Resilient API Requests with Exponential Backoff

async function fetchWithExponentialBackoff(url, options = {}, retries = 3, delay = 1000) {
  for (let i = 0; i < retries; i++) {
    try {
      const response = await fetch(url, options);
      if (!response.ok) {
        // Treat non-OK responses (e.g., 5xx, 429 Too Many Requests) as retriable errors
        // You might want to fine-tune which statuses are retriable
        throw new Error(`HTTP error! status: ${response.status}`);
      }
      return response; // Success!
    } catch (error) {
      console.warn(`Request failed (attempt ${i + 1}/${retries}): ${error.message}`);
      if (i < retries - 1) {
        const backoffDelay = delay * Math.pow(2, i) + Math.random() * 1000; // Exponential + jitter
        console.log(`Retrying in ${backoffDelay}ms...`);
        await new Promise(resolve => setTimeout(resolve, backoffDelay));
      } else {
        throw error; // Last attempt failed, re-throw the error
      }
    }
  }
}

// Example Usage:
(async () => {
  try {
    const data = await fetchWithExponentialBackoff('https://jsonplaceholder.typicode.com/posts/1', {
      method: 'GET'
    }, 5); // Try up to 5 times
    const json = await data.json();
    console.log('Successfully fetched data:', json);
  } catch (error) {
    console.error('Failed to fetch data after multiple retries:', error);
  }

  // Example of a potentially failing request (e.g., intentionally bad URL or rate-limited mock)
  // Note: jsonplaceholder might not return 5xx errors for non-existent routes,
  // so this example assumes a service that might transiently fail.
  try {
    const failingData = await fetchWithExponentialBackoff('https://httpstat.us/503', {}, 3, 500); // Simulate 503 error
    const text = await failingData.text(); // 503 response body
    console.log('Successfully fetched failing data (should not happen if 503 is always returned):', text);
  } catch (error) {
    console.error('Expected failure for 503 simulation:', error);
  }
})();