module.js

/* global console: true */
var module = (function () {
  function privateFn () {
    console.log('I am a private function!');
    return 8;
  }

  var privateVar;

  return {
    method1: function () {
      return privateFn();
    }
    ,getPrivateNumber: function () {
      return privateVar;
    }
    ,setPrivateNumber: function (value) {
      if (typeof value !== 'number') {
        return;
      }

      return privateVar = value;
    }
  };
} ());

console.log(module.method1());
console.log(module.setPrivateNumber(5));
console.log(module.getPrivateNumber());