Find out whether fetchPreviousPage or fetchNextPage caused the error using a bi-directional useInfiniteQuery

[suzaninfi]

When you're using a bi-directional useInfiniteQuery, and an error occurs while fetching, is there any way to know whether that error was caused by fetchPreviousPage or fetchNextPage (or neither in case of initial load)?

For example, I'm using 'previous' and 'next' buttons to fetch the previous or next page, and would like to hide the 'previous' button when an error occured while fetching the previous page (but not the 'next' button).

One of my ideas was to give an extra argument to fetchNextPage or fetchPreviousPage, to tell the query function which of these was used so it can throw a custom error. But I was wondering if there was a simpler way. In addition, I'm not sure how to add extra arguments to these without overwriting the pageParam.

My current code looks something like this, calling fetchNextPage and fetchPreviousPage on the buttons.

  const {
    data,
    error,
    fetchNextPage,
    fetchPreviousPage,
  } = useInfiniteQuery<{journeys: Journey[]; offset: number}, Error>(
    ['journeys', JSON.stringify(settings)],
    (data) => fetchJourneys(data.pageParam || 0, settings),
    {
      getNextPageParam: (lastPage) => {
        return lastPage.offset + 1;
      },
      getPreviousPageParam: (lastPage) => {
        return lastPage.offset - 1;
      },
    },
  );

Thank you! 🙏

[TkDodo]

not that I know of. We do have this information though because we are computing isFetchingNextPage from it:

query/packages/query-core/src/infiniteQueryObserver.ts

Lines 151 to 156 in 357ec04

	isFetchingNextPage:
	state.fetchStatus === 'fetching' &&
	state.fetchMeta?.fetchMore?.direction === 'forward',
	isFetchingPreviousPage:
	state.fetchStatus === 'fetching' &&
	state.fetchMeta?.fetchMore?.direction === 'backward',

question is: what would be a good way to expose it 🤔

[suzaninfi]

Hm, maybe it would be useful to have access to the fetch direction? Not sure if that has downsides. Guess it's only relevant if you're working bidirectionally

[TkDodo]

thought so, too, but it would have to be lastFetchDirection or something ...