Question

I’ve got a module object that I want to clone and then override a function for.

var Module1 = (function () {
 var hello = "hi there!";
  return {
   sayHello : function () {
     console.log(hello);
   }
  }
})();

 var Module2 = (function (old) {
  var my = {}, key;
   for (key in old) {
    if (old.hasOwnProperty(key)) {
      my[key] = old[key];
    }
  }

  my.sayHello = function () {
    console.log(old.hello + " again");
  }

  return my;
}(Module1));

Is there a way to access the ‘private’ variable ‘hello’ from the submodule? Calling Module2.sayHello() (on the code shown above) prints undefined again!.

Answer 1

No, you can’t.

You can add

getHello : function () {
    return hello;
}

into Module1’s return block, in this case you expose a public function which reuturn’s Module1’s private vairable hello.