useInfiniteQuery

function useInfiniteQuery<TQueryFnData, TError, TData, TQueryKey, TPageParam>(options: DefinedInitialDataInfiniteOptions<TQueryFnData, TError, TData, TQueryKey, TPageParam>, queryClient?: QueryClient): DefinedUseInfiniteQueryResult<TData, TError>;
function useInfiniteQuery<TQueryFnData, TError, TData, TQueryKey, TPageParam>(options: UndefinedInitialDataInfiniteOptions<TQueryFnData, TError, TData, TQueryKey, TPageParam>, queryClient?: QueryClient): UseInfiniteQueryResult<TData, TError>;
function useInfiniteQuery<TQueryFnData, TError, TData, TQueryKey, TPageParam>(options: UseInfiniteQueryOptions<TQueryFnData, TError, TData, TQueryKey, TPageParam>, queryClient?: QueryClient): UseInfiniteQueryResult<TData, TError>;

function useInfiniteQuery<TQueryFnData, TError, TData, TQueryKey, TPageParam>(options: DefinedInitialDataInfiniteOptions<TQueryFnData, TError, TData, TQueryKey, TPageParam>, queryClient?: QueryClient): DefinedUseInfiniteQueryResult<TData, TError>;

import { useInfiniteQuery } from '@tanstack/react-query'

function Projects() {
  // `data` is never `undefined`, thanks to `initialData` — even if a refetch fails, so the
  // list stays visible alongside the error.
  const { data, isError, error } = useInfiniteQuery({
    queryKey: ['projects'],
    queryFn: ({ pageParam }) => fetchProjects(pageParam),
    initialPageParam: 0,
    getNextPageParam: (lastPage) => lastPage.nextId,
    initialData: { pages: [], pageParams: [] },
  })

  return (
    <div>
      {isError ? <span>Error: {error.message}</span> : null}
      <ul>
        {data.pages.map((page) => page.projects.map((p) => <li key={p.id}>{p.name}</li>))}
      </ul>
    </div>
  )
}

function useInfiniteQuery<TQueryFnData, TError, TData, TQueryKey, TPageParam>(options: UndefinedInitialDataInfiniteOptions<TQueryFnData, TError, TData, TQueryKey, TPageParam>, queryClient?: QueryClient): UseInfiniteQueryResult<TData, TError>;

import { useInfiniteQuery } from '@tanstack/react-query'

function Projects() {
  const { data, isPending, isError, error, fetchNextPage, hasNextPage, isFetching, isFetchingNextPage } =
    useInfiniteQuery({
      queryKey: ['projects'],
      queryFn: ({ pageParam }) => fetchProjects(pageParam),
      initialPageParam: 0,
      getNextPageParam: (lastPage) => lastPage.nextId,
    })

  if (isPending) return 'Loading...'
  if (isError) return <span>Error: {error.message}</span>

  return (
    <>
      <ul>
        {data.pages.map((page) =>
          page.projects.map((project) => <li key={project.id}>{project.name}</li>),
        )}
      </ul>
      <button
        onClick={() => fetchNextPage()}
        disabled={!hasNextPage || isFetching}
      >
        {isFetchingNextPage
          ? 'Loading more...'
          : hasNextPage
            ? 'Load More'
            : 'Nothing more to load'}
      </button>
    </>
  )
}

import { useInfiniteQuery } from '@tanstack/react-query'
import { useEffect, useRef } from 'react'

function Projects() {
  const {
    data,
    isPending,
    isError,
    error,
    fetchNextPage,
    hasNextPage,
    isFetching,
    isFetchingNextPage,
  } = useInfiniteQuery({
    queryKey: ['projects'],
    queryFn: ({ pageParam }) => fetchProjects(pageParam),
    initialPageParam: 0,
    getNextPageParam: (lastPage) => lastPage.nextId,
  })

  const sentinelRef = useRef<HTMLDivElement>(null)

  useEffect(() => {
    const sentinel = sentinelRef.current
    if (sentinel == null || !hasNextPage || isFetching) return

