rusty-ts

Rust-inspired Option and Result types for TypeScript.

Usage

npm install --save rusty-ts

Option

import { Option, option } from "rusty-ts";

const a = option.some("foo");
const b = a.map(x => x.toUpperCase());

const c = option.some(3);
const d = a.andThen(a => c.map(c => a.repeat(c)));

function f(opt: Option<string>) {
  console.log(opt.unwrap());
}

// Logs "FOOFOOFOO"
f(d);

Result

import { Result, result } from "rusty-ts";

const a = result.ok("foo");
const b = a.map(x => x.toUpperCase());

const c = result.err(3);
const d = c.orElse(cError => b.map(bVal => bVal.repeat(cError)));

function f(opt: Result<string>) {
  console.log(opt.unwrap());
}

// Logs "FOOFOOFOO"
f(d);

Why `Option` and `option` (or `Result` and `result`)?

Option is just an interface—any Option-compatible code you write will be compatible with any implementation of Option. This gives you the flexibility to implement Option however you like.

However, you probably don't want to write your own implementation, so we provide you with one out-of-the-box. The option object provides a namespace that groups the factories of the default implementation. To instantiate an Some or None variant, simply call option.some() or option.none(), respectively.

The same goes for Result (the interface), and result (the namespace containing the factory functions).

API Docs