TypeScript is not JavaScript with type annotations. One of the modes, may be. TypeScript supports emitting old JS constructions which look nothing like original typescript code. So it's more like type annotations + babel. Adding one more thing to this set. Extremely useful thing. I think it's a good idea. I miss it. It's crazy that I can't JSON.parse string into typed structure safely. Every other language can do that.
You can easily parse json into types using something like typebox. Not only does this work, it works much better than many other languages. Have fun trying to represent even a simple patch request, or discriminated union, in something like c#
