const sleep = (ms: number) =>
  new Promise<void>((resolve) => setTimeout(resolve, ms));

export const retry = async <T>(
  fn: () => Promise<T>,
  retries = 3,
  delayMs = 300,
): Promise<T> => {
  let error: unknown;
  for (let i = 0; i < retries; i++) {
    try {
      return await fn();
    } catch (e) {
      error = e;
      if (i < retries - 1) {
        await sleep(delayMs * (i + 1));
      }
    }
  }
  throw error;
};

// Usage
const data = await retry(
  () => fetch('/api/data').then(r => r.json()),
  3,    // max retries
  500   // base delay in ms
);