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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/TanStack/query/llms.txt

Use this file to discover all available pages before exploring further.

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useQueryClient

The useQueryClient hook returns the current QueryClient instance from the React context. It provides access to all QueryClient methods for manual query and mutation management.

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Import

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

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Signature

function useQueryClient(queryClient?: QueryClient): QueryClient

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Parameters

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queryClient
QueryClient
Optional QueryClient instance to use. If provided, this client will be returned instead of the context client. Useful for testing or when you want to use a different client instance.

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Returns

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queryClient
QueryClient
required
The QueryClient instance from context (or the provided queryClient parameter)

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Examples

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Basic Usage

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

function Component() {
  const queryClient = useQueryClient()
  
  const handleInvalidate = () => {
    queryClient.invalidateQueries({ queryKey: ['posts'] })
  }
  
  return <button onClick={handleInvalidate}>Refresh Posts</button>
}

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Invalidating Queries

import { useQueryClient, useMutation } from '@tanstack/react-query'

function CreatePost() {
  const queryClient = useQueryClient()
  
  const mutation = useMutation({
    mutationFn: createPost,
    onSuccess: () => {
      // Invalidate and refetch posts after creating a new one
      queryClient.invalidateQueries({ queryKey: ['posts'] })
    },
  })
  
  return <button onClick={() => mutation.mutate(newPost)}>Create</button>
}

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Prefetching Queries

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

function PostLink({ id }: { id: number }) {
  const queryClient = useQueryClient()
  
  const handleMouseEnter = () => {
    // Prefetch the post when hovering
    queryClient.prefetchQuery({
      queryKey: ['post', id],
      queryFn: () => fetchPost(id),
    })
  }
  
  return (
    <Link to={`/posts/${id}`} onMouseEnter={handleMouseEnter}>
      View Post
    </Link>
  )
}

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Setting Query Data Manually

import { useQueryClient, useMutation } from '@tanstack/react-query'

function UpdatePost({ id }: { id: number }) {
  const queryClient = useQueryClient()
  
  const mutation = useMutation({
    mutationFn: updatePost,
    onSuccess: (updatedPost) => {
      // Manually update the cache with the new data
      queryClient.setQueryData(['post', id], updatedPost)
      
      // Update the posts list
      queryClient.setQueryData<Post[]>(['posts'], (old) => {
        return old?.map((post) =>
          post.id === id ? updatedPost : post
        )
      })
    },
  })
  
  return <button onClick={() => mutation.mutate(data)}>Update</button>
}

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Accessing Query Cache

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

function PostStatus({ id }: { id: number }) {
  const queryClient = useQueryClient()
  
  const handleCheck = () => {
    // Get cached data without triggering a fetch
    const cachedPost = queryClient.getQueryData(['post', id])
    
    // Get query state
    const queryState = queryClient.getQueryState(['post', id])
    
    console.log('Cached:', cachedPost)
    console.log('State:', queryState)
  }
  
  return <button onClick={handleCheck}>Check Cache</button>
}

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Canceling Queries

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

function Component() {
  const queryClient = useQueryClient()
  
  const handleCancel = () => {
    // Cancel all outgoing queries
    queryClient.cancelQueries({ queryKey: ['posts'] })
  }
  
  return <button onClick={handleCancel}>Cancel Requests</button>
}

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Removing Queries

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

function Component() {
  const queryClient = useQueryClient()
  
  const handleLogout = () => {
    // Remove all queries from cache
    queryClient.removeQueries()
    
    // Or remove specific queries
    queryClient.removeQueries({ queryKey: ['user'] })
  }
  
  return <button onClick={handleLogout}>Logout</button>
}

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Resetting Queries

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

function Component() {
  const queryClient = useQueryClient()
  
  const handleReset = () => {
    // Reset queries to their initial state
    queryClient.resetQueries({ queryKey: ['posts'] })
  }
  
  return <button onClick={handleReset}>Reset</button>
}

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Accessing Mutation Cache

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

function MutationStatus() {
  const queryClient = useQueryClient()
  const mutationCache = queryClient.getMutationCache()
  
  const handleCheck = () => {
    // Get all mutations
    const mutations = mutationCache.getAll()
    
    // Get pending mutations
    const pending = mutationCache.findAll({ status: 'pending' })
    
    console.log('All mutations:', mutations)
    console.log('Pending mutations:', pending)
  }
  
  return <button onClick={handleCheck}>Check Mutations</button>
}

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Building a Refresh Button

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

function RefreshButton() {
  const queryClient = useQueryClient()
  const [isRefreshing, setIsRefreshing] = useState(false)
  
  const handleRefresh = async () => {
    setIsRefreshing(true)
    try {
      await queryClient.invalidateQueries()
    } finally {
      setIsRefreshing(false)
    }
  }
  
  return (
    <button onClick={handleRefresh} disabled={isRefreshing}>
      {isRefreshing ? 'Refreshing...' : 'Refresh All'}
    </button>
  )
}

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With Custom QueryClient

import { useQueryClient, QueryClient } from '@tanstack/react-query'

function Component() {
  const customClient = new QueryClient()
  
  // Use custom client instead of context client
  const queryClient = useQueryClient(customClient)
  
  return <div>{/* ... */}</div>
}

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Common Methods

The QueryClient instance provides many useful methods:

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Query Methods

  • getQueryData(queryKey) - Get cached query data
  • setQueryData(queryKey, updater) - Set query data manually
  • getQueryState(queryKey) - Get query state information
  • invalidateQueries(filters) - Mark queries as stale
  • refetchQueries(filters) - Refetch queries
  • cancelQueries(filters) - Cancel outgoing queries
  • removeQueries(filters) - Remove queries from cache
  • resetQueries(filters) - Reset queries to initial state
  • prefetchQuery(options) - Prefetch a query
  • fetchQuery(options) - Fetch and return query data

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Mutation Methods

  • getMutationCache() - Get the mutation cache instance
  • isMutating(filters) - Check if mutations are running

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Cache Methods

  • getQueryCache() - Get the query cache instance
  • clear() - Clear all caches
  • mount() - Mount the client
  • unmount() - Unmount the client

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Notes

  • The hook must be used within a QueryClientProvider.
  • If no QueryClient is found in context and none is provided, an error is thrown.
  • The optional queryClient parameter is primarily useful for testing or special use cases.
  • Most query and mutation hooks accept an optional queryClient parameter, making this hook unnecessary in many cases.
  • However, this hook is essential when you need to imperatively interact with the query cache outside of the standard hook lifecycle.

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