fp-ts [1] contains an implementation of Higher Kinded Types, which TypeScript doesn’t support natively (the idea for emulating higher kinded types in TypeScript is based on "Lightweight higher-kinded polymorphism" [2])

[1] https://github.com/gcanti/fp-ts [2] https://www.cl.cam.ac.uk/~jdy22/papers/lightweight-higher-ki...

for a functional library that plays nicely with TS check this out: https://github.com/gcanti/fp-ts

Looks interesting, but I get the feeling I need to have already downed a few gallons of Haskell kool-aid to understand this? Is there a beginner-friendly overview somewhere?

What's nice about Ramda is that while it uses the Haskell-ish vocabulary and type signatures in its docs, someone can also just dive in and start using it as if it were an underscore-like library and not worry about all the more cerebral stuff.

For my fellow italians, I wrote a free "Introduction to functional programming" PDF, check out https://github.com/gcanti/functional-programming

Is there an English translation?

Here's a (partial) porting to TypeScript https://github.com/gcanti/money-ts

working on a fp library for TypeScript if you want to take a look https://github.com/gcanti/fp-ts

You could write the runtime definition and extract the static types from that https://github.com/gcanti/io-ts

thanks for the link - i've never seen that before :)

This is a TypeScript compatible runtime type system for IO validation https://github.com/gcanti/io-ts

what's the state of the JavaScript backend? I do frontend and I'd really love to write some code in idris

Take a look at PureScript [1], it's Haskell-like but strict.

[1]: http://www.purescript.org/

Not sure about TypeScript but with Flow you can get HKT through some contortions https://github.com/gcanti/flow-static-land (in Elm too)

I wrote a library [1] and a babel plugin [2] (bonus point: is Flow compatible) in order to deal with those cumbersome runtime type checks.

[1] https://github.com/gcanti/tcomb [2] https://github.com/gcanti/babel-plugin-tcomb

Heh, me too: https://github.com/philbooth/check-types.js