[wwwigham]

The TS team implemented the TS parsing support in Babel. You are correct that the TS compiler is still needed for the typechecker, however.

[jasonkillian]

Ah, I didn't realize this, very cool collaboration! For those who are reading this and might find it helpful, here's a link to the official blog post on the work: https://blogs.msdn.microsoft.com/typescript/2018/08/27/types...