Thanks! I appreciate the compliment.

One line of comprehensable code - great job!

"For this challenge, create a function that adds my guy at the end of every sentence."

Your code added this phrase only at the end of text my guy.
;)

Dead link in description: https://preview.codewars.com/kata/beat-the-bookmaker

Everybody/most of us usually use(s) console.log after receiving error message to check created code, and in this kata is not possible. Why?

You're right, when your code is not ok, the log doesn't show.

Code like this did not print the output from console.log()

some code [...]
console.log(result)
return result

I received only messages from test like: "Passwords use a limited characterset!".

What do you mean you can't use it?

Solved, but I'm curious why I can't use console.log() in JS?

Author is gone. I add both informations in the description.

Array with letters it's only example, but don't bother with letters. Probably you missed this line: "If the callback function returns true then the loop will stop and no additional values will be iterated." The rest will be (or was) easy for you, after all you have 1 kyu :)

Oh, it works :) I thought that transforming long string into array and operation on array will be too memory consuming and I did operation directly on string, but in almost the same way: while loop + removing last char from 'a' and 'b'. Although my solution is longer...

Author is gone. According to docs: https://docs.codewars.com/concepts/kata/translations/ please label your comment as Suggestion.