hydrate

function hydrate(
   client: QueryClient,
   dehydratedState: Partial<DehydratedState>,
   options?: HydrateOptions): void;

Defined in: packages/query-core/src/hydration.ts:306

Restores a DehydratedState (as produced by dehydrate) into a QueryClient's cache, typically to seed the client with data already fetched on the server. mutations and queries are each optional on dehydratedState. Queries not yet in the cache are built from the dehydrated snapshot; queries that already exist are only updated when the dehydrated data is newer than what's already cached. Newly built queries have their fetchStatus reset to 'idle' so they don't hydrate stuck in a fetching state. If a dehydrated query still had an in-flight promise, it is resumed via query.fetch() (reusing that promise as initialPromise) rather than re-invoking queryFn.

Parameters

client

QueryClient

The client whose cache is restored into.

dehydratedState

Partial<DehydratedState>

The dehydrated state, e.g. produced by dehydrate on the server.

dehydratedState properties

Built from DehydratedState. See the type above for what it changes.

options?

HydrateOptions

defaultOptions merged into every restored query and mutation (on top of the client's defaultOptions.hydrate), and deserializeData to reverse serializeData.

options properties

Property	Type	Description
defaultOptions?	object	Options applied to the queries and mutations restored from the dehydrated state.
defaultOptions.deserializeData?	TransformerFn	Transforms a query's data after it is read from the dehydrated state, reversing serializeData.
defaultOptions.mutations?	MutationOptions<unknown, Error, unknown, unknown>	Default options merged into every mutation restored from the dehydrated state.
defaultOptions.queries?	QueryOptions<unknown, Error, unknown, readonly unknown[], never>	Default options merged into every query restored from the dehydrated state.

Returns

void

Example

// dehydratedState was produced by `dehydrate` on the server
// and sent to the client, e.g. embedded in server-rendered markup.
const queryClient = new QueryClient()

hydrate(queryClient, dehydratedState)