I mean, yes, exactly?? That's TypeScript's entire reason for being, and it's no small thing.

I use TypeScript where I would have used plain JavaScript. If I have a reasonable choice of an entirely different language - ie, I'm not targeting browsers or Node - then I would definitely consider that.

I personally haven't seen that any compile-to-JS language is worth the interop tax with browsers or the JS ecosystem, and I've built very complex apps on GWT and used to be on the Dart team working on JS interop.