[alangpierce]

I've been adding TypeScript types to a bunch of JavaScript code recently, and it really is much safer and faster than trying to move to a different language. As long as you are only adding types, you don't have any chance of introducing a bug, since the types just compile away, and plenty of real-world code (especially untyped code) tends to have subtle details that you might overlook if you're reading it for the first time.

Another thing to keep in mind is that type annotations can be done incrementally. You can't take 1000 Python files and port them to Go one by one, but you can add types a little bit at a time with a completely usable codebase at every intermediate step.