Javascript's initial code:

function createPhoneNumber(numbers){
  
}

The function is createPhoneNumber and its argument is numbers. If you do something like this:

function createPhoneNumber(numbers){
  return "(123) 456-7890";  // numbers is not used in the function's code
}

It doesn't matter if you call your function like this: createPhoneNumber([1, 1, 1, 1, 1, 1, 1, 1, 1, 1]) the answer will be "(123) 456-7890" instead of "(111) 111-1111". And that's what's wrong with your code.

The question did not provide any required function, parameter or argument names, so I'm not sure what you mean.

There is no issue with the tests, your code isn't using the function's argument, so, no matter which value you call your function with, the answer will be the same.

There seems to be an issue with this test.

Overall, this was good practice. I think the kata should allow for the user to produce their own variable names. When I created my own variables, my solution failed despite the code being correct.

This might be my favorite.