JS шаблон слушатель

observer.js

Event = function() {
    this._observers = [];
}
Event.prototype = {
    raise: function (data) {
        for (var i in this._observers) {
            var item = this._observers[i];
            item.observer.call(item.context, data);
        }
    },
    subscribe: function (observer, context) {
        var ctx = context || null;
        this._observers.push({ observer: observer, context: ctx });
    },
    unsubscribe: function (observer, context ) {
        for (var i in this._observers) {
            if ( this._observers[i].observer == observer &&
                 this._observers[i].context == context
             ) {
                delete this._observers[i];
            }
        }
    }
} 
 
 
var someEvent = new Event();
someEvent.subscribe(function ( data ) { console.log("wohoooooo " + data ) });
 
var someObject = {
    _topSecretInfo: 42,
    observerFunction: function () { console.log("Top Secret:" + this._topSecretInfo) }
}
someEvent.subscribe(someObject.observerFunction, someObject); 
someEvent.raise("yeaah!");
someEvent.raise();

//N2
var publisher = {
    subscribers: []
    
    , on: function(type, fn, context) {
        type = type || 'any';
        fn = typeof fn === 'function' ? fn : context[fn];
        
        if(typeof this.subscribers[type] === 'undefined') {
            this.subscribers[type] = [];
        }
        this.subscribers[type].push({fn: fn, context: context || this});
    }
    
    , remove: function(type, fn, context) {
        this.visitSubscribers('unsubscribe', type, fn, context);
    }
    
    , fire: function(type, publication) {
        this.visitSubscribers('publish', type, publication);
    }
    
    , visitSubscribers: function(action, type, arg, context) {
        var
            pubtype = type || 'any'
            , subscribers = this.subscribers[pubtype]
            , i
            , max = subscribers ? subscribers.length : 0
        ;
        
        for(i = 0; i < max; i += 1) {
            if(action === 'publish') {
                subscribers[i].fn.call(subscribers[i].context, arg);
            } else {
                if(subscribers[i].fn === arg && subscribers[i].context === context) {
                    subscribers.splice(i, 1);
                }
            }
        }
    }
}