Collection Native for MooTools

Collection.js

function Collection(list, build){
	this.list = $splat(list || []);
	this.length = this.list.length;
	this.build = build || true;
	if (this.build) this.rebuild();
}

new Native({name: 'Collection', initialize: Collection, generics: false});

(function() {

var proto = Array.prototype;
var destructive = {pop:'remove', push:'add', shift:'remove', unshift:'add', reverse: 'change', splice: 'change'};

// Some browsers don't iterate over natives, so brute force is required.
var natives = ["indexOf", "join", "lastIndexOf", "pop", "push", "reverse", "shift", "slice", "sort", "splice", "unshift"];
natives.each(function(item){
	Collection.implement(item, function(){
		var destroyed = destructive[item];
		if (!!destroyed) this.fireEvent(destroyed, proto.slice.call(arguments))
		var results = proto[item].apply(this.list, arguments);
		if (!!destroyed) this.clean().rebuild().length = this.list.length;
		return results instanceof Array ? new Collection(results) : results;
	});
});

/*
for (var i in proto){
	if (proto[i] instanceof Function) (function(item){
		Collection.implement(i, function(){
			this.fireEvent(item, proto.slice.call(arguments));
			var results = proto[item].apply(this.list, arguments);
			return results instanceof Array ? new Collection(results) : results;
		});
	})(i);
}
*/


Collection.implement($extend({

	toString: function(){
		return this.list.toString();
	},

	valueOf: function(){
		return this.list.valueOf();
	},

	rebuild: function(){
		if (!this.build) return this;
		for (var x = this.list.length; x--;){
			this[x] = this.list[x];
		}
		return this;
	},

	clean: function(){
		if (!this.build) return this;
		for (var i in this){
			if (this.hasOwnProperty(i) && (/^([\d])+$/).test(i)) delete this[i];
		}
		return this;
	},

	concat: function(){
		var args = proto.slice.call(arguments);
		args = args.map(function(i){ return i instanceof Collection ? i.list : i; });
		var results = proto.concat.apply(this.list, args);
		return results instanceof Array ? new Collection(results) : results;
	}

}, new Events));

})();