How do I handle async/await errors properly in JavaScript?

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How do I handle async/await errors properly in JavaScript? | Dev Overflow

David Kim

How do I handle async/await errors properly in JavaScript?

asked 2 months ago

4.2K

I've been using async/await in my Node.js app but I keep running into unhandled promise rejections. Here's my current code:

async function fetchData() {
  const res = await fetch('https://api.example.com/data');
  const json = await res.json();
  return json;
}

What's the correct pattern for catching errors? Should I use try/catch everywhere or is there a better approach?

javascript

nodejs

2 Answers

Jake Thornton

• answered 1 months ago

The cleanest pattern is wrapping with try/catch:

async function fetchData() {
  try {
    const res = await fetch('https://api.example.com/data');
    if (!res.ok) throw new Error(`HTTP error: ${res.status}`);
    return await res.json();
  } catch (err) {
    console.error('fetchData failed:', err);
    throw err; // re-throw if the caller needs to handle it
  }
}

If you want to avoid try/catch everywhere, you can write a small wrapper:

const to = (p) => p.then(data => [null, data]).catch(err => [err, null]);

const [err, data] = await to(fetchData());
if (err) { /* handle */ }

The to() pattern (from go-style error handling) is popular in large codebases because it keeps error handling explicit without nesting.

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How do I handle async/await errors properly in JavaScript?

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