This might shed some light

If it doesn't pass the tests, it doesn't return the right answer. No way it can be different: that's what tests do: compare your output with the expected one and display the corresponding message if they don't match.

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The code you provide is incorrect, it throws a SyntaxError.

I strongly advice you to read carefully this: https://docs.codewars.com/training/troubleshooting/

You don't test the right input.

There is an error in one of the random tests for JavaScript.

It reads:
expected '0:00:01' to equal '00:00:01'"
even though my output is definitely
'00:00:01'

Here's the console.log for my two cases:

console.log(getMilitaryTime('3:45:05PM'))
console.log(getMilitaryTime('12:00:01PM'))

3:45:05
00:00:01

Remove those calls to your function at the end of your code, that's what's being detected as recursion, not set or repeat.

I am not understanding why using Set and .repeat are both considered using recursion. If I don't understand what makes these recursive, I won't be able to find a method of solving this kata

The index should be in the range [0..length-1]. If it is not, GetNth() should throw/raise an exception

Thank you for asking this great question!

And thank y'all for the responses!

Your code is filtering the mutated list instead of the original one, that's why you get the wrong order.

Node 14 should be enabled and chai should be used for assertions.