Extending Objects

extended.js

var EventEmitter = require('events').EventEmitter;

var MyNewEmitter = function () {
   EventEmitter.call(this);
   var that = this;
   setInterval(function () {
      that.emit('myEvent');
   }, 1000);
};

MyNewEmitter.prototype = Object.create(EventEmitter.prototype);
MyNewEmitter.prototype.constructor = MyNewEmitter;

MyNewEmitter.prototype.on = function (eventName, callback) {
   console.log('Hey! Someone subscribed to ' + eventName);
   EventEmitter.prototype.on.call(this, eventName, callback);
};

var MyNextNewerEmitter = function () {
   MyNewEmitter.call(this);
};

MyNextNewerEmitter.prototype = Object.create(EventEmitter.prototype);
MyNextNewerEmitter.prototype.constructor = MyNextNewerEmitter;

MyNextNewerEmitter.prototype.on = function (eventName, callback) {
   console.log('Another layer of indirection');
   MyNewEmitter.prototype.on.call(this, eventName, callback);
};

var emitter = new MyNextNewerEmitter();

emitter.on('myEvent', function () {
   console.log('Event fired');
});