yui-object.js revision 7cd8fe832d4f91bed468c7498ff957c446f90aaa
/**
* 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
*/
(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,
owns = function(o, k) {
return o && o.hasOwnProperty && o.hasOwnProperty(k);
// return Object.prototype.hasOwnProperty.call(o, k);
},
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 (owns(o, i)) {
if (count) {
out++;
} else {
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 = owns;
/**
* 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.
*
* @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 = owns;
/**
* Executes a function on each item. The function
* receives the value, the key, and the object
* as parameters (in that order).
* @method each
* @static
* @param o the object to iterate
* @param f {Function} the function to execute on each item. The function
* receives three arguments: the value, the the key, the full object.
* @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 || owns(o, i)) {
f.call(s, o[i], i, o);
}
}
return Y;
};
/**
* Executes a function on each item, but halts if the
* function returns true. The function
* receives the value, the key, and the object
* as paramters (in that order).
* @method some
* @static
* @param o the object to iterate
* @param f {Function} the function to execute on each item. The function
* receives three arguments: the value, the the key, the full object.
* @param c the execution context
* @param proto {boolean} include proto
* @return {boolean} true if any execution of the function returns true, false otherwise
*/
O.some = function (o, f, c, proto) {
var s = c || Y, i;
for (i in o) {
if (proto || owns(o, i)) {
if (f.call(s, o[i], i, o)) {
return true;
}
}
}
return false;
};
/**
* 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,
* undefined if the source is not an object. Returns the source object
* if an empty path is provided.
*/
O.getValue = function (o, path) {
if (!Y.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
* @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 properties of its own
* @method isEmpty
* @return {boolean} true if the object is empty
* @since 3.2.0
*/
O.isEmpty = function(o) {
for (var i in o) {
if (owns(o, i)) {
return false;
}
}
return true;
};
})();