Functional programming in TypeScript

# Introduction `fp-ts` is a library for _typed functional programming_ in TypeScript. `fp-ts` aims to allow developers to use _popular patterns and abstractions_ that are available in most functional languages. For this, it includes the most popular data types, type classes and abstractions such as [Option](https://gcanti.github.io/fp-ts/modules/Option.ts), [Either](https://gcanti.github.io/fp-ts/modules/Either.ts), [IO](https://gcanti.github.io/fp-ts/modules/IO.ts), [Task](https://gcanti.github.io/fp-ts/modules/Task.ts), [Functor](https://gcanti.github.io/fp-ts/modules/Functor.ts), [Applicative](https://gcanti.github.io/fp-ts/modules/Applicative.ts), [Monad](https://gcanti.github.io/fp-ts/modules/Monad.ts) to empower users to write pure FP apps and libraries built atop higher order abstractions. A distinctive feature of `fp-ts` with respect to other functional libraries is its implementation of [Higher Kinded Types](), which TypeScript doesn't support natively. **Inspired by** - [Haskell](https://www.haskell.org) - [PureScript](https://www.purescript.org) - [Scala](https://www.scala-lang.org) # Sponsors

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# Installation To install the stable version: ``` npm install fp-ts ``` Make sure to always have a single version of `fp-ts` installed in your project. Multiple versions are known to cause `tsc` to hang during compilation. You can check the versions currently installed using `npm ls fp-ts` (make sure there's a single version and all the others are marked as `deduped`). ## TypeScript compatibility **Strictness** – This library is conceived, tested and is supposed to be consumed by TypeScript with the `strict` flag turned on. | `fp-ts` version | required `typescript` version | | --------------- | ----------------------------- | | 2.0.x+ | 3.5+ | | 1.15.x+ | 3.1+ | | <= 1.14.4 | 2.8+ (\*) | (\*) If you are running `< typescript@3.0.1` you have to polyfill the `unknown` type. You can use [unknown-ts](https://github.com/gcanti/unknown-ts) as a polyfill. # Documentation **Disclaimer**. Teaching functional programming is out of scope of this project, so the documentation assumes you already know what FP is. - [Docs](https://gcanti.github.io/fp-ts) - [Learning Resources](https://gcanti.github.io/fp-ts/learning-resources/) - [Ecosystem](https://gcanti.github.io/fp-ts/ecosystem/) - API Reference - [version 2.x (current)](https://gcanti.github.io/fp-ts/modules/) - [version 1.x](https://github.com/gcanti/fp-ts/tree/1.x/docs/modules/) # Help If you need help with `fp-ts` check out: - this [Discord server](https://discord.gg/HVWmBBXM8A) - the `#fp-ts` channel on [FP slack](https://fpslack.com/). # Development - [Code conventions](https://gcanti.github.io/fp-ts/guides/code-conventions) # License The MIT License (MIT)

	Stars	Issues	Version	Updated	Created
fp-ts	10,447	188	2.16.5	24 days ago	7 years ago
immer	26,903	36	10.0.4	a month ago	8 years ago
lodash	58,846	69	4.17.21	3 years ago	12 years ago
rambda			9.2.0	17 days ago	7 years ago
underscore	27,230	52	1.13.6	2 years ago	13 years ago

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