[pr0crastin8]

As someone quite in love with functional programming (background in Haskell and Scala), one thing that seems quite obviously missing here and in my Javascript experience so far is the use of typeclasses as a form of ad-hoc polymorphism.

Is there a nice (i.e. not too much boilerplate) way of using them in the land of Javascript/Typescript?

[chrischen]

See https://github.com/gcanti/fp-ts. Heavily haskell-inspired and includes a TS implementation of higher-kinded types.

[samhh]

This is definitely the best option in the TS ecosystem but it's not meaningfully implementing typeclasses from the perspective of the end user. There's no single `fmap` for example, instead you'll be using dedicated `Array.map`, `Option.map`, etc.

[shirogane86x]

As far as i remember there's functions that take explicit typeclass dictionaries (that you can compose via contramap). So I guess they sort of do typeclasses, but without implicits, which is pretty painful IME. Example: https://gcanti.github.io/fp-ts/modules/Functor.ts.html#map