DST means STD in brazilian portuguese so I jumped when I saw the title lmao

This has been cleaned up. thank you for this suggestion

Random tests have now been added

Fair point, will update shortly

This is clever, but not best practise. Just use latest libraries for assertions in the test cases.

const Test = {
  describe, 
  it, 
  assertEquals: assert.equal, 
  assertDeepEquals: assert.deepEqual 
};

There are no sample tests or random tests.

This Kata should not be 7 Kyu. Even though it is not necessary to utilize tail call optimization to complete this Kata, that is the method for making the code more efficient mentioned in the description. Tail code optimization is not a beginner topic. If you are new to programming, feel free to challenge yourself by reading up on tail call optimization, but don't be discouraged if you have difficulty understanding the topic or solving this Kata. There are plenty of 7 Kyu Kata which are appropriate for beginners, so feel free to try those and come back to this Kata when you have a more solid programming foundation.

Please use the spoiler flag when posting potential spoilers and use appropriate formatting when posting code. See: https://docs.codewars.com/training/troubleshooting#post-discourse

[...] in my opinion my code is correct and definitely works on vscode

Your code doesn't do what the kata asks at all, so I'm not sure what you mean by "correct".

You need to be able to handle any function, not just the 4 you hardcoded. The functions are also passed in as functions, not as strings.

Rust description has a typo: x + 30 instead of x * 30

New Rust translation ready for review.

Missing fixed and sample tests in JS of empty array, which could invalidate this solution

fixed