Object

  optional config params. Valid properties are:

  - 'broadcast': whether or not the YUI instance and YUI global are notified when the event is fired (false)
  - 'bubbles': whether or not this event bubbles (true) Events can only bubble if emitFacade is true.
  - 'context': the default execution context for the listeners (this)
  - 'defaultFn': the default function to execute when this event fires if preventDefault was not called
  - 'emitFacade': whether or not this event emits a facade (false)
  - 'prefix': the prefix for this targets events, e.g., 'menu' in 'menu:click'
  - 'fireOnce': if an event is configured to fire once, new subscribers after the fire will be notified immediately.
  - 'async': fireOnce event listeners will fire synchronously if the event has already fired unless async is true.
  - 'preventable': whether or not preventDefault() has an effect (true)
  - 'preventedFn': a function that is executed when preventDefault is called
  - 'queuable': whether or not this event can be queued during bubbling (false)
  - 'silent': if silent is true, debug messages are not provided for this event.
  - 'stoppedFn': a function that is executed when stopPropagation is called

  - 'monitored': specifies whether or not this event should send notifications about when the event has been attached, detached, or published.
  - 'type': the event type (valid option if not provided as the first parameter to publish)

#### Returns:

CustomEvent: the custom event

### `remove`

() chainable

Inherited from View: `app/js/view.js:272`

Removes this view's container element from the DOM (if it's in the DOM), but doesn't destroy it or any event listeners attached to it.

### `removeAttr`

(

- `name`

)

Inherited from AttributeExtras: `attribute/js/AttributeExtras.js:79`

Removes an attribute from the host object

#### Parameters:

- `name` String

  The name of the attribute to be removed.

### `removeQuery`

(

- `url`

)
String

Inherited from Router: `app/js/router.js:325`

Removes a query string from the end of the url (if one exists) and returns the result.

#### Parameters:

- `url` String

  URL.

#### Returns:

String: Queryless path.

### `removeRoot`

(

- `url`

)
String

Inherited from Router: `app/js/router.js:303`

Removes the `root` URL from the front of url (if it's there) and returns the result. The returned path will always have a leading `/`.

#### Parameters:

- `url` String

  URL.

#### Returns:

String: Rootless path.

### `removeTarget`

(

- `o`

)

Inherited from EventTarget: `event-custom/js/event-facade.js:489`

Removes a bubble target

#### Parameters:

- `o` EventTarget

  the target to remove

### `render`

() chainable

Inherited from View but overwritten in `app/js/app-base.js:266`

Renders this application by appending the `viewContainer` node to the `container` node if it isn't already a child of the container, and the `activeView` will be appended the view container, if it isn't already.

You should call this method at least once, usually after the initialization of your app instance so the proper DOM structure is setup and optionally append the container to the DOM if it's not there already.

You may override this method to customize the app's rendering, but you should expect that the `viewContainer`'s contents will be modified by the app for the purpose of rendering the `activeView` when it changes.

### `replace`

(

- `[url]`

)
chainable

Inherited from Router: `app/js/router.js:337`

Replaces the current browser history entry with a new one, and dispatches to the first matching route handler, if any.

Behind the scenes, this method uses HTML5 `pushState()` in browsers that support it (or the location hash in older browsers and IE) to change the URL.

The specified URL must share the same origin (i.e., protocol, host, and port) as the current page, or an error will occur.

#### Parameters:

- `[url]` String optional

  URL to set. This URL needs to be of the same origin as the current URL. This can be a URL relative to the router's `root` attribute. If no URL is specified, the page's current URL will be used.

#### Example:

    // Starting URL: http://example.com/

    router.replace('/path/');
    // New URL: http://example.com/path/

    router.replace('/path?foo=bar');
    // New URL: http://example.com/path?foo=bar

    router.replace('/');
    // New URL: http://example.com/

### `reset`

(

- `name`

)
Object chainable

Inherited from AttributeExtras: `attribute/js/AttributeExtras.js:89`

Resets the attribute (or all attributes) to its initial value, as long as the attribute is not readOnly, or writeOnce.

