File yui3/src/yui/js/yui-object.js
/**
* The YUI module contains the components required for building the YUI
* seed file. This includes the script loading mechanism, a simple queue,
* and the core utilities for the library.
* @module yui
* @submodule yui-base
*/
/**
* Adds utilities to the YUI instance for working with objects.
*
* @class Object
*/
var Lang = Y.Lang,
hasOwn = Object.prototype.hasOwnProperty,
UNDEFINED, // <-- Note the comma. We're still declaring vars.
/**
* Returns a new object that uses _obj_ as its prototype. This method wraps the
* native ES5 `Object.create()` method if available, but doesn't currently
* pass through `Object.create()`'s second argument (properties) in order to
* ensure compatibility with older browsers.
*
* @method ()
* @param {Object} obj Prototype object.
* @return {Object} New object using _obj_ as its prototype.
* @static
*/
O = Y.Object = Lang._isNative(Object.create) ? function (obj) {
// We currently wrap the native Object.create instead of simply aliasing it
// to ensure consistency with our fallback shim, which currently doesn't
// support Object.create()'s second argument (properties). Once we have a
// safe fallback for the properties arg, we can stop wrapping
// Object.create().
return Object.create(obj);
} : (function () {
// Reusable constructor function for the Object.create() shim.
function F() {}
// The actual shim.
return function (obj) {
F.prototype = obj;
return new F();
};
}()),
/**
* Property names that IE doesn't enumerate in for..in loops, even when they
* should be enumerable. When `_hasEnumBug` is `true`, it's necessary to
* manually enumerate these properties.
*
* @property _forceEnum
* @type String[]
* @protected
* @static
*/
forceEnum = O._forceEnum = [
'hasOwnProperty',
'isPrototypeOf',
'propertyIsEnumerable',
'toString',
'toLocaleString',
'valueOf'
],
/**
* `true` if this browser has the JScript enumeration bug that prevents
* enumeration of the properties named in the `_forceEnum` array, `false`
* otherwise.
*
* See:
* - <https://developer.mozilla.org/en/ECMAScript_DontEnum_attribute#JScript_DontEnum_Bug>
* - <http://whattheheadsaid.com/2010/10/a-safer-object-keys-compatibility-implementation>
*
* @property _hasEnumBug
* @type Boolean
* @protected
* @static
*/
hasEnumBug = O._hasEnumBug = !{valueOf: 0}.propertyIsEnumerable('valueOf'),
/**
* `true` if this browser incorrectly considers the `prototype` property of
* functions to be enumerable. Currently known to affect Opera 11.50 and Android 2.3.x.
*
* @property _hasProtoEnumBug
* @type Boolean
* @protected
* @static
*/
hasProtoEnumBug = O._hasProtoEnumBug = (function () {}).propertyIsEnumerable('prototype'),
/**
* Returns `true` if _key_ exists on _obj_, `false` if _key_ doesn't exist or
* exists only on _obj_'s prototype. This is essentially a safer version of
* `obj.hasOwnProperty()`.
*
* @method owns
* @param {Object} obj Object to test.
* @param {String} key Property name to look for.
* @return {Boolean} `true` if _key_ exists on _obj_, `false` otherwise.
* @static
*/
owns = O.owns = function (obj, key) {
return !!obj && hasOwn.call(obj, key);
}; // <-- End of var declarations.
/**
* Alias for `owns()`.
*
* @method hasKey
* @param {Object} obj Object to test.
* @param {String} key Property name to look for.
* @return {Boolean} `true` if _key_ exists on _obj_, `false` otherwise.
* @static
*/
O.hasKey = owns;
/**
* Returns an array containing the object's enumerable keys. Does not include
* prototype keys or non-enumerable keys.
*
* Note that keys are returned in enumeration order (that is, in the same order
* that they would be enumerated by a `for-in` loop), which may not be the same
* as the order in which they were defined.
*
* This method is an alias for the native ES5 `Object.keys()` method if
* available and non-buggy. The Opera 11.50 and Android 2.3.x versions of
* `Object.keys()` have an inconsistency as they consider `prototype` to be
* enumerable, so a non-native shim is used to rectify the difference.
*
* @example
*
* Y.Object.keys({a: 'foo', b: 'bar', c: 'baz'});
* // => ['a', 'b', 'c']
*
* @method keys
* @param {Object} obj An object.
* @return {String[]} Array of keys.
* @static
*/
O.keys = Lang._isNative(Object.keys) && !hasProtoEnumBug ? Object.keys : function (obj) {
if (!Lang.isObject(obj)) {
throw new TypeError('Object.keys called on a non-object');
}
var keys = [],
i, key, len;
if (hasProtoEnumBug && typeof obj === 'function') {
for (key in obj) {
if (owns(obj, key) && key !== 'prototype') {
keys.push(key);
}
}
} else {
for (key in obj) {
if (owns(obj, key)) {
keys.push(key);
}
}
}
if (hasEnumBug) {
for (i = 0, len = forceEnum.length; i < len; ++i) {
key = forceEnum[i];
if (owns(obj, key)) {
keys.push(key);
}
}
}
return keys;
};
/**
* Returns an array containing the values of the object's enumerable keys.
