events.js

/**
 * Custom Event
 *
 * @example
 * <pre>
 * 	function Foo() {}
 * 	Foo.prototype.render = function() {
 *  	this.trigger('rendered');
 *  };
 *  Events.mixin(Foo);
 *  var foo = new Foo();
 *  foo.on('rendered', function(){
 *  	alert('rendered triggerd!');
 * 	});
 * 	foo.render();
 * </pre>
 * @module Events
 * @author wiky
 * @verson 0.0.2
 */

function Events() {}

Events.prototype = {
	/**
	 * create and bind an event to this Object.
	 *
	 * @param  {String} type    Event type
	 * @param  {Function} handler Event handler
	 * @param  {Object} [params]
	 * @param  {Object} [scope]
	 * @return {Boolean}		Is bind success
	 */
	on: function(type, handler, scope) {
		var ret = false;

		this._events = this._events || {};
		this._events[type] = this._events[type] || [];
		if (typeof type === 'string' && typeof handler === 'function') {
			this._events[type].push({
				fn: handler,
				scope: scope || this
			});
			ret = true;
		}

		return ret;
	},
	/**
	 * off an event from this Object.
	 *
	 * @param  {String} type    Event type
	 * @param  {Function} [handler] [description]
	 * @return {Boolean}         Is off success
	 */
	off: function(type, handler) {
		var arr, ret = false;

		this._events = this._events || {};
		arr = this._events[type];
		if (arr instanceof Array) {
			if (typeof handler === 'function') {
				this._events[type] = arr.filter(function(o) {
					return o && o.fn !== handler;
				});
			} else {
				delete this._events[type];
			}
			ret = true;
		}

		return ret;
	},
	/**
	 * trigger the custom event.
	 *
	 * @param  {String} type Event type
	 * @param  {Object} [args] Event arguments
	 * @return {Boolean}	Break out or not
	 */
	trigger: function() {
		var arr, args, type;
        args = ([]).slice.call(arguments);
        type = args.shift();
		this._events = this._events || {};
		arr = this._events[type];
		if (arr instanceof Array) {
			arr.forEach(function(o) {
				if(o && o.fn) {
					o.fn.apply(o.scope || this, args);
				}
			});
		}
	}
};