pubsub prototype pattern js

pubsub

var PubSub = function() {};


//this will store the callback into the topics array
PubSub.prototype.subscribe = function( topic, callback, context) {
    context = context || this;
    this._topics = this._topics || {};
    this._topics[topic] = this._topics.topic || [];
    this._topics[topic].push({ "content", context, "callback", callback });
}

//takes the topic's call back and calls with with the proper context
PubSub.prototype.publish = function( topic ){
    context = context || this;
    this._topics[topic].forEach(function(subscription) {
            subscription.callback.callback(subscription.context);
        }
}


//topics

var Tags = function(){};
Tags.prototype.listTags = function() {
    this._tags = this._tags || [ ];
    return this._tags;
}

Tags.prototype.addTag = function(tag){
    this._tags = this._tags || [ ];
    this._tags.push(tag);
    this.publish && this.publish("Tag Added");
    }
Tags.prototype.removeTag = function(){
    this._tags = this._tags || [ ];
    
    var index = this._tags.indexOf(tag);
    this._tags = this._tags.splice(index, 1); 
    }

Tags.prototype.countTags = function(){
    return this._tags.length;
    }