*
* Note that values are returned in enumeration order (that is, in the same
* order that they would be enumerated by a `for-in` loop), which may not be the
* same as the order in which they were defined.
*
* @example
*
* Y.Object.values({a: 'foo', b: 'bar', c: 'baz'});
* // => ['foo', 'bar', 'baz']
*
* @method values
* @param {Object} obj An object.
* @return {Array} Array of values.
* @static
*/
O.values = function (obj) {
var keys = O.keys(obj),
i = 0,
len = keys.length,
values = [];
for (; i < len; ++i) {
values.push(obj[keys[i]]);
}
return values;
};
/**
* Returns the number of enumerable keys owned by an object.
*
* @method size
* @param {Object} obj An object.
* @return {Number} The object's size.
* @static
*/
O.size = function (obj) {
try {
return O.keys(obj).length;
} catch (ex) {
return 0; // Legacy behavior for non-objects.
}
};
/**
* Returns `true` if the object owns an enumerable property with the specified
* value.
*
* @method hasValue
* @param {Object} obj An object.
* @param {any} value The value to search for.
* @return {Boolean} `true` if _obj_ contains _value_, `false` otherwise.
* @static
*/
O.hasValue = function (obj, value) {
return Y.Array.indexOf(O.values(obj), value) > -1;
};
/**
* Executes a function on each enumerable property in _obj_. The function
* receives the value, the key, and the object itself as parameters (in that
* order).
*
* By default, only properties owned by _obj_ are enumerated. To include
* prototype properties, set the _proto_ parameter to `true`.
*
* @method each
* @param {Object} obj Object to enumerate.
* @param {Function} fn Function to execute on each enumerable property.
* @param {mixed} fn.value Value of the current property.
* @param {String} fn.key Key of the current property.
* @param {Object} fn.obj Object being enumerated.
* @param {Object} [thisObj] `this` object to use when calling _fn_.
* @param {Boolean} [proto=false] Include prototype properties.
* @return {YUI} the YUI instance.
* @chainable
* @static
*/
O.each = function (obj, fn, thisObj, proto) {
var key;
for (key in obj) {
if (proto || owns(obj, key)) {
fn.call(thisObj || Y, obj[key], key, obj);
}
}
return Y;
};
/**
* Executes a function on each enumerable property in _obj_, but halts if the
* function returns a truthy value. The function receives the value, the key,
* and the object itself as paramters (in that order).
*
* By default, only properties owned by _obj_ are enumerated. To include
* prototype properties, set the _proto_ parameter to `true`.
*
* @method some
* @param {Object} obj Object to enumerate.
* @param {Function} fn Function to execute on each enumerable property.
* @param {mixed} fn.value Value of the current property.
* @param {String} fn.key Key of the current property.
* @param {Object} fn.obj Object being enumerated.
* @param {Object} [thisObj] `this` object to use when calling _fn_.
* @param {Boolean} [proto=false] Include prototype properties.
* @return {Boolean} `true` if any execution of _fn_ returns a truthy value,
* `false` otherwise.
* @static
*/
O.some = function (obj, fn, thisObj, proto) {
var key;
for (key in obj) {
if (proto || owns(obj, key)) {
if (fn.call(thisObj || Y, obj[key], key, obj)) {
return true;
}
}
}
return false;
};
/**
* Retrieves the sub value at the provided path,
* from the value object provided.
*
* @method getValue
* @static
* @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,
* undefined if the source is not an object. Returns the source object
* if an empty path is provided.
*/
O.getValue = function(o, path) {
if (!Lang.isObject(o)) {
return UNDEFINED;
}
var i,
p = Y.Array(path),
l = p.length;
for (i = 0; o !== UNDEFINED && i < l; i++) {
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
* @static
* @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 i,
p = Y.Array(path),
leafIdx = p.length - 1,
ref = o;
if (leafIdx >= 0) {
for (i = 0; ref !== UNDEFINED && i < leafIdx; i++) {
ref = ref[p[i]];
}
if (ref !== UNDEFINED) {
ref[p[i]] = val;
} else {
return UNDEFINED;
}
}
return o;
};
/**
* Returns `true` if the object has no enumerable properties of its own.
*
* @method isEmpty
* @param {Object} obj An object.
* @return {Boolean} `true` if the object is empty.
* @static
* @since 3.2.0
*/
O.isEmpty = function (obj) {
return !O.keys(Object(obj)).length;
};