1function fetchRetry(url, options = {}, retries = 3, backoff = 300) {
2  /* 1 */
3  const retryCodes = [408, 500, 502, 503, 504, 522, 524]
4  return fetch(url, options)
5    .then(res => {
6      if (res.ok) return res.json()
7
8      if (retries > 0 && retryCodes.includes(res.status)) {
9        setTimeout(() => {
10          /* 2 */
11          return fetchRetry(url, options, retries - 1, backoff * 2) /* 3 */
12        }, backoff) /* 2 */
13      } else {
14        throw new Error(res)
15      }
16    })
17    .catch(console.error)
18}
19