kotaroito/jsbin.nuhag.html

## jsbin.nuhag.html
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JS Bin</title>
</head>
<body>
  <div>
    <button id="myBtn">click</button>
  </div>
</body>
</html>

## jsbin.nuhag.js
var Subject = (function(){
  var pool = {};
  return function(name) {
    if (!pool[name]) {
      var subject = Object.create(Subject.prototype);
      subject.name      = name;
      subject.observers = [];
      pool[name] = subject;
    }
    return pool[name];
  };
})();

Subject.prototype = {
  addObserver: function(observer) {
    this.observers.push(observer);
  },
  removeObserver: function(observer) {
    var index = this.observers.indexOf(observer);
    if (index > -1)
      this.observers.splice(index, 1);
  },
  notify: function(context) {
    for (var i = 0; i < this.observers.length; i++)  {
      this.observers[i].update(context);
    }
  },
};

var Observer = function() {
  return Object.create(Observer.prototype);
};
Observer.prototype.update = function(){
};

Observer.Count = function(name) {
  var o = Object.create(Observer.Count.prototype);
  o.cnt  = 0;
  return o;
};
Observer.Count.prototype.update = function(context) {
  console.log(++this.cnt);
};


(function() {
  var subject = Subject("test");
  subject.addObserver(Observer("o1"));
  subject.addObserver(Observer.Count("o2"));

  var btn = document.getElementById('myBtn');
  btn.addEventListener("click", function() {
    subject.notify();
  }, false);

})();
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<title>JS Bin</title>
	</head>
	<body>
	<div>
	<button id="myBtn">click</button>
	</div>
	</body>
	</html>
	var Subject = (function(){
	var pool = {};
	return function(name) {
	if (!pool[name]) {
	var subject = Object.create(Subject.prototype);
	subject.name = name;
	subject.observers = [];
	pool[name] = subject;
	}
	return pool[name];
	};
	})();

	Subject.prototype = {
	addObserver: function(observer) {
	this.observers.push(observer);
	},
	removeObserver: function(observer) {
	var index = this.observers.indexOf(observer);
	if (index > -1)
	this.observers.splice(index, 1);
	},
	notify: function(context) {
	for (var i = 0; i < this.observers.length; i++) {
	this.observers[i].update(context);
	}
	},
	};

	var Observer = function() {
	return Object.create(Observer.prototype);
	};
	Observer.prototype.update = function(){
	};

	Observer.Count = function(name) {
	var o = Object.create(Observer.Count.prototype);
	o.cnt = 0;
	return o;
	};
	Observer.Count.prototype.update = function(context) {
	console.log(++this.cnt);
	};


	(function() {
	var subject = Subject("test");
	subject.addObserver(Observer("o1"));
	subject.addObserver(Observer.Count("o2"));

	var btn = document.getElementById('myBtn');
	btn.addEventListener("click", function() {
	subject.notify();
	}, false);

	})();