Some JavaScript Patterns

ClassPattern.js

var Class = function(){
        //private
	var privateVariable = 2;
	
	function privateFunction(){
		return 5;
	}
        //public
	return {		
		publicFunction1 : function(){
			return privateFunction();
		},	
		publicFunction2 : function(){
			return privateVariable;
		}
	};
}

//usage
var myObject = new Class();
myObject.publicFunction1();  //returns 5
myObject.publicFunction2();  //returns 2
myObject.privateFunction();  //throws error
myObject.privateVariable();  //throws error

ImmmediatelyInvokedFunctionExpression.js

//Immediately Invoked Function Express (IIFE)
//function is wrapped in a closure, and then invoked immediately.
(function(){
  // code goes here
})();

SingletonPattern.js

//invoked immediately
var Class = (function(){
        //private
	var privateVariable = 2;
	
	function privateFunction(){
		return 5;
	}
        //public	
	return {		
		publicFunction1 : function(){
			return privateFunction();
		},
		publicFunction2 : function(){
			return privateVariable;
		}
	};
})();

//usage
Class.publicFunction1();  //returns 5
Class.publicFunction2();  //returns 2
Class.privateFunction();  //throws error
Class.privateVariable();	//throws error