I dont even know what to return? instructions very unclear

approved :]

Haskell translation

Good kata

Oh, you're right. I thought that was part of your code, because I saw you used a map :p This is actually an issue then.

Edit: node 8 disabled.

if you attempt function checkThreeAndTwo(array) {
return true
} on node v8 it throws you stderr.

There is no ?? operator in code above

Did you select node v18 at the top? If that doesn't fix it, maybe you modified sample tests?

Either way, you should include the actual error message, not just the line that caused the error. If I run your code with node 8, I get "SyntaxError: Unexpected token ?", which makes sense, because ?? didn't exist in earlier versions.

Changed node version to 18 and problem is solved

I have stderr even if function is primitive and return constant value

STDERR:
/home/codewarrior/index.js:42
(map, x) => map.set(x, (map.get(x) ?? 0) +

done

Merged.

as reported below, require set is missing in the Ruby tests suite. fixed here, along with upgrading assertions to RSpec instead of the deprecated Codawars framework

sometimes one wonders what occurs within their own skull...
This is indeed best practice.

I don't think that requirement should exist to begin with. The original kata language is js so it's probably the usual fascination with coercion. If original language was java it would have been a method in a class instead.

It normally shouldn't. I assume that tests are weak, but I also don't understand the need for validating input. xD