experimental_createQueryPersister

Source URL: https://tanstack.com/query/latest/docs/framework/react/plugins/createPersister

experimental_createQueryPersister

Installation

This utility comes as a separate package and is available under the '@tanstack/query-persist-client-core' import.

npm install @tanstack/query-persist-client-core

or

pnpm add @tanstack/query-persist-client-core

or

yarn add @tanstack/query-persist-client-core

or

bun add @tanstack/query-persist-client-core

Note: This util is also included in the @tanstack/react-query-persist-client package, so you do not need to install it separately if you are using that package.

Usage

• Import the experimental_createQueryPersister function
• Create a new experimental_createQueryPersister
  • you can pass any storage to it that adheres to the AsyncStorage interface - the example below uses the async-storage from React Native.
• Pass that persister as an option to your Query. This can be done either by passing it to the defaultOptions of the QueryClient or to any useQuery hook instance.
  • If you pass this persister as defaultOptions, all queries will be persisted to the provided storage. You can additionally narrow this down by passing filters. In contrast to the persistClient plugin, this will not persist the whole query client as a single item, but each query separately. As a key, the query hash is used.
  • If you provide this persister to a single useQuery hook, only this Query will be persisted.
• Note: queryClient.setQueryData() operations are not persisted, this means that if you perform an optimistic update and refresh the page before the query has been invalidated, your changes to the query data will be lost. See https://github.com/TanStack/query/issues/6310

This way, you do not need to store whole QueryClient, but choose what is worth to be persisted in your application. Each query is lazily restored (when the Query is first used) and persisted (after each run of the queryFn), so it does not need to be throttled. staleTime is also respected after restoring the Query, so if data is considered stale, it will be refetched immediately after restoring. If data is fresh, the queryFn will not run.

Garbage collecting a Query from memory does not affect the persisted data. That means Queries can be kept in memory for a shorter period of time to be more memory efficient. If they are used the next time, they will just be restored from the persistent storage again.

import AsyncStorage from '@react-native-async-storage/async-storage'
import { QueryClient } from '@tanstack/react-query'
import { experimental_createQueryPersister } from '@tanstack/query-persist-client-core'

const persister = experimental_createQueryPersister({
  storage: AsyncStorage,
  maxAge: 1000 * 60 * 60 * 12, // 12 hours
})

const queryClient = new QueryClient({
  defaultOptions: {
    queries: {
      gcTime: 1000 * 30, // 30 seconds
      persister: persister.persisterFn,
    },
  },
})

Adapted defaults

The createPersister plugin technically wraps the queryFn, so it doesn’t restore if the queryFn doesn’t run. In that way, it acts as a caching layer between the Query and the network. Thus, the networkMode defaults to 'offlineFirst' when a persister is used, so that restoring from the persistent storage can also happen even if there is no network connection.

Additional utilities

Invoking experimental_createQueryPersister returns additional utilities in addition to persisterFn for easier implementation of userland functionalities.

persistQueryByKey(queryKey: QueryKey, queryClient: QueryClient): Promise<void>

This function will persist Query to storage and key defined when creating persister. This utility might be used along setQueryData to persist optimistic update to storage without waiting for invalidation.

const persister = experimental_createQueryPersister({
  storage: AsyncStorage,
  maxAge: 1000 * 60 * 60 * 12, // 12 hours
})

const queryClient = useQueryClient()

useMutation({
  mutationFn: updateTodo,
  onMutate: async (newTodo) => {
    ...
    // Optimistically update to the new value
    queryClient.setQueryData(['todos'], (old) => [...old, newTodo])
    // And persist it to storage
    persister.persistQueryByKey(['todos'], queryClient)
    ...
  },
})

retrieveQuery<T>(queryHash: string): Promise<T | undefined>

This function would attempt to retrieve persisted query by queryHash. If query is expired, busted or malformed it would be removed from the storage instead, and undefined would be returned.

persisterGc(): Promise<void>

This function can be used to sporadically clean up stoage from expired, busted or malformed entries.

For this function to work, your storage must expose entries method that would return a key-value tuple array. For example Object.entries(localStorage) for localStorage or entries from idb-keyval.

restoreQueries(queryClient: QueryClient, filters): Promise<void>

This function can be used to restore queries that are currently stored by persister. For example when your app is starting up in offline mode, or you want all or only specific data from previous session to be immediately available without intermediate loading state.

The filter object supports the following properties:

• queryKey?: QueryKey
  • Set this property to define a query key to match on.
• exact?: boolean
  • If you don’t want to search queries inclusively by query key, you can pass the exact: true option to return only the query with the exact query key you have passed.

For this function to work, your storage must expose entries method that would return a key-value tuple array. For example Object.entries(localStorage) for localStorage or entries from idb-keyval.

API

experimental_createQueryPersister

experimental_createQueryPersister(options: StoragePersisterOptions)

Options

export interface StoragePersisterOptions {
  /** The storage client used for setting and retrieving items from cache.
   * For SSR pass in `undefined`.
   */
  storage: AsyncStorage | Storage | undefined | null
  /**
   * How to serialize the data to storage.
   * @default `JSON.stringify`
   */
  serialize?: (persistedQuery: PersistedQuery) => string
  /**
   * How to deserialize the data from storage.
   * @default `JSON.parse`
   */
  deserialize?: (cachedString: string) => PersistedQuery
  /**
   * A unique string that can be used to forcefully invalidate existing caches,
   * if they do not share the same buster string
   */
  buster?: string
  /**
   * The max-allowed age of the cache in milliseconds.
   * If a persisted cache is found that is older than this
   * time, it will be discarded
   * @default 24 hours
   */
  maxAge?: number
  /**
   * Prefix to be used for storage key.
   * Storage key is a combination of prefix and query hash in a form of `prefix-queryHash`.
   */
  prefix?: string
  /**
   * If set to `true`, the query will refetch on successful query restoration if the data is stale.
   * If set to `false`, the query will not refetch on successful query restoration.
   * If set to `'always'`, the query will always refetch on successful query restoration.
   * Defaults to `true`.
   */
  refetchOnRestore?: boolean | 'always'
  /**
   * Filters to narrow down which Queries should be persisted.
   */
  filters?: QueryFilters
}

interface AsyncStorage<TStorageValue = string> {
  getItem: (key: string) => MaybePromise<TStorageValue | undefined | null>
  setItem: (key: string, value: TStorageValue) => MaybePromise<unknown>
  removeItem: (key: string) => MaybePromise<void>
  entries?: () => MaybePromise<Array<[key: string, value: TStorageValue]>>
}

The default options are:

{
  prefix = 'tanstack-query',
  maxAge = 1000 * 60 * 60 * 24,
  serialize = JSON.stringify,
  deserialize = JSON.parse,
  refetchOnRestore = true,
}