simple javascript pubsub example

pubsubExample.js

var PubSub = (function(){
    var mapping = {};

    return {
        sub: function(eventName, callback, obj){
            callback = callback || _.noop;
            if(!_.isFunction(callback)){
                console.error("callback is not a function");
                return;
            }
            if(mapping[obj.__guid__ + ":" + eventName]){
                mapping[obj.__guid__ + ":" + eventName].push(callback);
            } else {
                mapping[obj.__guid__ + ":" + eventName] = [];
                mapping[obj.__guid__ + ":" + eventName].push(callback);
            }
        },

        pub: function(eventName, data){
            data = data || {};
            _.each(mapping[this.__guid__ + ":" + eventName], function(callback){
                callback(data);
            });
        }
    };
})(_);


// demo usage

var BaseObj = function(){
    this.__guid__ = Lybrate.Utils.GUID();
};
_.extend(BaseObj.prototype, PubSub);


var Foo = function(msg){
    BaseObj.call(this);
    console.log(this.__guid__);
    this.msg = msg;
};

Foo.prototype = Object.create(BaseObj.prototype);
_.extend(Foo.prototype, {
    printMsg: function(){
        console.log(this.msg);
    }
});

var Boo = function(msg){
    BaseObj.call(this);
    console.log(this.__guid__);
    this.msg = msg;
};

Boo.prototype = Object.create(BaseObj.prototype);
_.extend(Boo.prototype, {
    printMessage: function(){
        console.log(this.msg);
    }
});


// test
$(document).ready(function(){
    var foo = new Foo("Hello world!");
    var boo = new Boo("Hi there!");
    var foo2 = new Foo("Foo2 here!");
    var boo2 = new Boo("Boo2 here!");

    foo.sub("change", function(data){
        console.log("foo heard change");
        console.log(data);
    }, boo);

    foo.sub("change", function(data){
        console.log("foo heard change");
        console.log(data);
    }, boo2);

    boo.sub("change", function(data){
        console.log("boo heard change");
        console.log(data);
    }, foo);

    boo.sub("change", function(data){
        console.log("boo heard change");
        console.log(data);
    }, foo2);


    foo2.sub("change", function(data){
        console.log("foo2 heard change");
        console.log(data);
    }, boo2);

    boo2.sub("change", function(data){
        console.log("boo2 heard change");
        console.log(data);
    }, foo2);

    window.setTimeout(function(){

        foo.pub("change", "foo changed");
        boo.pub("change", "boo changed");
    }, 2000);

    window.setTimeout(function(){
        foo2.pub("change", "foo2 changed");
        boo2.pub("change", "boo2 changed");
    }, 4000);


});