Why does it say

amount.indexOf is not a function as an error but works running in Atom?

I'm not sure what his point is with receiving n. The other things with receivng and working with the string and array I understand.

How have this been upvotede 4 times? This is not good.

Thanks! I fixed the missing }

Fixed

Thank you. I managed to solve it by changing my tactic. :) And didn't see the (byte) in the print heh

Enhanced loop will make your code shorter. Still nice :)

Shouldn't "63" be valid since every character appears only once? Why does the test say it should be false?

I also get this. How do I fix it?

This is overkill