Reraised above, due to lack of random tests

That was helpful. Thank you

surprising!

0. It's faster to compare (IMHO) than '==';
1. It's more consistent and obvious;
2. It's recommended by JSLint, for example.

My solution is similar to yours. But I prefer to not hardcode a lot of [-4..-1]. Better to create helper method, because if requirements changes - you should edit only one helper method instead of looking through all the source codes.

also #_ =P

Nevertheless, I just learned a new enum =D.

Well, description limits n to 0 <= n < 1000000000. I think gsub(/.../, '\0,') would be shorter and faster than scanning for variable length.

@JoshBrodieNZ You're right! That's a great update to CodeWars. It has been very frustrating being unable to edit this kata!

Have you tried to edit the description? My understanding is that recent changes should allow the description on a locked kata to be edited.

This kata is way too old for me to edit it now (it's locked), but if I could I would change the description to:

"Write a function named numbers that returns true if all the parameters it is passed are of the Number type".

So new Number(4) is an Object. The other one that tripped some people up is NaN, which is of course a Number.

nice