because it's written "Do not use built in functions." in the description, refering to library base64 functions. but this is not enforced. in python nothing is disabled; in JS it's strange, browser base64 functions are disabled, but since Codewars runs JS in Node, not in a browser, this is useless. i think the best thing to do at this point is to drop that requirement, even if the kata in its current state is very overanked :/

Why do you say that?

any hin where is the problem?

TSError: ⨯ Unable to compile TypeScript
spec.ts (8,31): Property 'G964' does not exist on type 'typeof "/home/codewarrior/solution"'. (2339)
at getOutput (/runner/node_modules/ts-node/src/index.ts:307:15)

Just give me a hint. Is there any special mathematical-type solution?

just to make it clear, .toString(), .padStart() and co. are built in functions, not permitted in this kata, right?