upstream-tanstack-query/docs/framework/lit/reference/classes/QueriesObserver.md

id, title

id	title
QueriesObserver	QueriesObserver

Defined in: packages/query-core/src/queriesObserver.ts:56

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>(
   client,
   queries,
options?): QueriesObserver<TCombinedResult>;

Defined in: packages/query-core/src/queriesObserver.ts:70

Parameters

client

QueryClient

queries

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

options?

QueriesObserverOptions<TCombinedResult>

Returns

QueriesObserver<TCombinedResult>

Overrides

Subscribable<QueriesObserverListener>.constructor

Properties

listeners

protected listeners: Set<QueriesObserverListener>;

Defined in: packages/query-core/src/subscribable.ts:2

Inherited from

Subscribable.listeners

Methods

destroy()

destroy(): void;

Defined in: packages/query-core/src/queriesObserver.ts:106

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:210

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[]

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:227

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[]>[]

---

getOptimisticResult()

getOptimisticResult(queries, combine): [QueryObserverResult[], (r?) => TCombinedResult, () => QueryObserverResult[]];

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

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>[]

combine

CombineFn<TCombinedResult> | undefined

Returns

[QueryObserverResult[], (r?) => TCombinedResult, () => QueryObserverResult[]]

---

getQueries()

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

Defined in: packages/query-core/src/queriesObserver.ts:218

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[]>[]

---

hasListeners()

hasListeners(): boolean;

Defined in: packages/query-core/src/subscribable.ts:19

Returns

boolean

Inherited from

Subscribable.hasListeners

---

onSubscribe()

protected onSubscribe(): void;

Defined in: packages/query-core/src/queriesObserver.ts:86

Returns

void

Overrides

Subscribable.onSubscribe

---

onUnsubscribe()

protected onUnsubscribe(): void;

Defined in: packages/query-core/src/queriesObserver.ts:96

Returns

void

Overrides

Subscribable.onUnsubscribe

---

setQueries()

setQueries(queries, options?): void;

Defined in: packages/query-core/src/queriesObserver.ts:127

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>[]

options?

QueriesObserverOptions<TCombinedResult>

Returns

void

Example

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

---

subscribe()

subscribe(listener): () => void;

Defined in: packages/query-core/src/subscribable.ts:8

Parameters

listener

QueriesObserverListener

Returns

(): void;

Returns

void

Inherited from

Subscribable.subscribe