test(preview): add tests for createObserveDocument

packages/sanity/src/core/preview/__test__/createObserveDocument.test.ts

@@ -0,0 +1,113 @@
+import {describe, expect, it, jest} from '@jest/globals'
+import {createClient, type WelcomeEvent} from '@sanity/client'
+import {firstValueFrom, of, skip, Subject} from 'rxjs'
+import {take} from 'rxjs/operators'
+
+import {createObserveDocument, type ListenerMutationEventLike} from '../createObserveDocument'
+
+describe(createObserveDocument.name, () => {
+  it('fetches the current version of the document when receiving welcome event', async () => {
+    const mockedClient = createClient({
+      projectId: 'abc',
+      dataset: 'production',
+      apiVersion: '2024-08-27',
+      useCdn: false,
+    })
+
+    jest
+      .spyOn(mockedClient.observable, 'fetch')
+      .mockImplementation(() => of([{_id: 'foo', fetched: true}]) as any)
+    jest.spyOn(mockedClient, 'withConfig').mockImplementation(() => mockedClient)
+
+    const mutationChannel = new Subject<WelcomeEvent | ListenerMutationEventLike>()
+
+    const observeDocument = createObserveDocument({
+      mutationChannel,
+      client: mockedClient,
+    })
+
+    const initial = firstValueFrom(observeDocument('foo').pipe(take(1)))
+
+    mutationChannel.next({type: 'welcome'})
+
+    expect(await initial).toEqual({_id: 'foo', fetched: true})
+  })
+
+  it('emits undefined if the document does not exist', async () => {
+    const mockedClient = createClient({
+      projectId: 'abc',
+      dataset: 'production',
+      apiVersion: '2024-08-27',
+      useCdn: false,
+    })
+
+    jest.spyOn(mockedClient.observable, 'fetch').mockImplementation(() => of([]) as any)
+    jest.spyOn(mockedClient, 'withConfig').mockImplementation(() => mockedClient)
+
+    const mutationChannel = new Subject<WelcomeEvent | ListenerMutationEventLike>()
+
+    const observeDocument = createObserveDocument({
+      mutationChannel,
+      client: mockedClient,
+    })
+
+    const initial = firstValueFrom(observeDocument('foo').pipe(take(1)))
+
+    mutationChannel.next({type: 'welcome'})
+
+    expect(await initial).toEqual(undefined)
+  })
+
+  it('applies a mendoza patch when received over the listener', async () => {
+    const mockedClient = createClient({
+      projectId: 'abc',
+      dataset: 'production',
+      apiVersion: '2024-08-27',
+      useCdn: false,
+    })
+
+    jest.spyOn(mockedClient.observable, 'fetch').mockImplementation(
+      () =>
+        of([
+          {
+            _createdAt: '2024-08-27T09:01:42Z',
+            _id: '1c32390c',
+            _rev: 'a8403810-81f7-49e6-8860-e52cb9111431',
+            _type: 'foo',
+            _updatedAt: '2024-08-27T09:03:38Z',
+            name: 'foo',
+          },
+        ]) as any,
+    )
+    jest.spyOn(mockedClient, 'withConfig').mockImplementation(() => mockedClient)
+
+    const mutationChannel = new Subject<WelcomeEvent | ListenerMutationEventLike>()
+
+    const observeDocument = createObserveDocument({
+      mutationChannel,
+      client: mockedClient,
+    })
+
+    const final = firstValueFrom(observeDocument('1c32390c').pipe(skip(1), take(1)))
+
+    mutationChannel.next({type: 'welcome'})
+    mutationChannel.next({
+      type: 'mutation',
+      documentId: '1c32390c',
+      previousRev: 'a8403810-81f7-49e6-8860-e52cb9111431',
+      resultRev: 'b3e7ebce-2bdd-4ab7-9056-b525773bd17a',
+      effects: {
+        apply: [11, 3, 23, 0, 18, 22, '8', 23, 19, 20, 15, 17, 'foos', 'name'],
+      },
+    })
+
+    expect(await final).toEqual({
+      _createdAt: '2024-08-27T09:01:42Z',
+      _id: '1c32390c',
+      _rev: 'b3e7ebce-2bdd-4ab7-9056-b525773bd17a',
+      _type: 'foo',
+      _updatedAt: '2024-08-27T09:03:38Z',
+      name: 'foos',
+    })
+  })
+})

packages/sanity/src/core/preview/createObserveDocument.ts

@@ -9,12 +9,21 @@ import {type ApiConfig} from './types'
 import {applyMutationEventEffects} from './utils/applyMendozaPatch'
 import {debounceCollect} from './utils/debounceCollect'
 
+export type ListenerMutationEventLike = Pick<
+  MutationEvent,
+  'type' | 'documentId' | 'previousRev' | 'resultRev'
+> & {
+  effects: {
+    apply: unknown[]
+  }
+}
+
 export function createObserveDocument({
   mutationChannel,
   client,
 }: {
   client: SanityClient
-  mutationChannel: Observable<WelcomeEvent | MutationEvent>
+  mutationChannel: Observable<WelcomeEvent | ListenerMutationEventLike>
 }) {
   const getBatchFetcher = memoize(
     function getBatchFetcher(apiConfig: {dataset: string; projectId: string}) {
@@ -72,7 +81,7 @@ export function createObserveDocument({
   }
 }
 
-function applyMutationEvent(current: SanityDocument | undefined, event: MutationEvent) {
+function applyMutationEvent(current: SanityDocument | undefined, event: ListenerMutationEventLike) {
   if (event.previousRev !== current?._rev) {
     console.warn('Document out of sync, skipping mutation')
     return current