https://pressthink.org/j/rosen-archive/frontend/utils/raceTimeout.js?v=3.8.36

1/**
2 * Race a promise against a timeout.
3 *
4 * One settle-once timer guards two contracts, selected by `rejectOnTimeout`:
5 *
6 *   resolve-mode (default): resolve to the promise's value, or to `fallback`
7 *     if it rejects or does not settle within `ms`. Never rejects. Bounds a
8 *     check that must not stall work a fallback can already satisfy
9 *     (archiveService's version check).
10 *
11 *   reject-mode (`rejectOnTimeout: true`): resolve to the promise's value;
12 *     reject with the promise's own error if it rejects, or with a timeout
13 *     Error if it does not settle within `ms`. Surfaces a stall as a failure
14 *     the caller can fall back from (idbCache's idb-keyval import race).
15 *
16 * The timer is intentionally left ref'd: an unref'd timer that is the only
17 * pending work never fires (the event loop idles past it), so a hung promise
18 * would never time out. It is cleared as soon as either side settles.
19 *
20 * @template T
21 * @param {Promise<T>} promise
22 * @param {number} ms
23 * @param {{ fallback?: T, rejectOnTimeout?: boolean }} [options]
24 * @returns {Promise<T>}
25 */
26export const raceTimeout = (promise, ms, { fallback, rejectOnTimeout = false } = {}) =>
27  new Promise((resolve, reject) => {
28    let settled = false;
29    const finishResolve = (value) => {
30      if (settled) return;
31      settled = true;
32      clearTimeout(timer);
33      resolve(value);
34    };
35    const finishReject = (err) => {
36      if (settled) return;
37      settled = true;
38      clearTimeout(timer);
39      reject(err);
40    };
41    const timer = setTimeout(() => {
42      if (rejectOnTimeout) finishReject(new Error(`timed out after ${ms}ms`));
43      else finishResolve(fallback);
44    }, ms);
45    promise.then(
46      finishResolve,
47      (err) => (rejectOnTimeout ? finishReject(err) : finishResolve(fallback)),
48    );
49  });