Did you try running the build script and working directly in “out/“? I doubt it would have been easier. Big projects simply take time to learn and contribute to, TypeScript or not.

Actually, I’d say VS Code would be much harder to contribute to without TS. You mentioned adding a setting. This requires touching several different methods (parsing, cleansing, etc.). With TypeScript, the compiler instantly tells you when you have forgotten to implement a part of the setting pipeline. With JS, the runtime gives you some “undefined is not a blah” error to track down.

Type annotations strongest advantage is when diving into a new code base you've never read before. Can't see how it can make it harder to track down bugs. It does prevent monkeypatching so some "i'll just add a quick fix here" are going to be harder, and that is a good thing, otherwise you end up with spaghetti soup.

> Using Typescript makes this a lot harder.

Does it? I think type annotations makes it easier. It means you don't need to think less hard, which makes unknown code, which is always harder to read, a bit easier to read.