Singleton.js

/**
 * Example Singleton constructor.
 * I wish this was extendable but you gotta copy/paste the 2 lines into any object you want to be a Singleton
 *
 * @returns {*}
 * @constructor
 */
function Singleton () {
    if ( arguments.callee._singletonInstance ) return arguments.callee._singletonInstance;
    arguments.callee._singletonInstance = this;
}

z.example.js

var Thing1 = new Singleton();
var Thing2 = new Singleton();

Thing1.foo = 'bar';
Thing2.foo; // 'bar'