Typed functional programming in TypeScript

fp-ts provides developers with popular patterns and reliable abstractions from typed functional languages in TypeScript.

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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

The stable version is tested against TypeScript 3.3.3, but should run with TypeScript 2.8.0+ too.

• Strictness – This library is conceived, tested and is supposed to be consumed by TypeScript with the strict flag turned on.
• Compatibility – If you are running < typescript@3.0.1 you have to polyfill the unknown type. You can use unknown-ts as a polyfill.