I just solve it and there is sooo much sht with zero which has typeof number but did not work as it shoould. It simply did not return it as a number.
Also got problems with empty strings, because in my solution i have a validation for number. BUT empty strings somehow becomes a NUMBERS and returs back!! So much time spent for this just cos of....
I was really diappointed when the top solution is a (spoiler) method and it did not work for me!!!

it is working.. so much reefs here..

i found the same issue and realized what was the problem... extremely hard to solve it)) as for me not 7ky
but, ty for this kata - forced to learn a bit

Please read the posts below, it's been asked and answered many times already. That string has a trailing space or a new line (hard to know without markdown).

Please read the posts below, it's been asked and answered many times already.

seems 1234 doesn work this way
Wrong output for '1234
': expected true to equal false