feat(angular-query): added observable support

packages/angular-query-experimental/package.json

@@ -54,12 +54,14 @@
     "@angular/platform-browser": "^17.0.8",
     "@angular/platform-browser-dynamic": "^17.0.8",
     "ng-packagr": "^17.0.3",
+    "rxjs": "^7.8.1",
     "typescript": "5.2.2",
     "zone.js": "^0.14.2"
   },
   "peerDependencies": {
     "@angular/core": "^17",
-    "@angular/common": "^17"
+    "@angular/common": "^17",
+    "rxjs": "^7"
   },
   "module": "build/fesm2022/tanstack-angular-query-experimental.mjs",
   "types": "build/index.d.ts",

packages/angular-query-experimental/src/__tests__/inject-query.test-d.ts

@@ -1,8 +1,16 @@
 import { describe, expectTypeOf } from 'vitest'
+import { interval, map, take } from 'rxjs'
 import { injectQuery } from '../inject-query'
 import { simpleFetcher } from './test-utils'
 import type { Signal } from '@angular/core'
 
+function simpleObservable() {
+  return interval(1000).pipe(
+    map((_, i) => `Some data ${i}`),
+    take(5),
+  )
+}
+
 describe('Discriminated union return type', () => {
   test('data should be possibly undefined by default', () => {
     const query = injectQuery(() => ({
@@ -56,4 +64,24 @@ describe('Discriminated union return type', () => {
       expectTypeOf(query.error).toEqualTypeOf<Signal<Error>>()
     }
   })
+
+  test('data should be infered from a passed in observable', () => {
+    const query = injectQuery(() => ({
+      queryKey: ['key'],
+      query$: () => simpleObservable(),
+    }))
+
+    expectTypeOf(query.data).toEqualTypeOf<Signal<string | undefined>>()
+  })
+
+  test('data should still be defined when query is successful', () => {
+    const query = injectQuery(() => ({
+      queryKey: ['key'],
+      query$: () => simpleObservable(),
+    }))
+
+    if (query.isSuccess()) {
+      expectTypeOf(query.data).toEqualTypeOf<Signal<string>>()
+    }
+  })
 })

packages/angular-query-experimental/src/__tests__/inject-query.test.ts

@@ -2,6 +2,7 @@ import { computed, signal } from '@angular/core'
 import { TestBed, fakeAsync, flush, tick } from '@angular/core/testing'
 import { QueryClient } from '@tanstack/query-core'
 import { expect, vi } from 'vitest'
+import { Subject } from 'rxjs'
 import { injectQuery } from '../inject-query'
 import { provideAngularQuery } from '../providers'
 import {
@@ -215,4 +216,51 @@ describe('injectQuery', () => {
 
     expect(query.status()).toBe('error')
   }))
+
+  test('should allow an observable to be passed as queryFn', fakeAsync(() => {
+    const subject$ = new Subject<string>()
+    const query = TestBed.runInInjectionContext(() => {
+      return injectQuery(() => ({
+        queryKey: ['key14'],
+        query$: () => subject$.asObservable(),
+      }))
+    })
+
+    expect(query.status()).toBe('pending')
+
+    flush()
+
+    subject$.next('Some data')
+
+    flush()
+    expect(query.status()).toBe('success')
+    expect(query.data()).toBe('Some data')
+  }))
+
+  test('should allow to error when the stream is emitting after the first time it emits', fakeAsync(() => {
+    const subject$ = new Subject<string>()
+    const query = TestBed.runInInjectionContext(() => {
+      return injectQuery(() => ({
+        queryKey: ['key14'],
+        query$: () => subject$.asObservable(),
+      }))
+    })
+
+    expect(query.status()).toBe('pending')
+
+    flush()
+
+    subject$.next('Some data')
+
+    flush()
+    expect(query.status()).toBe('success')
+    expect(query.data()).toBe('Some data')
+
+    subject$.error(new Error('Some error'))
+
+    flush()
+
+    expect(query.status()).toBe('error')
+    expect(query.error()).toMatchObject({ message: 'Some error' })
+  }))
 })

packages/angular-query-experimental/src/create-base-query.ts

@@ -7,9 +7,28 @@ import {
   signal,
 } from '@angular/core'
 import { notifyManager } from '@tanstack/query-core'
+import {
+  EMPTY,
+  Subject,
+  catchError,
+  fromEvent,
+  lastValueFrom,
+  shareReplay,
+  skip,
+  switchMap,
+  take,
+  takeUntil,
+} from 'rxjs'
+import { takeUntilDestroyed } from '@angular/core/rxjs-interop'
 import { signalProxy } from './signal-proxy'
-import type { QueryClient, QueryKey, QueryObserver } from '@tanstack/query-core'
+import type {
+  QueryClient,
+  QueryFunctionContext,
+  QueryKey,
+  QueryObserver,
+} from '@tanstack/query-core'
 import type { CreateBaseQueryOptions, CreateBaseQueryResult } from './types'
+import type { Subscription } from 'rxjs'
 
