This is actually not the best way of solving this problem. The instructions say to consider there being a large number of inputs. In terms of Big O, if you submitted this solution for production code, you'd have a LOT of people mad at you.

Solved in very short way intresting!!

I wouldn't really consider this a best practice, because the variables lose their meaning the second you turn them into chars, but great solution.

spoiler flag, plz...

From Details:
"Note that an empty string, or no arguments, should result in the ouput being ""(empty string)."

No. The []s only mean that. The slashes denote the start and end of the regexp object.

Ah, I see. So do the two "/"s mean to find any of the following characters? Also by character grouping, is it similar to an array? Sorry if I'm being a nuisance again

Looks like someone overtook me in providing an explanation. :-)

Yeah... this is a pretty "clever" solution. Fine, for sure, but leaves a lot of room for confusion as well as unexpected amount of parameters. Still... neat to see this idea.

Hi, so I've done some problems in Ruby, but I have yet to do any in JS. Despite this, when I try to filter out 'Kata that I haven't completed' and look for only problems in JS, it also eliminates the ones that I have already done in Ruby. Fix this please!

HAHAHAHAHHAHAHAAHAHA!