# Yahoo! UI Library

### yui 3.0.0b1

Yahoo! UI Library > yui > yui-object.js (source view)
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    (function() {

    /**
     * Adds the following Object utilities to the YUI instance
     * @class Object
     */

    /**
     * Y.Object(o) returns a new object based upon the supplied object.
     * @TODO Use native Object.create() when available
     * @method ()
     * @static
     * @param o the supplier object
     * @return {Object} the new object
     */
    Y.Object = function(o) {
        var F = function() {};
        F.prototype = o;
        return new F();
    };

    var O = Y.Object,

    UNDEFINED = undefined,

    /**
     * Extracts the keys, values, or size from an object
     *
     * @method _extract
     * @param o the object
     * @param what what to extract (0: keys, 1: values, 2: size)
     * @return {boolean|Array} the extracted info
     * @static
     * @private
     */
    _extract = function(o, what) {
        var count = (what === 2), out = (count) ? 0 : [], i;

        for (i in o) {
            if (count) {
                out++;
            } else {
                if (o.hasOwnProperty(i)) {
                    out.push((what) ? o[i] : i);
                }
            }
        }

        return out;
    };

    /**
     * Returns an array containing the object's keys
     * @TODO use native Object.keys() if available
     * @method keys
     * @static
     * @param o an object
     * @return {string[]} the keys
     */
    O.keys = function(o) {
        return _extract(o);
    };

    /**
     * Returns an array containing the object's values
     * @TODO use native Object.values() if available
     * @method values
     * @static
     * @param o an object
     * @return {Array} the values
     */
    O.values = function(o) {
        return _extract(o, 1);
    };

    /**
     * Returns the size of an object
     * @TODO use native Object.size() if available
     * @method size
     * @static
     * @param o an object
     * @return {int} the size
     */
    O.size = function(o) {
        return _extract(o, 2);
    };

    /**
     * Returns true if the object contains a given key
     * @method hasKey
     * @static
     * @param o an object
     * @param k the key to query
     * @return {boolean} true if the object contains the key
     */
    O.hasKey = function(o, k) {
        // return (o.hasOwnProperty(k));
        return (k in o);
    };

    /**
     * Returns true if the object contains a given value
     * @method hasValue
     * @static
     * @param o an object
     * @param v the value to query
     * @return {boolean} true if the object contains the value
     */
    O.hasValue = function(o, v) {
        return (Y.Array.indexOf(O.values(o), v) > -1);
    };

    /**
     * Determines whether or not the property was added
     * to the object instance.  Returns false if the property is not present
     * in the object, or was inherited from the prototype.
     *
     * @deprecated Safari 1.x support has been removed, so this is simply a
     * wrapper for the native implementation.  Use the native implementation
     * directly instead.
     *
     * @TODO Remove in B1
     *
     * @method owns
     * @static
     * @param o {any} The object being testing
     * @param p {string} the property to look for
     * @return {boolean} true if the object has the property on the instance
     */
    O.owns = function(o, k) {
        return (o.hasOwnProperty(k));
    };

    /**
     * Executes a function on each item. The function
     * receives the value, the key, and the object
     * as paramters (in that order).
     * @method each
     * @static
     * @param o the object to iterate
     * @param f {function} the function to execute
     * @param c the execution context
     * @param proto {boolean} include proto
     * @return {YUI} the YUI instance
     */
    O.each = function (o, f, c, proto) {
        var s = c || Y, i;

        for (i in o) {
            if (proto || o.hasOwnProperty(i)) {
                f.call(s, o[i], i, o);
            }
        }
        return Y;
    };

    /**
     * Retrieves the sub value at the provided path,
     * from the value object provided.
     *
     * @method getValue
     * @param o The object from which to extract the property value
     * @param path {Array} A path array, specifying the object traversal path
     * from which to obtain the sub value.
     * @return {Any} The value stored in the path, undefined if not found.
     * Returns the source object if an empty path is provided.
     */
    O.getValue = function (o, path) {
        var p=Y.Array(path), l=p.length, i;

        for (i=0; o !== UNDEFINED && i < l; i=i+1) {
            o = o[p[i]];
        }

        return o;
    };

    /**
     * Sets the sub-attribute value at the provided path on the
     * value object.  Returns the modified value object, or
     * undefined if the path is invalid.
     *
     * @method setValue
     * @param o             The object on which to set the sub value.
     * @param path {Array}  A path array, specifying the object traversal path
     *                      at which to set the sub value.
     * @param val {Any}     The new value for the sub-attribute.
     * @return {Object}     The modified object, with the new sub value set, or
     *                      undefined, if the path was invalid.
     */
    O.setValue = function(o, path, val) {

        var p=Y.Array(path), leafIdx=p.length-1, i, ref=o;

        if (leafIdx >= 0) {
            for (i=0; ref !== UNDEFINED && i < leafIdx; i=i+1) {
                ref = ref[p[i]];
            }

            if (ref !== UNDEFINED) {
                ref[p[i]] = val;
            } else {
                return UNDEFINED;
            }
        }

        return o;
    };

    })();

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