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import React from 'react'
import Link from 'next/link'
import { useInView } from 'react-intersection-observer'
import {
useInfiniteQuery,
QueryClient,
QueryClientProvider,
} from '@tanstack/react-query'
import { ReactQueryDevtools } from '@tanstack/react-query-devtools'
const queryClient = new QueryClient()
export default function App() {
return (
<QueryClientProvider client={queryClient}>
<Example />
</QueryClientProvider>
)
}
function Example() {
const { ref, inView } = useInView()
const {
status,
data,
error,
isFetching,
isFetchingNextPage,
isFetchingPreviousPage,
fetchNextPage,
fetchPreviousPage,
hasNextPage,
hasPreviousPage,
} = useInfiniteQuery({
queryKey: ['projects'],
queryFn: async ({
pageParam,
}): Promise<{
data: Array<{ name: string; id: number }>
previousId: number
nextId: number
}> => {
const response = await fetch(`/api/projects?cursor=${pageParam}`)
return await response.json()
},
initialPageParam: 0,
getPreviousPageParam: (firstPage) => firstPage.previousId,
getNextPageParam: (lastPage) => lastPage.nextId,
})
React.useEffect(() => {
if (inView) {
fetchNextPage()
}
}, [fetchNextPage, inView])
return (
<div>
<h1>Infinite Loading</h1>
{status === 'pending' ? (
<p>Loading...</p>
) : status === 'error' ? (
<span>Error: {error.message}</span>
) : (
<>
<div>
<button
onClick={() => fetchPreviousPage()}
disabled={!hasPreviousPage || isFetchingPreviousPage}
>
{isFetchingPreviousPage
? 'Loading more...'
: hasPreviousPage
? 'Load Older'
: 'Nothing more to load'}
</button>
</div>
{data.pages.map((page) => (
<React.Fragment key={page.nextId}>
{page.data.map((project) => (
<p
style={{
border: '1px solid gray',
borderRadius: '5px',
padding: '10rem 1rem',
background: `hsla(${project.id * 30}, 60%, 80%, 1)`,
}}
key={project.id}
>
{project.name}
</p>
))}
</React.Fragment>
))}
<div>
<button
ref={ref}
onClick={() => fetchNextPage()}
disabled={!hasNextPage || isFetchingNextPage}
>
{isFetchingNextPage
? 'Loading more...'
: hasNextPage
? 'Load Newer'
: 'Nothing more to load'}
</button>
</div>
<div>
{isFetching && !isFetchingNextPage
? 'Background Updating...'
: null}
</div>
</>
)}
<hr />
<Link href="/about">Go to another page</Link>
<ReactQueryDevtools initialIsOpen />
</div>
)
}
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