#### Parameters:

- `name` String

  Optional. The name of the attribute to reset. If omitted, all attributes are reset.

#### Returns:

Object: A reference to the host object.

### `route`

(

- `path`
- `callbacks`

)
chainable

Inherited from Router: `app/js/router.js:371`

Adds a route handler for the specified URL path.

The path parameter may be either a string or a regular expression. If it's a string, it may contain named parameters: `:param` will match any single part of a URL path (not including `/` characters), and `*param` will match any number of parts of a URL path (including `/` characters). These named parameters will be made available as keys on the `req.params` object that's passed to route handlers.

If the path parameter is a regex, all pattern matches will be made available as numbered keys on `req.params`, starting with `0` for the full match, then `1` for the first subpattern match, and so on.

Here's a set of sample routes along with URL paths that they match:

- Route: `/photos/:tag/:page`

  - URL: `/photos/kittens/1`, params: `{tag: 'kittens', page: '1'}`
  - URL: `/photos/puppies/2`, params: `{tag: 'puppies', page: '2'}`

- Route: `/file/*path`

  - URL: `/file/foo/bar/baz.txt`, params: `{path: 'foo/bar/baz.txt'}`
  - URL: `/file/foo`, params: `{path: 'foo'}`

Middleware: Routes also support an arbitrary number of callback functions. This allows you to easily reuse parts of your route-handling code with different route. This method is liberal in how it processes the specified `callbacks`, you can specify them as separate arguments, or as arrays, or both.

If multiple route match a given URL, they will be executed in the order they were added. The first route that was added will be the first to be executed.

Passing Control: Invoking the `next()` function within a route callback will pass control to the next callback function (if any) or route handler (if any). If a value is passed to `next()`, it's assumed to be an error, therefore stopping the dispatch chain, unless that value is: `"route"`, which is special case and dispatching will skip to the next route handler. This allows middleware to skip any remaining middleware for a particular route.

#### Parameters:

- `path` String | RegExp

  Path to match. May be a string or a regular expression.

- `callbacks` Array | Function | String multiple

  Callback functions to call whenever this route is triggered. These can be specified as separate arguments, or in arrays, or both. If a callback is specified as a string, the named function will be called on this router instance.

  - `req` Object

    Request object containing information about the request. It contains the following properties.

    - `params` Array | Object
      Captured parameters matched by the route path specification. If a string path was used and contained named parameters, then this will be a key/value hash mapping parameter names to their matched values. If a regex path was used, this will be an array of subpattern matches starting at index 0 for the full match, then 1 for the first subpattern match, and so on.
    - `path` String
      The current URL path.
    - `pendingCallbacks` Number
      Number of remaining callbacks the route handler has after this one in the dispatch chain.
    - `pendingRoutes` Number
      Number of matching routes after this one in the dispatch chain.
    - `query` Object
      Query hash representing the URL query string, if any. Parameter names are keys, and are mapped to parameter values.
    - `url` String
      The full URL.
    - `src` String
      What initiated the dispatch. In an HTML5 browser, when the back/forward buttons are used, this property will have a value of "popstate".
  - `res` Object

    Response object containing methods and information that relate to responding to a request. It contains the following properties.

    - `req` Object
      Reference to the request object.
  - `next` Function

    Function to pass control to the next callback or the next matching route if no more callbacks (middleware) exist for the current route handler. If you don't call this function, then no further callbacks or route handlers will be executed, even if there are more that match. If you do call this function, then the next callback (if any) or matching route handler (if any) will be called. All of these functions will receive the same `req` and `res` objects that were passed to this route (so you can use these objects to pass data along to subsequent callbacks and routes).

    - `[err]` String optional
      Optional error which will stop the dispatch chaining for this `req`, unless the value is `"route"`, which is special cased to jump skip past any callbacks for the current route and pass control the next route handler.

