Private functions in ES5

private_functions.js

module.exports = function(){
  var self = {};
  
  //constructor stuff here
  
  var private = 1;
  self.public = 2;
  
  var privateFunction = function(){
    console.log('this is a private function');
  }
  
  var publicFunction = function(){
    console.log('this is a public function');
  }
  
  return self;
}