 /**
  * Base implementation for `injectQuery` and `injectInfiniteQuery`.
@@ -20,6 +39,7 @@ export function createBaseQuery<
   TData,
   TQueryData,
   TQueryKey extends QueryKey,
+  TPageParam = never,
 >(
   options: (
     client: QueryClient,
@@ -28,24 +48,100 @@ export function createBaseQuery<
     TError,
     TData,
     TQueryData,
-    TQueryKey
+    TQueryKey,
+    TPageParam
   >,
   Observer: typeof QueryObserver,
   queryClient: QueryClient,
 ): CreateBaseQueryResult<TData, TError> {
   assertInInjectionContext(createBaseQuery)
   const destroyRef = inject(DestroyRef)
 
+  /**
+   * Subscription to the query$ observable.
+   */
+  let subscription: Subscription | undefined
+
   /**
    * Signal that has the default options from query client applied
    * computed() is used so signals can be inserted into the options
    * making it reactive. Wrapping options in a function ensures embedded expressions
    * are preserved and can keep being applied after signal changes
    */
   const defaultedOptionsSignal = computed(() => {
-    const defaultedOptions = queryClient.defaultQueryOptions(
-      options(queryClient),
-    )
+    const { query$, ...opts } = options(queryClient)
+
+    // If there is a subscription, unsubscribe from it this is to prevent
+    // multiple subscriptions on the same computed type
+    if (subscription) subscription.unsubscribe()
+
+    /**
+     * Subscribe to the query$ observable and set the query data
+     * when the observable emits a value. This creates a promise
+     * on the queryFn and on each new emit it will update the client
+     * side.
+     */
+    if (query$) {
+      const trigger$ = new Subject<
+        QueryFunctionContext<TQueryKey, TPageParam>
+      >()
+
+      const obs$ = trigger$.pipe(
+        switchMap((context) =>
+          query$(context).pipe(
+            takeUntil(
+              // If the signal is aborted, abort the observable
+              fromEvent(context.signal, 'abort'),
+            ),
+          ),
+        ),
+        shareReplay(1),
+        takeUntilDestroyed(destroyRef),
+      )
+
+      subscription = obs$
+        .pipe(
+          skip(1),
+          catchError((error: Error) => {
+            const query = queryClient
+              .getQueryCache()
+              .find({ queryKey: opts.queryKey })
+            if (query) {
+              const { state } = query
+              // Mimic the dispatch code on the error case found in the query-core package
+              query.setState({
+                ...state,
+                error,
+                errorUpdateCount: state.errorUpdateCount + 1,
+                errorUpdatedAt: Date.now(),
+                fetchFailureCount: state.fetchFailureCount + 1,
+                fetchFailureReason: error,
+                fetchStatus: 'idle',
+                status: 'error',
+              })
+            }
+            return EMPTY
+          }),
+        )
+        .subscribe({
+          next: (value) =>
+            queryClient.setQueryData<TQueryFnData>(opts.queryKey, value),
+        })
+
+      const queryFn = (
+        context: QueryFunctionContext<TQueryKey, TPageParam>,
+      ) => {
+        // Trigger the observable with the new context.
+        const promise = lastValueFrom(obs$.pipe(take(1)))
+        trigger$.next(context)
+        return promise
+      }
+
+      opts.queryFn = queryFn
+    }
+
+    const defaultedOptions = queryClient.defaultQueryOptions(opts)
+
     defaultedOptions._optimisticResults = 'optimistic'
     return defaultedOptions
   })

packages/angular-query-experimental/src/types.ts

@@ -1,4 +1,5 @@
 import type { Signal } from '@angular/core'
+import type { Observable } from 'rxjs'
 
 import type {
   DefaultError,
@@ -8,6 +9,7 @@ import type {
   MutateFunction,
   MutationObserverOptions,
   MutationObserverResult,
+  QueryFunctionContext,
   QueryKey,
   QueryObserverOptions,
   QueryObserverResult,
@@ -21,10 +23,22 @@ export interface CreateBaseQueryOptions<
   TData = TQueryFnData,
   TQueryData = TQueryFnData,
   TQueryKey extends QueryKey = QueryKey,
+  TPageParam = never,
 > extends WithRequired<
-    QueryObserverOptions<TQueryFnData, TError, TData, TQueryData, TQueryKey>,
+    QueryObserverOptions<
+      TQueryFnData,
+      TError,
+      TData,
+      TQueryData,
+      TQueryKey,
+      TPageParam
+    >,
     'queryKey'
-  > {}
+  > {
+  query$?: (
+    context: QueryFunctionContext<TQueryKey, TPageParam>,
+  ) => Observable<TQueryFnData>
+}
 
 type CreateStatusBasedQueryResult<
   TStatus extends QueryObserverResult['status'],