bye-exceptions

Tiny Result pattern for explicit, type-safe error handling in TypeScript.

Instead of throwing, wrap operations in attempt and handle { error, value } results.

Install

npm install bye-exceptions

Usage

Sync

import { attempt } from "bye-exceptions";

const result = attempt(() => JSON.parse('{"ok": true}'));

if (result.error) {
  console.error(result.error.cause);
} else {
  console.log(result.value);
}

Async

const result = await attempt(async () => {
  const res = await fetch("/api/user");
  return res.json();
});

if (result.error) {
  // handle failure
} else {
  // result.value is typed
}

Promise

const result = await attempt(fetch("/api/user").then((r) => r.json()));

Writing a result function

import { ok, err, type Result } from "bye-exceptions";

function divide(a: number, b: number): Result<number, "division_by_zero"> {
  if (b === 0) return err("division_by_zero");
  return ok(a / b);
}

const result = divide(10, 2);

if (result.error) {
  console.error(result.error); // "division_by_zero"
} else {
  console.log(result.value); // 5
}

API

| Export | Description | | ------------------------ | ---------------------------------------------------------------------- | | attempt(fn \| promise) | Runs sync/async code or a promise; returns Result or ResultPromise | | ok(value) | Creates a success result | | err(error) | Creates a failure result |

Types

• Result<T, E> — { error: null, value: T } or { error: E, value: null }
• Exception<E> — { cause: E } (error shape from attempt)
• Ok<T>, Err<E>, ResultPromise<T, E>

License

MIT