I think it’s just as well he was opinionated and realized it wasn’t going to work. Ironically, if this was actually the start of the job, I think bailing might have made more sense. Given that it was just a one week work trial, I feel like there’s little downside in just toughing out the remaining couple days and then deciding. Personally, if I found out the Typescript thing was a secret test of adaptability (which seems extremely unlikely) I would move on, I wouldn’t want a place that plays those kind of games.