extends objects, similar in functionality to $.extend or _.extend

extend.es5.js

// jquery style `extend` work in ES5 compatible envs

var extend = function (obj) {
	var args = Array.prototype.slice.call(arguments, 1);
	args.forEach( function (source) {
		for (var prop in source) 
			if (source.hasOwnProperty(prop)) obj[prop] = source[prop];
	});
	return obj;
};

extend.js

// jquery style `extend` function

var extend = function (obj) {
	var args = Array.prototype.slice.call(arguments, 1),
		i,k,j, n = args.length, o;
	for (i = 0; i < n; i ++) (function (j) {
		o = args[i];
		for (var k in o) 
			if (o.hasOwnProperty(k)) (function(key, value) {
				obj[key] = value;
			})(k, o[k]);
	})(i);
	return obj;
};

extend.recursive.js

// lightweight recursive extend

var recursiveExtend = function () {
	var result = {},
		args = Array.prototype.slice.call(arguments),
		mergeRecursive = function (obj1, obj2) {
			for (var p in obj2) {
				try {
					if ( obj2[p].constructor==Object ) {
						obj1[p] = mergeRecursive(obj1[p], obj2[p]);
					}
					else {
						obj1[p] = obj2[p];
					}
				} 
				catch(e) {
					obj1[p] = obj2[p];
				}
			}
			return obj1;
		};

	args.forEach( function (obj) {
		mergeRecursive(result, obj);
	});
	return result;
};