#### Example:

    router.route('/photos/:tag/:page', function (req, res, next) {
      Y.log('Current tag: ' + req.params.tag);
      Y.log('Current page number: ' + req.params.page);
    });

    // Using middleware.

    router.findUser = function (req, res, next) {
        req.user = this.get('users').findById(req.params.user);
        next();
    };

    router.route('/users/:user', 'findUser', function (req, res, next) {
        // The findUser middleware puts the user object on the req.
        Y.log('Current user:' req.user.get('name'));
    });

### `save`

(

- `[url]`

)
chainable

Inherited from Router: `app/js/router.js:498`

Saves a new browser history entry and dispatches to the first matching route handler, if any.

Behind the scenes, this method uses HTML5 `pushState()` in browsers that support it (or the location hash in older browsers and IE) to change the URL and create a history entry.

The specified URL must share the same origin (i.e., protocol, host, and port) as the current page, or an error will occur.

#### Parameters:

- `[url]` String optional

  URL to set. This URL needs to be of the same origin as the current URL. This can be a URL relative to the router's `root` attribute. If no URL is specified, the page's current URL will be used.

#### Example:

    // Starting URL: http://example.com/

    router.save('/path/');
    // New URL: http://example.com/path/

    router.save('/path?foo=bar');
    // New URL: http://example.com/path?foo=bar

    router.save('/');
    // New URL: http://example.com/

### `set`

(

- `name`
- `value`
- `[opts]`

)
Object chainable

Inherited from AttributeObservable but overwritten in `attribute/js/AttributeCore.js:410`

Sets the value of an attribute.

#### Parameters:

- `name` String

  The name of the attribute. If the current value of the attribute is an Object, dot notation can be used to set the value of a property within the object (e.g. `set("x.y.z", 5)`).

- `value` Any

  The value to set the attribute to.

- `[opts]` Object optional

  Optional data providing the circumstances for the change.

#### Returns:

Object: A reference to the host object.

### `setAttrs`

(

- `attrs`
- `[opts]`

)
Object chainable

Inherited from AttributeObservable but overwritten in `attribute/js/AttributeCore.js:729`

Sets multiple attribute values.

#### Parameters:

- `attrs` Object

  An object with attributes name/value pairs.

- `[opts]` Object optional

  Optional data providing the circumstances for the change.

#### Returns:

Object: A reference to the host object.

### `showView`

(

- `view`
- `[config]`
- `[options]`
- `[callback]`

)
chainable

Defined in `app/js/app-base.js:307`

Available since 3.5.0

Sets which view is active/visible for the application. This will set the app's `activeView` attribute to the specified `view`.

The `view` will be "attached" to this app, meaning it will be both rendered into this app's `viewContainer` node and all of its events will bubble to the app. The previous `activeView` will be "detached" from this app.

When a string-name is provided for a view which has been registered on this app's `views` object, the referenced metadata will be used and the `activeView` will be set to either a preserved view instance, or a new instance of the registered view will be created using the specified `config` object passed-into this method.

A callback function can be specified as either the third or fourth argument, and this function will be called after the new `view` becomes the `activeView`, is rendered to the `viewContainer`, and is ready to use.

#### Parameters:

- `view` String | View

  The name of a view defined in the `views` object, or a view instance which should become this app's `activeView`.

- `[config]` Object optional

  Optional configuration to use when creating a new view instance. This config object can also be used to update an existing or preserved view's attributes when `options.update` is `true`.

- `[options]` Object optional

  Optional object containing any of the following properties:

  - `[callback]` Function optional

    Optional callback function to call after new `activeView` is ready to use, the function will be passed:

    - `view` View
      A reference to the new `activeView`.
  - `[prepend=false]` Boolean optional

    Whether the `view` should be prepended instead of appended to the `viewContainer`.

  - `[render]` Boolean optional

    Whether the `view` should be rendered. Note: If no value is specified, a view instance will only be rendered if it's newly created by this method.

