Recursion 🤘

Your answer is an array of strings while the expected output should be an array of integers

It's the same thing for every katas: you need to write a function that solves the task, tests call your function and check it does the job correctly. If you are not familiar with how Codewars works, you should have a look at the documentation (Chrono79 gave you the link). However, not a kata suggestion.

Your function is called by the tests, read this: https://docs.codewars.com/getting-started/solving-kata to get how Codewars works.

The input is passed through the argument, and where do you see you should call the function yourself?