Finally things are heading in the right direction. Can't wait for more to do this. Typescript might be good for some, but I'm glad to see the hype finally begin to fade, so the rest of up can breathe again.
The biggest hurdle to using TypeScript is the build step before it can actually be run. If the type annotation TC39 [0] comes to pass this would be largely taken care of; _hype_ waxes. (unfortunately the proposal has been stagnant for more than a year now)
A lot of the new frontend codebases involve a build step before running. For such codebases, TypeScript's build hurdle has already been overcome.