This comment saved me! I was struggling to get why on the random tests even my first instruction was wrong... that's the answer, you don't always start on top floor.

Indeed a basic test like that would help saving some frustration :)

I like this kata a lot-- learned a lot about how numbers/coercion works in javascript by reading the other answers.
Will say it felt a tad easy for kyu 5 though.

Imo, there should be a case in the basic tests where the starting floor isn't the top, or at least that it should call a bit more attention to it in the instructions.
I could be wrong, but it seems like an unintended "gotcha" for this problem when it's not clear that that's the case causing your code to fail.

You're doing recursion wrong, that's why your code fails. You need to return the recursive call to your function.

This seemed a bit harder than the other 6 kyu problems out there.

Some of that is because of the noted unclear instructions ("rotate it left" is not a clear shorthand for "move the first character to the last position in the string".

But also this was just harder to do, even once instructions were understood (imo of course).