gistfile1.txt

var CLASSNAME = (function(self){
   var _private = 0;
   
   function __init(){
      //run self init stuff here
   }

   function returnPrivate(){
      return _private;
   }
   
   function fnAdd(num){
    _private+= num;
    return returnPrivate();
   }

   function fnSubstract(num){
    _private-= num;
    return returnPrivate();

   }

   __init();

   return {
      fnAdd : fnAdd,
      fnSubstract : fnSubstract
   }
})(CLASSNAME || {});

//ForExample call CLASSNAME.fnAdd(2).  Keep calling it and you will see the private keep changing

Module revealing pattern, with Augmentation