Result<T, E> for TypeScript

A small Result<T, E> implementation for TypeScript, inspired by Rust's Result.
It provides a typed way to handle success and error without throwing, while still giving you escape hatches like unwrap and expect when needed. Just don't use unwrap in production code!

Features

• Ok<T> and Err<E> constructors
• Discriminated Result<T, E> type
• Type guards: isOk(), isErr()
• Helpers: isOkAnd, isErrAnd, expect, unwrap, match
• No external dependencies

Basic Usage

import { Result, Ok, Err } from "./result";

function parseIntResult(s: string): Result<number, string> {
  const n = Number.parseInt(s, 10);
  return Number.isNaN(n) ? Err(`'${s}' is not a number`) : Ok(n);
}

const r = parseIntResult("42");

if (r.isOk()) {
  console.log("value:", r.value);
} else {
  console.log("error:", r.error);
}

Using match for exhaustive handling:

const msg = parseIntResult("100").match({
  ok: v => `valid: ${v}`,
  err: e => `invalid: ${e}`,
});

Using expect and unwrap (not recommended for production):

const x = parseIntResult("10").expect("expected an int");
const y = parseIntResult("oops").unwrap();

Using isOkAnd and isErrAnd:

parseIntResult("7").isOkAnd(v => console.log("got:", v));
parseIntResult("abc").isErrAnd(e => console.log("problem:", e));