useSWRInfinite: await setSize(totalPageCount) will not wait to load all pages.

[lovetingyuan]

Does await setSize(totalPageCount) not wait for all the page data to be requested because I used the parallel: true parameter?

[lovetingyuan]

If that's the case, I think even when using parallel requests, setSize should resolve only after all the requested data is completely received.

[Mike-Animal-Counseling]

I can reproduce the early return on SWR 2.5.1, including with parallel: false. So parallel mode isn't the deciding factor here.

When the extra pages aren't cached, setSize calls mutate with the existing data. That form of mutate starts revalidation but returns the data without awaiting it.

In a local hook test, I started with one cached page and held the next two requests open. await setSize(3) returned the one-page array while those requests were still pending. The rendered data reached three pages after the requests completed. Both parallel and sequential mode behaved this way.

If the next step needs every page, base that step on the hook's state instead:

const ready = !isValidating && !error &&
  data?.length === totalPageCount &&
  data.every(page => page !== undefined);

For example, use that condition to enable an export button, or to run a guarded effect once loading finishes. Handle error separately; resolving the size-change promise isn't proof that all pages succeeded. If getKey can return null before totalPageCount, account for that end-of-list condition too.

AI-assisted; checked with real React hooks and deferred fetch promises, including a failed-page case.