Simple extend.

core.extend.js

/**
 * Extends old object with new (returns a copy)
 *
 * @author   Hector Menendez <[email protected]>
 * @created  2011/NOV/21 17:41
 * @updated  2012/MAR/20 01:13  Added support for unlimited arguments.
 *                              Native properties will be ignored.
 */
core.extend = function(){
	var args = private.arguments(arguments); // sanitize args
	if (!args.length) return core.error('Missing objects to extend','extend');
	// first argument will be considered the original, we won't rewrite it.
	var orig = args.shift();
	if (typeof orig != 'object')
		return core.error('First argument needs to be an object.','extend');
	var i,prop;
	for (i in args){
		if (typeof args[i] != 'object')
			return core.error('All arguments need to be objects.','extend');
		// traverse properties of each object argument and copy them.
		for (prop in args[i]){
			if (!args[i].hasOwnProperty(prop)) continue; // ignore native props
			orig[prop] = args[i][prop];
		}
	}
	// make a copy of original object
	var copy = {};
	for (i in orig) {
		if (!orig.hasOwnProperty(i)) continue; // ignore native props
		copy[i] = orig[i];
	}
	return copy;
}