'use strict';

var Utils = require( './utils' );

//#build

// The prototype methods are stored in a different object
// and applied as non enumerable properties later
var emitterProto = {
	on: function( eventName, listener, once ){
		var listeners = this._events[ eventName ] || [];

		listeners.push({ callback: listener, once: once});
		this._events[ eventName ] =  listeners;

		return this;
	},

	once: function( eventName, listener ){
		this.on( eventName, listener, true );
	},

	off: function( eventName, listener ){
		if( typeof eventName == 'undefined' ){
			this._events = {};
		}
		else if( typeof listener == 'undefined' ) {
			this._events[ eventName ] = [];
		}
		else {
			var listeners = this._events[ eventName ] || [],
				i
			;

			for (i = listeners.length - 1; i >= 0; i--) {
				if( listeners[i].callback === listener )
					listeners.splice( i, 1 );
			}
		}

		return this;
	},

	trigger: function( eventName ){
		var args = [].slice.call( arguments, 1 ),
			listeners = this._events[ eventName ] || [],
			onceListeners = [],
			i, listener
		;

		// Call listeners
		for (i = 0; i < listeners.length; i++) {
			listener = listeners[i];

			if( listener.callback )
				listener.callback.apply( null, args );
			else {
				// If there is not a callback, remove!
				listener.once = true;
			}

			if( listener.once )
				onceListeners.push( i );
		}

		// Remove listeners marked as once
		for( i = onceListeners.length - 1; i >= 0; i-- ){
			listeners.splice( onceListeners[i], 1 );
		}

		return this;
	}
};

// Methods are not enumerable so, when the stores are
// extended with the emitter, they can be iterated as
// hashmaps
var Emitter = Utils.createNonEnumerable( emitterProto );
//#build

module.exports = Emitter;

@@ -436,16 +436,23 @@
 er )%7B%0A%09%09
+return 
 this.on(

Update emitter.js