    const observer = new IntersectionObserver(([entry]) => {
      if (entry?.isIntersecting) fetchNextPage()
    })
    observer.observe(sentinel)

    return () => observer.disconnect()
  }, [hasNextPage, isFetching, fetchNextPage])

  if (isPending) return 'Loading...'
  if (isError) return <span>Error: {error.message}</span>

  return (
    <>
      <ul>
        {data.pages.map((page) =>
          page.projects.map((project) => <li key={project.id}>{project.name}</li>),
        )}
      </ul>
      <div ref={sentinelRef}>{isFetchingNextPage ? 'Loading more...' : null}</div>
    </>
  )
}

function useInfiniteQuery<TQueryFnData, TError, TData, TQueryKey, TPageParam>(options: UseInfiniteQueryOptions<TQueryFnData, TError, TData, TQueryKey, TPageParam>, queryClient?: QueryClient): UseInfiniteQueryResult<TData, TError>;

import { useInfiniteQuery } from '@tanstack/react-query'

function Projects() {
  const { data, isPending, isError, error, fetchNextPage, hasNextPage, isFetching, isFetchingNextPage } =
    useInfiniteQuery({
      queryKey: ['projects'],
      queryFn: ({ pageParam }) => fetchProjects(pageParam),
      initialPageParam: 0,
      getNextPageParam: (lastPage) => lastPage.nextId,
    })

  if (isPending) return 'Loading...'
  if (isError) return <span>Error: {error.message}</span>

  return (
    <>
      <ul>
        {data.pages.map((page) =>
          page.projects.map((project) => <li key={project.id}>{project.name}</li>),
        )}
      </ul>
      <button
        onClick={() => fetchNextPage()}
        disabled={!hasNextPage || isFetching}
      >
        {isFetchingNextPage
          ? 'Loading more...'
          : hasNextPage
            ? 'Load More'
            : 'Nothing more to load'}
      </button>
    </>
  )
}

import { useInfiniteQuery } from '@tanstack/react-query'
import { useEffect, useRef } from 'react'

function Projects() {
  const {
    data,
    isPending,
    isError,
    error,
    fetchNextPage,
    hasNextPage,
    isFetching,
    isFetchingNextPage,
  } = useInfiniteQuery({
    queryKey: ['projects'],
    queryFn: ({ pageParam }) => fetchProjects(pageParam),
    initialPageParam: 0,
    getNextPageParam: (lastPage) => lastPage.nextId,
  })

  const sentinelRef = useRef<HTMLDivElement>(null)

  useEffect(() => {
    const sentinel = sentinelRef.current
    if (sentinel == null || !hasNextPage || isFetching) return

    const observer = new IntersectionObserver(([entry]) => {
      if (entry?.isIntersecting) fetchNextPage()
    })
    observer.observe(sentinel)

    return () => observer.disconnect()
  }, [hasNextPage, isFetching, fetchNextPage])

  if (isPending) return 'Loading...'
  if (isError) return <span>Error: {error.message}</span>

  return (
    <>
      <ul>
        {data.pages.map((page) =>
          page.projects.map((project) => <li key={project.id}>{project.name}</li>),
        )}
      </ul>
      <div ref={sentinelRef}>{isFetchingNextPage ? 'Loading more...' : null}</div>
    </>
  )
}

import { skipToken, useInfiniteQuery } from '@tanstack/react-query'

function Comments({ postId }: { postId: string | undefined }) {
  // Use `isLoading`, not `isPending`, so the loading state doesn't show while the query is disabled.
  const { data, isLoading, isError, error } = useInfiniteQuery({
    queryKey: ['post', postId, 'comments'],
    queryFn:
      postId != null
        ? ({ pageParam }) => fetchComments(postId, pageParam)
        : skipToken,
    initialPageParam: 0,
    getNextPageParam: (lastPage) => lastPage.nextId,
  })

  if (postId == null) return 'Select a post'
  if (isLoading) return 'Loading...'
  if (isError) return <span>Error: {error.message}</span>

  return (
    <ul>
      {data?.pages.map((page) => page.comments.map((c) => <li key={c.id}>{c.text}</li>))}
    </ul>
  )
}