It's a limit on recursion, not a kata bug.

I concur, you can brute-force it (although I don't know if there would be a more efficient way to just skip numbers, except just checking if they were even or something, but that's all I can really think of) by checking every number, as long as you know how to check if a number is prime efficiently.

Not really a hard Kata.

Is it? I don't think it's that hard as a 6kyu. You just need to think of how many number to test a bit carefully.

Katas like this would be the ones that truly should be up-ranked to 6kyu.

The full example is

// Basic test
let arr = [1, 2, 34, 4, 5, 5, 5, 65, 6, 65, 5454, 4];
waveSort(arr);
Test.assertEquals(isWaveSorted(arr), true);

If you change isWaveSorted to waveSort, you change the test.

Thanks for your feedback. ;-)

Thanks for your suggestion ;-)
This kata was locked by CW. because there are more than 500 guys solved it.