deep extend or copy an object

object.extend.js

(function () {
	var objStr = '[object Object]';
	//var arrStr = '[object Array]';

	//var isArray = function (a) {
	//	return Object.prototype.toString.call(a) === arrStr;
	//};

	var isObject = function (o) {
		return Object.prototype.toString.call(o) === objStr;
	};


	var objExtend = function (a, b, deep) {
		var key, val;
		deep = typeof deep === 'boolean';

		for (key in b) {
			if (b.hasOwnProperty(key)) {
				a[key] = (deep && isObject(b[key])) ? objExtend(a[key] && isObject(a[key]) ? a[key] : {}, b[key]) : b[key];
			}
		}

		return a;
	};


	/**
	 * @param o1		{Object} the Object to be extended
	 * @param o2		{Object} the Object that holds the properties/methods
	 * which o1 should be extended with;
	 * @param options	{Object} takes 2 properties: copy and deep
	 *
	 * select copy and a extended copy of the o1 Object will be returned
	 * instread of the extended o1 object;
	 *
	 * select deep for a deep extension / copy
	 */

	var extend = function (o1, o2, options) {
		options = options || {};
		var copy = !!options.copy,
		o = !copy ? o1 : objExtend({}, o1, true);
		return objExtend(o, o2, !!options.deep);
	}; 
}());