multiple-instance.js

var MultipleInstance = (function() {
	var uid = 0;
	function MultipleInstance() {
		// Increment the ID and make it a read-only property
		Object.defineProperty(this, "id", { __proto__: null, value: ++uid });
	}
	return MultipleInstance;
}());

MultipleInstance.prototype.whatever = function() {
	console.log("Hello, I am instance " + this.id);
}