382 lines
9.7 KiB
Markdown
382 lines
9.7 KiB
Markdown
---
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id: useQuery
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title: useQuery
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redirect_from:
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- framework/react/reference/useQuery
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---
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## Call Signature
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```ts
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function useQuery<TQueryFnData, TError, TData, TQueryKey>(options, queryClient?): DefinedUseQueryResult<TData, TError>;
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```
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Defined in: [packages/react-query/src/useQuery.ts:50](https://github.com/TanStack/query/blob/main/packages/react-query/src/useQuery.ts#L50)
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This overload is selected when `initialData` is set, so the resulting `data` is never `undefined`.
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### Type Parameters
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#### TQueryFnData
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`TQueryFnData` = `unknown`
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#### TError
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`TError` = `Error`
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#### TData
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`TData` = `TQueryFnData`
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#### TQueryKey
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`TQueryKey` *extends* readonly `unknown`[] = readonly `unknown`[]
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### Parameters
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#### options
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[`DefinedInitialDataOptions`](../type-aliases/DefinedInitialDataOptions.md)\<`TQueryFnData`, `TError`, `TData`, `TQueryKey`\>
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The [DefinedInitialDataOptions](../type-aliases/DefinedInitialDataOptions.md) to use — everything you can pass to `useQuery`, with `initialData` set.
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#### queryClient?
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[`QueryClient`](../classes/QueryClient.md)
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Use this to use a custom `QueryClient`. Otherwise, the one from the nearest context will
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be used.
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### Returns
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[`DefinedUseQueryResult`](../type-aliases/DefinedUseQueryResult.md)\<`TData`, `TError`\>
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The current query result, typed so that `status` is `success` — or `error` if a fetch attempt
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fails while keeping the existing data (`status` never resolves to `pending` in this overload's type,
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since `initialData` guarantees data upfront). `isSuccess`/`isError` are derived booleans for convenience.
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### See
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[queryOptions](queryOptions.md) to share these options between `useQuery` and imperative APIs like `queryClient.query`.
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### Example
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```tsx
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import { useQuery } from '@tanstack/react-query'
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function Posts() {
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// `data` is `Post[]`, never `undefined`, thanks to `initialData` — even if a refetch fails,
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// so the list stays visible alongside the error.
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const { data, isError, error } = useQuery({
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queryKey: ['posts'],
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queryFn: fetchPosts,
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initialData: [],
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})
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return (
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<div>
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{isError ? <span>Error: {error.message}</span> : null}
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<ul>
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{data.map((post) => <li key={post.id}>{post.title}</li>)}
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</ul>
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</div>
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)
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}
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```
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## Call Signature
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```ts
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function useQuery<TQueryFnData, TError, TData, TQueryKey>(options, queryClient?): UseQueryResult<TData, TError>;
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```
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Defined in: [packages/react-query/src/useQuery.ts:117](https://github.com/TanStack/query/blob/main/packages/react-query/src/useQuery.ts#L117)
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### Type Parameters
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#### TQueryFnData
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`TQueryFnData` = `unknown`
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#### TError
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`TError` = `Error`
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#### TData
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`TData` = `TQueryFnData`
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#### TQueryKey
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`TQueryKey` *extends* readonly `unknown`[] = readonly `unknown`[]
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### Parameters
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#### options
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[`UndefinedInitialDataOptions`](../type-aliases/UndefinedInitialDataOptions.md)\<`TQueryFnData`, `TError`, `TData`, `TQueryKey`\>
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The [UndefinedInitialDataOptions](../type-aliases/UndefinedInitialDataOptions.md) to use — everything you can pass to `useQuery`.
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#### queryClient?
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[`QueryClient`](../classes/QueryClient.md)
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Use this to use a custom `QueryClient`. Otherwise, the one from the nearest context will
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be used.
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### Returns
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[`UseQueryResult`](../type-aliases/UseQueryResult.md)\<`TData`, `TError`\>
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The current query result. `status` is `pending` if there is no cached data to display, `error` if
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the last fetch attempt failed, or `success` if the query has data to display. `isPending`/`isSuccess`/`isError`
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are derived booleans for convenience.
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### See
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[queryOptions](queryOptions.md) to share these options between `useQuery` and imperative APIs like `queryClient.query`.
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### Examples
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```tsx
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import { useQuery } from '@tanstack/react-query'
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function Posts() {
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const { status, data, error, isFetching } = useQuery({
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queryKey: ['posts'],
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queryFn: fetchPosts,
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})
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if (status === 'pending') return 'Loading...'
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if (status === 'error') return <span>Error: {error.message}</span>
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return (
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<div>
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<ul>
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{data.map((post) => (
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<li key={post.id}>{post.title}</li>
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))}
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</ul>
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<div>{isFetching ? 'Background Updating...' : ' '}</div>
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</div>
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)
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}
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```
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The same query, checking `isPending`/`isError` instead of `status` — pick whichever reads better to you:
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```tsx
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import { useQuery } from '@tanstack/react-query'
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function Posts() {
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const { isPending, isError, data, error } = useQuery({
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queryKey: ['posts'],
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queryFn: fetchPosts,
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})
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if (isPending) return 'Loading...'
