If you don't write Web stuff, you can ignore JS completely, and PureScript too.
If you prefer dynamically-typed languages, use them directly (JS, CoffeeScript, etc.)
If you prefer statically-typed languages, you must care about a dynamically-typed language, since every statically-typed language can be thought of as a dynamically-typed language + a machine-checkable safety net. For example, Haskell/ML/etc. are built on Lambda Calculus, C/FORTRAN/etc. are built on machine code. If you're programming for the Web, why not use JS as the dynamic part of your language (the "computational content")?
I didn't want my comment to devolve into an argument about the merits of static vs. dynamic. My comment is really to ask why would I use Typescript for web programming? Where does it fit? It doesn't seem to fit in or fill a need that isn't already possible with any combination of static and dynamic languages used separately. In fact I feel it blurs the separation of concerns between static vs. dynamic.
If you prefer dynamically-typed languages, use them directly (JS, CoffeeScript, etc.)
If you prefer statically-typed languages, you must care about a dynamically-typed language, since every statically-typed language can be thought of as a dynamically-typed language + a machine-checkable safety net. For example, Haskell/ML/etc. are built on Lambda Calculus, C/FORTRAN/etc. are built on machine code. If you're programming for the Web, why not use JS as the dynamic part of your language (the "computational content")?