attempt

A minimal, type-safe utility for defensive error handling in both synchronous and asynchronous JavaScript/TypeScript code. Inspired by Go's error handling, attempt and attemptAsync help you avoid unhandled exceptions and keep your code predictable.

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Features

• Tuple-based error handling: No more try/catch blocks scattered everywhere.
• TypeScript-first: Fully typed for safer code and better IDE experience.
• Universal module support: Works seamlessly with both CommonJS and ESM.
• Works with any function: Supports both sync and async, including native Promises.
• Zero dependencies

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Installation

npm install @piyawasin/attempt

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API

attempt(fn, ...args)

Safely executes a synchronous function.

• Returns: [result, error] — If the function throws, result is null and error is set.

attemptAsync(fnOrPromise, ...args)

Safely executes an async function or resolves a Promise directly.

• Returns: Promise<[result, error]> — If the function rejects/throws, result is null and error is set.

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Usage

JavaScript Example

const { attempt, attemptAsync } = require("@piyawasin/attempt");

// Synchronous
function parseNumber(str) {
  if (isNaN(Number(str))) throw new Error("Invalid number");
  return Number(str);
}

const [num, err] = attempt(parseNumber, "42");
if (err) {
  console.error("Failed to parse:", err.message);
} else {
  console.log("Parsed number:", num);
}

// Asynchronous (Function)
async function fetchData(url) {
  const res = await fetch(url);
  if (!res.ok) throw new Error("Network error");
  return res.json();
}

(async () => {
  const [data, fetchErr] = await attemptAsync(
    fetchData,
    "https://api.example.com/data"
  );
  if (fetchErr) {
    console.error("Fetch failed:", fetchErr.message);
  } else {
    console.log("Fetched data:", data);
  }
})();

// Asynchronous (Promise)
(async () => {
  const myPromise = Promise.resolve("Success!");
  const [res, err] = await attemptAsync(myPromise);
  console.log(res); // "Success!"
})();

TypeScript Example

import { attempt, attemptAsync } from "@piyawasin/attempt";

function divide(a: number, b: number): number {
  if (b === 0) throw new Error("Divide by zero");
  return a / b;
}

const [result, error] = attempt(divide, 10, 2); // result: 5, error: null

async function getUser(id: string): Promise<{ name: string }> {
  // ...fetch user
}

const [user, userErr] = await attemptAsync(getUser, "123");

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Best Practices

• Always check the error value before using the result.
• For async code, always await the result of attemptAsync.

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License

ISC