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if (isError) return <span>Error: {error.message}</span>
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return (
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<ul>
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{data.map((post) => <li key={post.id}>{post.title}</li>)}
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</ul>
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)
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}
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```
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## Call Signature
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```ts
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function useQuery<TQueryFnData, TError, TData, TQueryKey>(options, queryClient?): UseQueryResult<TData, TError>;
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```
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Defined in: [packages/react-query/src/useQuery.ts:281](https://github.com/TanStack/query/blob/main/packages/react-query/src/useQuery.ts#L281)
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### Type Parameters
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#### TQueryFnData
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`TQueryFnData` = `unknown`
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#### TError
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`TError` = `Error`
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#### TData
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`TData` = `TQueryFnData`
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#### TQueryKey
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`TQueryKey` *extends* readonly `unknown`[] = readonly `unknown`[]
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### Parameters
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#### options
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[`UseQueryOptions`](../interfaces/UseQueryOptions.md)\<`TQueryFnData`, `TError`, `TData`, `TQueryKey`\>
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The [UseQueryOptions](../interfaces/UseQueryOptions.md) to use — everything you can pass to `useQuery`.
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#### queryClient?
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[`QueryClient`](../classes/QueryClient.md)
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Use this to use a custom `QueryClient`. Otherwise, the one from the nearest context will
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be used.
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### Returns
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[`UseQueryResult`](../type-aliases/UseQueryResult.md)\<`TData`, `TError`\>
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The current query result. `status` is `pending` if there is no cached data to display, `error` if
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the last fetch attempt failed, or `success` if the query has data to display. `isPending`/`isSuccess`/`isError`
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are derived booleans for convenience.
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### See
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[queryOptions](queryOptions.md) to share these options between `useQuery` and imperative APIs like `queryClient.query`.
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### Examples
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```tsx
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import { useQuery } from '@tanstack/react-query'
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function Posts() {
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const { status, data, error, isFetching } = useQuery({
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queryKey: ['posts'],
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queryFn: fetchPosts,
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})
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if (status === 'pending') return 'Loading...'
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if (status === 'error') return <span>Error: {error.message}</span>
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return (
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<div>
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<ul>
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{data.map((post) => (
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<li key={post.id}>{post.title}</li>
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))}
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</ul>
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<div>{isFetching ? 'Background Updating...' : ' '}</div>
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</div>
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)
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}
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```
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`select` derives whatever `data` a component needs from the cached value, without changing what's
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actually stored in the cache — the cache still holds the full `Post[]`, but `data` here is a `number`:
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```tsx
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import { useQuery } from '@tanstack/react-query'
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function PostCount() {
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const { data, isPending, isError, error } = useQuery({
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queryKey: ['posts'],
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queryFn: fetchPosts,
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select: (posts) => posts.length,
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})
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if (isPending) return 'Loading...'
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if (isError) return <span>Error: {error.message}</span>
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return <span>{data} posts</span>
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}
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```
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A dependent query, only enabled once `postId` is set — use `isLoading`, not `isPending`, so the
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loading state doesn't show while the query is disabled:
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```tsx
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import { useQuery } from '@tanstack/react-query'
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function Post({ postId }: { postId: number | undefined }) {
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const { data, isLoading, isError, error } = useQuery({
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queryKey: ['post', postId],
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queryFn: () => fetchPost(postId!),
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enabled: postId != null,
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})
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if (postId == null) return 'Select a post'
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if (isLoading) return 'Loading...'
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if (isError) return <span>Error: {error.message}</span>
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return <h1>{data?.title}</h1>
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}
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```
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The same dependent query, type safe: `skipToken` disables the query without needing the
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non-null assertion above, since `queryFn` is only ever called when `postId` is defined.
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`refetch` doesn't work while `queryFn` is `skipToken` — use `enabled: false` instead if you
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need to trigger the query manually:
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```tsx
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import { skipToken, useQuery } from '@tanstack/react-query'
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function Post({ postId }: { postId: number | undefined }) {
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const { data, isLoading, isError, error } = useQuery({
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queryKey: ['post', postId],
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queryFn: postId != null ? () => fetchPost(postId) : skipToken,
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})
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if (postId == null) return 'Select a post'
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if (isLoading) return 'Loading...'
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if (isError) return <span>Error: {error.message}</span>
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return <h1>{data?.title}</h1>
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}
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```
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Seeding a detail query from an already-cached list, to skip the loading state:
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```tsx
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import { useQuery, useQueryClient } from '@tanstack/react-query'
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function Post({ postId }: { postId: number }) {
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const queryClient = useQueryClient()
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const { data, isError, error } = useQuery({
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queryKey: ['post', postId],
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queryFn: () => fetchPost(postId),
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initialData: () =>
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queryClient
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.getQueryData<Array<Post>>(['posts'])
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?.find((post) => post.id === postId),
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})
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if (isError) return <span>Error: {error.message}</span>
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return <h1>{data?.title}</h1>
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}
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```
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Paginated data, keeping the previous page's data visible while the next page loads:
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```tsx
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import { keepPreviousData, useQuery } from '@tanstack/react-query'
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import { useState } from 'react'
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function Posts() {
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const [page, setPage] = useState(0)
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const { data, isPlaceholderData, isError, error } = useQuery({
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queryKey: ['posts', page],
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queryFn: () => fetchPosts(page),
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placeholderData: keepPreviousData,
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})
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if (isError) return <span>Error: {error.message}</span>
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return (
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<div>
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<ul>
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{data?.map((post) => <li key={post.id}>{post.title}</li>)}
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</ul>
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<button
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disabled={isPlaceholderData}
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onClick={() => setPage((old) => old + 1)}
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>
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Next Page
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</button>
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</div>
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)
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}
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```
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