>Running the typechecker independently of the bundler is really common in TypeScript
maybe it is common, I can't speak to that but in my opinion a large part of the success of webpack was probably because they bundled the typechecking. Because that's the only workflow that makes sense, imagine a c# compiler that quickly outputs executable IL code but half the time it's broken because it didn't do any type checking and you have to wait for the IDE based type checker anyway. On every build. It just doesn't make sense to work this way, you never want a fast, silently broken build which is what you get with non-typechecked fast builds.
maybe it is common, I can't speak to that but in my opinion a large part of the success of webpack was probably because they bundled the typechecking. Because that's the only workflow that makes sense, imagine a c# compiler that quickly outputs executable IL code but half the time it's broken because it didn't do any type checking and you have to wait for the IDE based type checker anyway. On every build. It just doesn't make sense to work this way, you never want a fast, silently broken build which is what you get with non-typechecked fast builds.