SOURCE

function mixin(receiver, supplier) {

    for (var property in supplier) {

        if (supplier.hasOwnProperty(property)) {

            receiver[property] = supplier[property];
        }

    }

}

function EventTarget() {

}

EventTarget.prototype = {

    constructor: EventTarget,

    addListener: function (type, listener) {

        if (!this.hasOwnProperty('_listeners')) {

            this._listeners = [];
        }



        if (typeof this._listeners[type]=="undefined") {

            this._listeners[type] = [];
        }


        this._listeners[type].push(listener);
    },

    fire: function (event) {

 
        if (!event.target) {

            event.target = this;
        }

        if (!event.type) {

            throw new Error('event.type missing');
        }

        
        if (this._listeners && this._listeners[event.type] instanceof Array) {
        
            var listeners = this._listeners[event.type];
       
            for (var i = 0, len = listeners.length; i < len; i++) {
               
                listeners[i].call(this, event);
            }
        }

    },


    removeListener: function (type, listener) {

        if (this._listeners && Array.isArray(this._listeners[type])) {



            var listeners = this._listeners[type];
            for (var i = 0, len = listeners.length; i < len; i++) {
                if (listeners[i] === listener) {
                    listeners.splice(i, 1);

                    return;
                }
            }
        }

    }

}

var target = new EventTarget();
target.addListener("message", function (event) {

    console.info("Message is "+event.data);
});

target.fire( {

        'type':'message',
        'data':'Kong desong'

});