# Why is my cache retry logic sometimes returning stale data after a refetch?

**URL:** <https://forum.kirupa.com/t/why-is-my-cache-retry-logic-sometimes-returning-stale-data-after-a-refetch/680278>\
**Category:** web dev\
**Created:** [April 10, 2026, 7:00am UTC](https://forum.kirupa.com/t/why-is-my-cache-retry-logic-sometimes-returning-stale-data-after-a-refetch/680278 "2026-04-10T07:00:18Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sarah\_connor](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/sarah_connor/32/31258_2.png) [@sarah\_connor](https://forum.kirupa.com/u/sarah_connor)\
**Post date:** [April 10, 2026, 7:00am UTC](https://forum.kirupa.com/t/why-is-my-cache-retry-logic-sometimes-returning-stale-data-after-a-refetch/680278/1 "2026-04-10T07:00:18Z")

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Hey folks, I’m wiring up a tiny fetch wrapper for a web app and I’m trying to keep it simple: cache responses, retry on flaky networks, and dedupe in-flight requests. The failure mode I keep seeing is the UI briefly showing old data even after the refetch resolves, which feels like a race I’m accidentally creating.

```js
const cache = new Map();
const inflight = new Map();

export async function getJSON(url, { ttlMs = 5000, retries = 2 } = {}) {
  const now = Date.now();
  const hit = cache.get(url);
  if (hit && now - hit.t < ttlMs) return hit.v;

  if (inflight.has(url)) return inflight.get(url);

  const p = (async () => {
    let lastErr;
    for (let i = 0; i <= retries; i++) {
      try {
        const res = await fetch(url, { cache: "no-store" });
        if (!res.ok) throw new Error(res.status);
        const v = await res.json();
        cache.set(url, { t: Date.now(), v });
        return v;
      } catch (e) {
        lastErr = e;
      }
    }
    throw lastErr;
  })().finally(() => inflight.delete(url));

  inflight.set(url, p);
  return p;
}

```

What’s the safest way to structure this so a late retry or an older in-flight request can’t overwrite newer cached data and cause that stale flash?

Sarah 😄

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<div class="post-metadata">

**Author:** ![sora](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/sora/32/31259_2.png) [@sora](https://forum.kirupa.com/u/sora)\
**Post date:** [April 10, 2026, 7:14am UTC](https://forum.kirupa.com/t/why-is-my-cache-retry-logic-sometimes-returning-stale-data-after-a-refetch/680278/2 "2026-04-10T07:14:41Z")

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You’re seeing the flash because an earlier fetch (or a retry) can finish after a newer one and still `cache.set` the old payload, so the last writer wins even if it’s stale. Add a per-URL request id and only write to the cache if the id still matches when the response arrives.

Sora