Template of an Object Oriented node.js module

gistfile1.js

var Class = (function Class() {
	var singleton_private_variable = 'Singleton Private variable';

	function singleton_private_function () {
		return 'Private Function';
	}

	var Obj = {

		singleton_public_variable: 'Singleton Public variable',

		singleton_public_function: function() {
			return 'This is Singleton Public method. it can access ' + singleton_private_variable + 's, '
			 + this.singleton_public_variable + 's and ' + this.public_variable + 's.';
		}

	};

	(function(){

		console.log('Singleton Constructor');

	})();

	return Obj;

})();

module.exports = function() {
	return Object.create(Class, (function(){
		var private_variable = 'Private variable';

		(function(){
			console.log('Constructor');
		})();
		
		return {

			public_variable:  {
				writable: true,
				configurable: false,
				enumerable: true,
				value: "Public variable"
			},

			public_function:  {
				writable: false,
				configurable: false,
				enumerable: true,
				value: function(){
					return 'This is Public method. it can access ' + private_variable + 's, '
			 + this.singleton_public_variable + 's and ' + this.public_variable + 's.';
				}
			}

		};

	})());
};