Have you seen "The modern way to write TypeScript"? https://github.com/DanielXMoore/Civet

*runs for cover*

omg. ok, adopting some F features is an interesting idea. but why are they trying to make that thing with syntax happen?

hehe, I guess they loved CoffeeScript and/or minimalism. But if I want F# features I'd rather use F# and compile to JS with Fable, or simply use ReScript which is more sound than TypeScript any way. If I should learn a new syntax, why not get a better type engine in the process?

Arguably coffeescript was a big push to move JS spec forward into ES6 and beyond.