Function fetchFn

packages/query-core/src/infiniteQueryBehavior.ts:28–111

()

      let currentPage = 0

      const fetchFn = async () => {
        let cancelled = false
        const addSignalProperty = (object: unknown) => {
          addConsumeAwareSignal(
            object,
            () => context.signal,
            () => (cancelled = true),
          )
        }

        const queryFn = ensureQueryFn(context.options, context.fetchOptions)

        // Create function to fetch a page
        const fetchPage = async (
          data: InfiniteData<unknown>,
          param: unknown,
          previous?: boolean,
        ): Promise<InfiniteData<unknown>> => {
          if (cancelled) {
            return Promise.reject(context.signal.reason)
          }

          if (param == null && data.pages.length) {
            return Promise.resolve(data)
          }

          const createQueryFnContext = () => {
            const queryFnContext: OmitKeyof<
              QueryFunctionContext<QueryKey, unknown>,
              'signal'
            > = {
              client: context.client,
              queryKey: context.queryKey,
              pageParam: param,
              direction: previous ? 'backward' : 'forward',
              meta: context.options.meta,
            }
            addSignalProperty(queryFnContext)
            return queryFnContext as QueryFunctionContext<QueryKey, unknown>
          }

          const queryFnContext = createQueryFnContext()

          const page = await queryFn(queryFnContext)

          const { maxPages } = context.options
          const addTo = previous ? addToStart : addToEnd

          return {
            pages: addTo(data.pages, page, maxPages),
            pageParams: addTo(data.pageParams, param, maxPages),
          }
        }

        // fetch next / previous page?
        if (direction && oldPages.length) {
          const previous = direction === 'backward'
          const pageParamFn = previous ? getPreviousPageParam : getNextPageParam