  - `[update=false]` Boolean optional

    Whether an existing view should have its attributes updated by passing the `config` object to its `setAttrs()` method. Note: This option does not have an effect if the `view` instance is created as a result of calling this method.

- `[callback]` Function optional

  Optional callback Function to call after the new `activeView` is ready to use. Note: this will override `options.callback` and it can be specified as either the third or fourth argument. The function will be passed the following:

  - `view` View

    A reference to the new `activeView`.

#### Example:

    var app = new Y.App({
        views: {
            usersView: {
                // Imagine that Y.UsersView has been defined.
                type: Y.UsersView
            }
        },

        users: new Y.ModelList()
    });

    app.route('/users/', function () {
        this.showView('usersView', {users: this.get('users')});
    });

    app.render();
    app.navigate('/uses/'); // => Creates a new Y.UsersView and shows it.

### `subscribe`

() deprecated

Inherited from EventTarget: `event-custom/js/event-target.js:336`

Deprecated: use on

subscribe to an event

### `toString`

() String

Inherited from BaseCore: `base/js/BaseCore.js:754`

Default toString implementation. Provides the constructor NAME and the instance guid, if set.

#### Returns:

String: String representation for this object

### `unsubscribe`

() deprecated

Inherited from EventTarget: `event-custom/js/event-target.js:459`

Deprecated: use detach

detach a listener

### `unsubscribeAll`

(

- `type`

)
deprecated

Inherited from EventTarget: `event-custom/js/event-target.js:480`

Deprecated: use detachAll

Removes all listeners from the specified event. If the event type is not specified, all listeners from all hosted custom events will be removed.

#### Parameters:

- `type` String

  The type, or name of the event

### `upgrade`

() Boolean

Inherited from Router: `app/js/router.js:532`

Upgrades a hash-based URL to an HTML5 URL if necessary. In non-HTML5 browsers, this method is a noop.

#### Returns:

Boolean: `true` if the URL was upgraded, `false` otherwise.

## Properties

### `_allowAdHocAttrs`

Boolean protected

Inherited from BaseCore but overwritten in `app/js/view.js:111`

Available since 3.5.0

This tells `Y.Base` that it should create ad-hoc attributes for config properties passed to View's constructor. This makes it possible to instantiate a view and set a bunch of attributes without having to subclass `Y.View` and declare all those attributes first.

Default: true

### `_dispatched`

Boolean protected

Inherited from Router: `app/js/router.js:64`

Whether or not `_dispatch()` has been called since this router was instantiated.

Default: undefined

### `_dispatching`

Boolean protected

Inherited from Router: `app/js/router.js:74`

Whether or not we're currently in the process of dispatching to routes.

Default: undefined

### `_historyEvents`

EventHandle protected

Inherited from Router: `app/js/router.js:83`

History event handle for the `history:change` or `hashchange` event subscription.

### `_html5`

Boolean protected

Inherited from Router: `app/js/router.js:92`

Cached copy of the `html5` attribute for internal use.

### `_NON_ATTRS_CFG`

Array protected static

Defined in `app/js/app-base.js:1020`

Available since 3.5.0

Properties that shouldn't be turned into ad-hoc attributes when passed to App's constructor.

### `_pjaxEvents`

EventHandle protected

Inherited from PjaxBase: `pjax/js/pjax-base.js:69`

Available since 3.5.0

Holds the delegated pjax-link click handler.

### `_ready`

Boolean protected

Inherited from Router: `app/js/router.js:100`

Whether or not the `ready` event has fired yet.

Default: undefined

### `_regexPathParam`

RegExp protected

Inherited from Router: `app/js/router.js:109`

Regex used to match parameter placeholders in route paths.

Subpattern captures:

1. Parameter prefix character. Either a `:` for subpath parameters that should only match a single level of a path, or `*` for splat parameters that should match any number of path levels.

