Typescript's type system actually pretty limited. I spent about two weeks trying to do something nice with it before giving up and trying Scala.js, where I was able to do everything I wanted within a couple of days.
Typescript gets better all the time, I didn't the last year or so run into anything I couldn't do in Typescript (although using it all the time, and Scala too)
I think it was last year. There was no nominal typing at all, the unsound variance of arrays meant I couldn't really trust my types anyway, I wasn't able to treat structures generically as records the way I'd like (i.e. no shapeless equivalent) and of course there was no HKT.
Ok. I probably don't use so very advanced parts of the type systems (didn't know about Scala Shapeless until now) so I might not notice the differences.
