what boundaries do you think Elm is pushing as a language?
It is a cool language and platform, but to me it looks like with time it has actually become more conservative.
TS on the other hand appears to contain some interesting new things on each release (possibly too many). Case in point, Lookup and Mapped types in 2.1 seem like a brilliant idea.
TypeScript is a highly practical and pragmatic language. Use it for anything serious.