[SOLVED] Prototype a function to another function JavaScript?

Prototype a function to another function JavaScript?

I was asked the following question at an OA. I did not figure it out and I would like to know the solution to this question.

I was asked to console Thank you for Logging in Dan:

var Wrap = (function(){
  function User(name){
    this.name = name;
  }
  var d = function(){
    console.log('1');
    return "Thank you for Logging in" + this.name;
  };
  User.prototype.thankForLoggingln = d;
  return User;
})();

I figured that out that Wrap returns User, which make Wrap equals to User. And if I do Wrap('Dan'), this.name will change to Dan.

The question is, I cannot access to thankForLoggingln. I have tried Wrap.()thankForLoggingln() and things like this, I got reference errors. Any idea?

Solution

Your understanding of

I figured that out that Wrap returns User, which make Wrap equals to User

is correct. But when you say Wrap('Dan'), in this case this would refer to the Global object. In case, you are running this on a browser, then you can access your name variable by window.name. You must call the function with the new keyword, so that a new object would be created and this would refer to the newly created object and User would be it's constructor. In this case it would have access to the thankForLoggingln function.

So the correct way of doing it would be

var user = new Wrap('Dan');
user.thankForLoggingln();

For more information read constructor and You Don't Know JS