Retry Once

On network failure, try the same request one more time — keep it simple.

Flaky networks sometimes fail once. A single retry can help. Do not retry forever, and prefer not retrying clear HTTP 4xx errors. This lab forces a bad host first (optional), then a real GET. 

Attempt log appears here.

Run a GET that may retry once on network failure.

Important JavaScript

async function fetchOnce(url) {
  const response = await fetch(url);
  if (!response.ok) {
    throw new Error("HTTP " + response.status);
  }
  return response.json();
}

async function fetchWithRetry(url) {
  try {
    return await fetchOnce(url);
  } catch (error) {
    if (String(error.message).indexOf("HTTP ") === 0) {
      throw error; // do not retry clear HTTP errors
    }
    return fetchOnce(url); // one network retry
  }
}