2. Parameter name, if specified, otherwise it is a wildcard match.

### `_regexURL`

RegExp protected

Inherited from PjaxBase: `pjax/js/pjax-base.js:78`

Available since 3.5.0

Regex used to break up a URL string around the URL's path.

Subpattern captures:

1. Origin, everything before the URL's path-part.
2. The URL's path-part.
3. Suffix, everything after the URL's path-part.

### `_regexUrlOrigin`

RegExp protected

Inherited from Router: `app/js/router.js:136`

Regex that matches everything before the path portion of a URL (the origin). This will be used to strip this part of the URL from a string when we only want the path.

### `_regexUrlQuery`

RegExp protected

Inherited from Router: `app/js/router.js:126`

Regex that matches and captures the query portion of a URL, minus the preceding `?` character, and discarding the hash portion of the URL if any.

### `_viewInfoMap`

Object protected

Defined in `app/js/app-base.js:134`

Available since 3.5.0

Map of view instance id (via `Y.stamp()`) to view-info object in `views`.

This mapping is used to tie a specific view instance back to its metadata by adding a reference to the the related view info on the `views` object.

Default: {}

### `containerTemplate`

String

Inherited from View: `app/js/view.js:40`

Available since 3.5.0

Template for this view's container.

Default: "<div/>"

### `events`

Object

Inherited from View: `app/js/view.js:50`

Hash of CSS selectors mapped to events to delegate to elements matching those selectors.

CSS selectors are relative to the `container` element. Events are attached to the container, and delegation is used so that subscribers are only notified of events that occur on elements inside the container that match the specified selectors. This allows the container's contents to be re- rendered as needed without losing event subscriptions.

Event handlers can be specified either as functions or as strings that map to function names on this view instance or its prototype.

The `this` object in event handlers will refer to this view instance. If you'd prefer `this` to be something else, use `Y.bind()` to bind a custom `this` object.

Default: {}

#### Example:

    var view = new Y.View({
        events: {
            // Call this.toggle() whenever the element with the id
            // "toggle-button" is clicked.
            '#toggle-button': {click: 'toggle'},

            // Call this.hoverOn() when the mouse moves over any element
            // with the "hoverable" class, and this.hoverOff() when the
            // mouse moves out of any element with the "hoverable" class.
            '.hoverable': {
                mouseover: 'hoverOn',
                mouseout : 'hoverOff'
            }
        }
    });

### `name`

String deprecated

Inherited from BaseCore: `base/js/BaseCore.js:242`

Deprecated: Use this.constructor.NAME

The string used to identify the class of this object.

### `template`

Mixed

Inherited from View: `app/js/view.js:91`

Template for this view's contents.

This is a convenience property that has no default behavior of its own. It's only provided as a convention to allow you to store whatever you consider to be a template, whether that's an HTML string, a `Y.Node` instance, a Mustache template, or anything else your little heart desires.

How this template gets used is entirely up to you and your custom `render()` method.

Default: ''

### `views`

Object

Defined in `app/js/app-base.js:76`

Available since 3.5.0

Hash of view-name to metadata used to declaratively describe an application's views and their relationship with the app and its other views.

The view metadata is composed of Objects keyed to a view-name that can have any or all of the following properties:

- `type`: Function or a string representing the view constructor to use to create view instances. If a string is used, the constructor function is assumed to be on the `Y` object; e.g. `"SomeView"` -> `Y.SomeView`.

- `preserve`: Boolean for whether the view instance should be retained. By default, the view instance will be destroyed when it is no longer the `activeView`. If `true` the view instance will simply be `removed()` from the DOM when it is no longer active. This is useful when the view is frequently used and may be expensive to re-create.

- `parent`: String to another named view in this hash that represents the parent view within the application's view hierarchy; e.g. a `"photo"` view could have `"album"` has its `parent` view. This parent/child relationship is a useful cue for things like transitions.

