Retries async operations with exponential backoff. Useful for flaky network requests or transient failures.

retry.js

export async function retry(fn, {
  retries = 3,
  delay = 300,
  factor = 2
} = {}) {
  let attempt = 0;

  while (true) {
    try {
      return await fn();
    } catch (err) {
      if (attempt >= retries) throw err;

      const wait = delay * Math.pow(factor, attempt);
      await new Promise(r => setTimeout(r, wait));
      attempt++;
    }
  }
}

Use case:

await retry(() => fetch('/api').then(r => {
  if (!r.ok) throw new Error('fail');
  return r.json();
}));