changed

Negative test cases in random tests are improperly generated: they're [ab]{n} for some random n, which does not perform well as test cases.

Fixed! Thanks

Also this is a duplicate of this and (to a lesser extent) this

The conditions provided do not make sense:

The string will contain only characters from the ranges [a-z] and [1-9].

Why 0 is omitted? 0 is a valid morse code target.

Meanwhile, The first fixed test in the sample tests already contains a whitespace, which is outside the proposed range (and not directly mappable in morse code).

If the string is empty, return null.

This do not make sense either. Empty string can be naturally mapped to empty string. Only null would map naturally to null.

Related, but each character in morse code should be separated by a whitespace. Continuous morse code with no separators is always ambiguous (unless it's a single E/T), so this result format is useless to anyone who'd want to use this function.

fixed! Thanks

https://www.codewars.com/kata/reviews/66585cd68b728d9316783ca4/groups/66585d85c907a07a0516bcce