88Implement retry with exponential backoff and jitter

Implement two functions:

computeDelay(attempt, { baseDelay = 100, factor = 2, maxDelay = 10000, jitter = "full", random = Math.random }) returns the wait in ms before retry number attempt (0 for the first retry):

• the exponential part is min(maxDelay, baseDelay * factor ** attempt);
• jitter: "none" returns it unchanged; "full" returns random() * exp; "equal" returns exp / 2 + random() * exp / 2.

retryWithBackoff(fn, options) calls the async fn(attempt) and retries failures:

• options: retries = 3 (retries after the first try), the computeDelay options, shouldRetry, onRetry(error, attempt, delay), signal, and sleep = (ms) => new Promise(…) (injectable for tests);
• by default, retry network errors (TypeError) and errors with status 408, 429 or 5xx; never retry other 4xx;
• if an error has retryAfter (milliseconds, for example parsed from a Retry-After header), wait at least that long;
• stop and reject with signal.reason when signal is aborted;
• reject with the last error when retries run out.

const data = await retryWithBackoff(() => api.get("/report"), { retries: 5, baseDelay: 200, maxDelay: 5000 });