GeezerVison

Answer: an error.

Try it:

function makeUser() {
  return {
    name: "John",
    ref: this
  };
}

let user = makeUser();

alert( user.ref.name ); // Error: Cannot read property 'name' of undefined

That’s because rules that set this do not look at object definition. Only the moment of call matters.

Here the value of this inside makeUser() is undefined, because it is called as a function, not as a method with “dot” syntax.

The value of this is one for the whole function, code blocks and object literals do not affect it.

So ref: this actually takes current this of the function.

We can rewrite the function and return the same this with undefined value:

function makeUser(){
  return this; // this time there's no object literal
}

alert( makeUser().name ); // Error: Cannot read property 'name' of undefined

As you can see the result of alert( makeUser().name ) is the same as the result of alert( user.ref.name ) from the previous example.

Here’s the opposite case:

function makeUser() {
  return {
    name: "John",
    ref() {
      return this;
    }
  };
}

let user = makeUser();

alert( user.ref().name ); // John

Now it works, because user.ref() is a method. And the value of this is set to the object before dot ..