Codility:
1. Using fetch or axios.
2. Readable/Transform Streams in Nodejs, something about converting each character of a word to caps on transform only if they're alphabets.
3. Proxy Objects in JavaScript, using it to intercept get and sets so you can validate type based on key name, eg "age_int":6, valid, but, "username_str":9, not valid.
Some test cases won't pass no matter what because they are not in how the function is described to work, so you have to manually check why each one is failing. Didn't pass all tests, but still got interviewed for the next round.
HR:
They're not honest in my opinion, they come off as trying to be but you'll find out yourself when you do the interviewing process, feedback they'll give you if you get rejected won't make any sense either, because they literally confirmed what I bought up wasn't a problem anymore, but rejected me in the end because of the exact same thing, due to supply - demand dynamics.
Conclusion:
If you're really job searching, you have no job, it's okay to give it a try to flex your interviewing muscles, if you already have a job and job searching, probably don't waste your time.