QueriesObserver

Defined in: packages/query-core/src/queriesObserver.ts:64

A QueriesObserver watches an array of queries at once, exposing them as a single array of QueryObserverResults (or, when a combine option is given, as a combined value derived from that array). It manages one internal QueryObserver per query, and is the primitive that framework adapters (e.g. useQueries) build their hooks on top of.

Example#

const observer = new QueriesObserver(queryClient, [
  { queryKey: ['post', 1], queryFn: fetchPost },
  { queryKey: ['post', 2], queryFn: fetchPost },
])

const unsubscribe = observer.subscribe((result) => {
  console.log(result)
})

Extends#

• Subscribable<QueriesObserverListener>

Type Parameters#

TCombinedResult#

TCombinedResult = QueryObserverResult[]

Constructors#

Constructor#

new QueriesObserver<TCombinedResult = QueryObserverResult[]>(
   client: QueryClient,
   queries: QueryObserverOptions<any, any, any, any, any, never>[],
   options?: QueriesObserverOptions<TCombinedResult>
): QueriesObserver<TCombinedResult>;

Defined in: packages/query-core/src/queriesObserver.ts:78

Parameters#

client#

QueryClient

queries#

QueryObserverOptions<any, any, any, any, any, never>[]

options?#

QueriesObserverOptions<TCombinedResult>

Returns#

QueriesObserver<TCombinedResult>

Overrides#

Subscribable<QueriesObserverListener>.constructor

Methods#

destroy()#

destroy(): void;

Defined in: packages/query-core/src/queriesObserver.ts:114

Stops observing all queries: clears all listeners and destroys every underlying QueryObserver this observer manages.

Returns#

void

getCurrentResult()#

getCurrentResult(): QueryObserverResult[];

Defined in: packages/query-core/src/queriesObserver.ts:219

Returns the most recently computed array of QueryObserverResults, one per observed query, in the same order as the queries passed to the constructor or setQueries.

Returns#

QueryObserverResult[]

The current results.

Example#

const results = observer.getCurrentResult()
const data = results.map((result) => result.data)

getObservers()#

getObservers(): QueryObserver<unknown, Error, unknown, unknown, readonly unknown[]>[];

Defined in: packages/query-core/src/queriesObserver.ts:238

Returns the underlying QueryObserver instances this observer manages, in the same order as the queries passed to the constructor or setQueries.

Returns#

QueryObserver<unknown, Error, unknown, unknown, readonly unknown[]>[]

The managed query observers.

getOptimisticResult()#

getOptimisticResult(queries: QueryObserverOptions<unknown, Error, unknown, unknown, readonly unknown[], never>[], combine: CombineFn<TCombinedResult> | undefined): [rawResult: QueryObserverResult[], combineResult: (r?: QueryObserverResult[]) => TCombinedResult, trackResult: () => QueryObserverResult[]];

Defined in: packages/query-core/src/queriesObserver.ts:253

The QueriesObserver counterpart of QueryObserver#getOptimisticResult — computes the result for the given (already-defaulted) queries right now, synchronously. Called by framework adapters (e.g. useQueries) ahead of subscribing, returning a tuple of the raw per-query results, a function to compute the combined result from them, and a function to wrap the results for property-access tracking.

Parameters#

queries#

QueryObserverOptions<unknown, Error, unknown, unknown, readonly unknown[], never>[]

The defaulted options of the queries to compute the result for.

combine#

CombineFn<TCombinedResult> | undefined

The combine function used by the returned combineResult, if any.

Returns#

[rawResult: QueryObserverResult[], combineResult: (r?: QueryObserverResult[]) => TCombinedResult, trackResult: () => QueryObserverResult[]]

A tuple of the per-query results, a function that computes the combined result, and a function that returns the results wrapped for property-access tracking.

getQueries()#

getQueries(): Query<unknown, Error, unknown, readonly unknown[]>[];

Defined in: packages/query-core/src/queriesObserver.ts:228

Returns the underlying Query instances currently being observed, in the same order as the queries passed to the constructor or setQueries.

Returns#

Query<unknown, Error, unknown, readonly unknown[]>[]

The observed queries.

hasListeners()#

hasListeners(): boolean;

Defined in: packages/query-core/src/subscribable.ts:43

Returns true while at least one listener is registered, false once they have all unsubscribed.

Returns#

boolean

true if at least one listener is registered.

Inherited from#

Subscribable.hasListeners

setQueries()#

setQueries(queries: QueryObserverOptions<unknown, Error, unknown, unknown, readonly unknown[], never>[], options?: QueriesObserverOptions<TCombinedResult>): void;

Defined in: packages/query-core/src/queriesObserver.ts:136

Replaces the set of queries being observed. Existing QueryObservers are reused for queries that match an already-observed query hash; observers for queries that are no longer present are destroyed, and new observers are created and subscribed to for newly added queries.

Parameters#

queries#

QueryObserverOptions<unknown, Error, unknown, unknown, readonly unknown[], never>[]

The options of the queries to observe.

options?#

QueriesObserverOptions<TCombinedResult>

Replaces the observer's options, e.g. its combine function.

Returns#

void

Example#

observer.setQueries([
  { queryKey: ['post', 1], queryFn: fetchPost },
  { queryKey: ['post', 3], queryFn: fetchPost },
])

subscribe()#

subscribe(listener: QueriesObserverListener): () => void;

Defined in: packages/query-core/src/subscribable.ts:28

Registers a listener to be called on every update this object notifies about. Returns a function that removes the listener again — call it to stop listening. The base class never drops a listener on its own, though some subclasses clear all of theirs in destroy().

Parameters#

listener#

QueriesObserverListener

Called on each update, with whatever the subclass passes to its subscribers.

Returns#

A function that removes the listener.

() => void

Example#

const unsubscribe = subscribable.subscribe(() => {
  // react to the update
})

unsubscribe()

Inherited from#

Subscribable.subscribe