observer pattern for js

observer_pattern.js

var Observable = function () {
  this.observers = [];
};

Observable.prototype.register = function ($) {
  if (this.observers.indexOf($) == -1) {
    this.observers.push($);
  }
};

Observable.prototype.unregister = function ($) {
  var index = this.observers.indexOf($);
  if (index != -1) {
    this.observers.splice(index, 1);
  }
};

Observable.prototype.unregister_all = function () {
  this.observers.splice(0, this.observers.length);
};

Observable.prototype.catch = function () {
  for (var i in this.observers) {
    this.observers[i].emit.apply(this, arguments);
  }
};

var Observer = function () {
};

Observer.prototype.emit = function () {
};

var Obzy = function () {
  Observer.apply(this, arguments);
};
Obzy.prototype = Object.create(Observer.prototype);
Obzy.prototype.constructor = Obzy;

Obzy.prototype.emit = function () {
  console.log("hi", this.name);
};

var Human = function (name) {
  Observable.apply(this, arguments);
  this.name = name;
};

Human.prototype = Object.create(Observable.prototype);
Human.prototype.constructor = Human;

var eray = new Human("Eray");
var new_obzy = new Obzy();
eray.register(new_obzy);
eray.catch();