gistfile1.js

	var observable = function (data) {
		var _data = data;
		var _callbacks = [];
		var self = this;

		this.subscribe = function (callback) {
			_callbacks.push(callback);
		};

		this.get = function () {
			return _data;
		};

		this.set = function (newValue) {
			_data = newValue;
			for (var i = 0; i < _callbacks.length; i++) {
				_callbacks[i](newValue);
			};
		};

		this.watch = function (callback) {
			_callbacks.push(callback);
		};
		return self;
	};