- `instance`: Used internally to manage the current instance of this named view. This can be used if your view instance is created up-front, or if you would rather manage the View lifecycle, but you probably should just let this be handled for you.

If `views` are specified at instantiation time, the metadata in the `views` Object here will be used as defaults when creating the instance's `views`.

Every `Y.App` instance gets its own copy of a `views` object so this Object on the prototype will not be polluted.

Default: {}

#### Example:

    // Imagine that Y.UsersView and Y.UserView have been defined.
    var app = new Y.App({
        views: {
            users: {
                type    : Y.UsersView,
                preserve: true
            },

            user: {
                type  : Y.UserView,
                parent: 'users'
            }
        }
    });

## Attributes

### `activeView`

View readonly

Defined in `app/js/app-base.js:819`

Available since 3.5.0

The application's active/visible view.

This attribute is read-only, to set the `activeView` use the `showView()` method.

Default: null

#### Fires event `activeViewChange`

Fires when the value for the configuration attribute `activeView` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

### `container`

HTMLElement | Node | String

Inherited from View but overwritten in `app/js/app-base.js:837`

Container node which represents the application's bounding-box, into which this app's content will be rendered.

The container node serves as the host for all DOM events attached by the app. Delegation is used to handle events on children of the container, allowing the container's contents to be re-rendered at any time without losing event subscriptions.

The default container is the `<body>` Node, but you can override this in a subclass, or by passing in a custom `container` config value at instantiation time.

When `container` is overridden by a subclass or passed as a config option at instantiation time, it may be provided as a selector string, a DOM element, or a `Y.Node` instance. During initialization, this app's `create()` method will be called to convert the container into a `Y.Node` instance if it isn't one already and stamp it with the CSS class: `"yui3-app"`.

The container is not added to the page automatically. This allows you to have full control over how and when your app is actually rendered to the page.

Default: Y.one('body')

#### Fires event `containerChange`

Fires when the value for the configuration attribute `container` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

### `destroyed`

Boolean readonly

Inherited from BaseCore: `base/js/BaseCore.js:157`

Flag indicating whether or not this object has been through the destroy lifecycle phase.

Default: false

#### Fires event `destroyedChange`

Fires when the value for the configuration attribute `destroyed` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

### `html5`

Boolean

Inherited from Router but overwritten in `app/js/app-base.js:872`

Whether or not this browser is capable of using HTML5 history.

This value is dependent on the value of `serverRouting` and will default accordingly.

Setting this to `false` will force the use of hash-based history even on HTML5 browsers, but please don't do this unless you understand the consequences.

#### Fires event `html5Change`

Fires when the value for the configuration attribute `html5` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

### `initialized`

Boolean readonly

Inherited from BaseCore: `base/js/BaseCore.js:143`

Flag indicating whether or not this object has been through the init lifecycle phase.

Default: false

#### Fires event `initializedChange`

Fires when the value for the configuration attribute `initialized` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

### `linkSelector`

String | Function

Inherited from PjaxBase but overwritten in `app/js/app-base.js:891`

CSS selector string used to filter link click events so that only the links which match it will have the enhanced-navigation behavior of pjax applied.

When a link is clicked and that link matches this selector, navigating to the link's `href` URL using the enhanced, pjax, behavior will be attempted; and the browser's default way to navigate to new pages will be the fallback.

By default this selector will match all links on the page.

Default: "a"

#### Fires event `linkSelectorChange`

Fires when the value for the configuration attribute `linkSelector` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

### `navigateOnHash`

Boolean

Inherited from PjaxBase: `pjax/js/pjax-base.js:401`

Available since 3.5.0

Whether navigating to a hash-fragment identifier on the current page should be enhanced and cause the `navigate` event to fire.

By default Pjax allows the browser to perform its default action when a user is navigating within a page by clicking in-page links (e.g. `<a href="#top">Top of page</a>`) and does not attempt to interfere or enhance in-page navigation.

