Why would anyway want to clot up vanilla javascript (increasing its compiling load with a bunch of superfluous crap from TS?) But if it has to be - to help those who got tricked into using TS and became dependent - it should be an opt-in 'feature' only. With an entirely detached compiler. And those who need it can maintain it.

Or, better still, someone could just write a book on how to wean yourself away from TS.