They’re also pretty bad at typescript generics. They’re quite good at explaining concepts (like mapped types), but when push comes to shove they generate all sorts of stuff that looks convincing, but doesn’t pass the type checker.

And then you’ll paste in the error, and they’ll just say “ok I see the problem” and output the exact same broken code lol.

I’m guessing the problem is lack of training data. Most TS codebases are mostly just JS with a few types and zod schemas. All of the neat generic stuff happens in libraries or a few utilities