Default: false

#### Fires event `navigateOnHashChange`

Fires when the value for the configuration attribute `navigateOnHash` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

### `root`

String

Inherited from Router: `app/js/router.js:1336`

Absolute root path from which all routes should be evaluated.

For example, if your router is running on a page at `http://example.com/myapp/` and you add a route with the path `/`, your route will never execute, because the path will always be preceded by `/myapp`. Setting `root` to `/myapp` would cause all routes to be evaluated relative to that root URL, so the `/` route would then execute when the user browses to `http://example.com/myapp/`.

Default: `''`

#### Fires event `rootChange`

Fires when the value for the configuration attribute `root` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

### `routes`

Object[]

Inherited from Router: `app/js/router.js:1354`

Array of route objects.

Each item in the array must be an object with the following properties:

- `path`: String or regex representing the path to match. See the docs for the `route()` method for more details.

- `callbacks`: Function or a string representing the name of a function on this router instance that should be called when the route is triggered. An array of functions and/or strings may also be provided. See the docs for the `route()` method for more details.

This attribute is intended to be used to set routes at init time, or to completely reset all routes after init. To add routes after init without resetting all existing routes, use the `route()` method.

Default: `[]`

#### Fires event `routesChange`

Fires when the value for the configuration attribute `routes` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

### `scrollToTop`

Boolean

Inherited from PjaxBase: `pjax/js/pjax-base.js:419`

Available since 3.5.0

Whether the page should be scrolled to the top after navigating to a URL.

When the user clicks the browser's back button, the previous scroll position will be maintained.

Default: true

#### Fires event `scrollToTopChange`

Fires when the value for the configuration attribute `scrollToTop` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

### `serverRouting`

Boolean

Defined in `app/js/app-base.js:911`

Available since 3.5.0

Whether or not this application's server is capable of properly routing all requests and rendering the initial state in the HTML responses.

This can have three different values, each having particular implications on how the app will handle routing and navigation:

- `undefined`: The best form of URLs will be chosen based on the capabilities of the browser. Given no information about the server environmentm a balanced approach to routing and navigation is chosen.

  The server should be capable of handling full-path requests, since full-URLs will be generated by browsers using HTML5 history. If this is a client-side-only app the server could handle full-URL requests by sending a redirect back to the root with a hash-based URL, e.g:

      Request:     http://example.com/users/1
      Redirect to: http://example.com/#/users/1

- `true`: The server is fully capable of properly handling requests to all full-path URLs the app can produce.

  This is the best option for progressive-enhancement because it will cause all URLs to always have full-paths, which means the server will be able to accurately handle all URLs this app produces. e.g.

      http://example.com/users/1

  To meet this strict full-URL requirement, browsers which are not capable of using HTML5 history will make requests to the server resulting in full-page reloads.

- `false`: The server is not capable of properly handling requests to all full-path URLs the app can produce, therefore all routing will be handled by this App instance.

  Be aware that this will cause all URLs to always be hash-based, even in browsers that are capable of using HTML5 history. e.g.

      http://example.com/#/users/1

  A single-page or client-side-only app where the server sends a "shell" page with JavaScript to the client might have this restriction. If you're setting this to `false`, read the following:

Note: When this is set to `false`, the server will never receive the full URL because browsers do not send the fragment-part to the server, that is everything after and including the "#".

Consider the following example:

    URL shown in browser: http://example.com/#/users/1
    URL sent to server:   http://example.com/

You should feel bad about hurting our precious web if you forcefully set either `serverRouting` or `html5` to `false`, because you're basically punching the web in the face here with your lossy URLs! Please make sure you know what you're doing and that you understand the implications.

Ideally you should always prefer full-path URLs (not /#/foo/), and want full-page reloads when the client's browser is not capable of enhancing the experience using the HTML5 history APIs. Setting this to `true` is the best option for progressive-enhancement (and graceful-degradation).

