result-ts

Rust-like Result/Option type implementation for TypeScript.

日本語版のREADMEはこちら

Installation

npm

npm install @cffnpwr/result-ts

or

npx jsr add @cffnpwr/result-ts

yarn

yarn add @cffnpwr/result-ts

or

yarn dlx jsr add @cffnpwr/result-ts

pnpm

pnpm add @cffnpwr/result-ts

or

pnpm dlx jsr add @cffnpwr/result-ts

Bun

bun add @cffnpwr/result-ts

or

bunx jsr add @cffnpwr/result-ts

Deno

deno add npm:@cffnpwr/result-ts

or

deno add jsr:@cffnpwr/result-ts

How to Use

Result type

import { type Result, Ok, Err } from "@cffnpwr/result-ts";

const result1: Result<number, string> = Ok(42);
const result2: Result<number, string> = Err("error");

console.log(result1.isOk()); // true
console.log(result1.isErr()); // false
console.log(result1.unwrap()); // 42

console.log(result2.isOk()); // false
console.log(result2.isErr()); // true
console.log(result2.unwrapErr()); // "error"

// Transform values
const doubled = result1.map((n) => n * 2);
console.log(doubled.unwrap()); // 84

// Chain operations
const parsed: Result<number, string> = Ok("42").andThen((s) => {
  const n = Number(s);
  return Number.isNaN(n) ? Err("not a number") : Ok(n);
});
console.log(parsed.unwrap()); // 42

Option type

import { type Option, Some, None } from "@cffnpwr/result-ts";

const some: Option<number> = Some(42);
const none: Option<number> = None();

console.log(some.isSome()); // true
console.log(some.isNone()); // false
console.log(some.unwrap()); // 42

console.log(none.isSome()); // false
console.log(none.isNone()); // true
console.log(none.unwrapOr(-1)); // -1

// Convert to Result
const result = none.okOr("no value");
console.log(result.isErr()); // true
console.log(result.unwrapErr()); // "no value"

API Reference

See docs/API.md for full API documentation.

License

MIT License