You're right. I corrected this mistake and all JS tests passed. Thank you for your help.

You're using the built-in function in line 2 incorrectly.

no issue here. The const modifier tells you that you should not mutate the array. You can decide to write bad code and do it anyways, it's not the tests suite's concern

Thank you for your answer. I guess there is something wrong with my JS solution then.

Both seem fine to me. I just passed on both with very similar solutions.

I was expecting the supplied data not to be mutable. But as I wrote I'm not sure how it was intended.

I am not sure I understand the issue, and when I am trying to sort the input array I get an expected warning:

solution.c:13:9: warning: passing 'const unsigned int *' to parameter of type 'void *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
  qsort(gifts, length, sizeof(unsigned), cmpfun);

What would be the behavior expected by you? Do you mean that it should be generally not allowed to mutate inputs in this kata?

For the C version.

The function is defined as

  size_t how_many_gifts(unsigned max_budget, size_t length, const unsigned gifts[length])

However, the data pointed to by gifts is still mutable, i.e you don't need to make a copy in order to sort.

Marked as issue as I'm not sure what was intended.

approved by someone

C Translation

This kata is a subject to deduplication process here: https://github.com/codewars/content-issues/issues/151.
Please join the discussion to help us identify duplicate kata and retire them.

approved

Really sorry, I marked the issue resolved when I wanted to put the spoiler flag on my comment... Feel free to reraise an issue if you feel like.