Default: undefined

#### Fires event `serverRoutingChange`

Fires when the value for the configuration attribute `serverRouting` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

### `viewContainer`

HTMLElement | Node | String

Defined in `app/js/app-base.js:987`

Available since 3.5.0

The node into which this app's `views` will be rendered when they become the `activeView`.

The view container node serves as the container to hold the app's `activeView`. Each time the `activeView` is set via `showView()`, the previous view will be removed from this node, and the new active view's `container` node will be appended.

The default view container is a `<div>` Node, but you can override this in a subclass, or by passing in a custom `viewContainer` config value at instantiation time. The `viewContainer` may be provided as a selector string, DOM element, or a `Y.Node` instance (having the `viewContainer` and the `container` be the same node is also supported).

The app's `render()` method will stamp the view container with the CSS class `"yui3-app-views"` and append it to the app's `container` node if it isn't already, and any `activeView` will be appended to this node if it isn't already.

Default: Y.Node.create(this.containerTemplate)

#### Fires event `viewContainerChange`

Fires when the value for the configuration attribute `viewContainer` is changed. You can listen for the event using the `on` method if you wish to be notified before the attribute's value has changed, or using the `after` method if you wish to be notified after the attribute's value has changed.

#### Parameters:

- `e` EventFacade
  An Event Facade object with the following attribute-specific properties added:
  - `prevVal` Any
    The value of the attribute, prior to it being set.
  - `newVal` Any
    The value the attribute is to be set to.
  - `attrName` String
    The name of the attribute being set.
  - `subAttrName` String
    If setting a property within the attribute's value, the name of the sub-attribute property being set.

## Events

### `destroy`

Inherited from BaseObservable: `base/js/BaseObservable.js:151`

Lifecycle event for the destroy phase, fired prior to destruction. Invoking the preventDefault method on the event object provided to subscribers will prevent destruction from proceeding.

Subscribers to the "after" moment of this event, will be notified after destruction is complete (and as a result cannot prevent destruction).

#### Event Payload:

- `e` EventFacade

  Event object

### `init`

Inherited from BaseObservable: `base/js/BaseObservable.js:62`

Lifecycle event for the init phase, fired prior to initialization. Invoking the preventDefault() method on the event object provided to subscribers will prevent initialization from occuring.

Subscribers to the "after" momemt of this event, will be notified after initialization of the object is complete (and therefore cannot prevent initialization).

#### Event Payload:

- `e` EventFacade

  Event object, with a cfg property which refers to the configuration object passed to the constructor.

### `navigate`

Inherited from PjaxBase: `pjax/js/pjax-base.js:16`

Available since 3.5.0

Fired when navigating to a URL via Pjax.

When the `navigate()` method is called or a pjax link is clicked, this event will be fired if the browser supports HTML5 history and the router has a route handler for the specified URL.

This is a useful event to listen to for adding a visual loading indicator while the route handlers are busy handling the URL change.

#### Event Payload:

- `url` String

  The URL that the router will dispatch to its route handlers in order to fulfill the enhanced navigation "request".

- `[force=false]` Boolean optional

  Whether the enhanced navigation should occur even in browsers without HTML5 history.

- `[hash]` String optional

  The hash-fragment (including "#") of the `url`. This will be present when the `url` differs from the current URL only by its hash and `navigateOnHash` has been set to `true`.

- `[originEvent]` Event optional

  The event that caused the navigation. Usually this would be a click event from a "pjax" anchor element.

- `[replace]` Boolean optional

  Whether or not the current history entry will be replaced, or a new entry will be created. Will default to `true` if the specified `url` is the same as the current URL.

### `ready`

Inherited from Router: `app/js/router.js:24`

Fired when the router is ready to begin dispatching to route handlers.

You shouldn't need to wait for this event unless you plan to implement some kind of custom dispatching logic. It's used internally in order to avoid dispatching to an initial route if a browser history change occurs first.

#### Event Payload:

- `dispatched` Boolean

  `true` if routes have already been dispatched (most likely due to a history change).