use hasCachedResults instead of resumeToken

Author: milaGGL

packages/firestore/src/core/event_manager.ts

@@ -308,7 +308,7 @@ export class QueryListener {
         snap.fromCache,
         snap.syncStateChanged,
         /* excludesMetadataChanges= */ true,
-        snap.resumeToken
+        snap.hasCachedResults
       );
     }
     let raisedEvent = false;
@@ -376,7 +376,7 @@ export class QueryListener {
     // or we are offline.
     return (
       !snap.docs.isEmpty() ||
-      snap.resumeToken.approximateByteSize() > 0 ||
+      snap.hasCachedResults ||
       onlineState === OnlineState.Offline
     );
   }
@@ -412,7 +412,7 @@ export class QueryListener {
       snap.docs,
       snap.mutatedKeys,
       snap.fromCache,
-      snap.resumeToken
+      snap.hasCachedResults
     );
     this.raisedInitialEvent = true;
     this.queryObserver.next(snap);

packages/firestore/src/core/view.ts

@@ -26,7 +26,6 @@ import { DocumentKey } from '../model/document_key';
 import { DocumentSet } from '../model/document_set';
 import { TargetChange } from '../remote/remote_event';
 import { debugAssert, fail } from '../util/assert';
-import { ByteString } from '../util/byte_string';
 
 import { LimitType, newQueryComparator, Query, queryMatches } from './query';
 import { OnlineState } from './types';
@@ -73,7 +72,7 @@ export interface ViewChange {
  */
 export class View {
   private syncState: SyncState | null = null;
-  private resumeToken: ByteString | null = null;
+  private hasCachedResults: boolean = false;
   /**
    * A flag whether the view is current with the backend. A view is considered
    * current after it has seen the current flag from the backend and did not
@@ -322,7 +321,8 @@ export class View {
         newSyncState === SyncState.Local,
         syncStateChanged,
         /* excludesMetadataChanges= */ false,
-        targetChange?.resumeToken ?? ByteString.EMPTY_BYTE_STRING
+        targetChange !== undefined &&
+          targetChange.resumeToken.approximateByteSize() > 0
       );
       return {
         snapshot: snap,
@@ -472,7 +472,7 @@ export class View {
       this.documentSet,
       this.mutatedKeys,
       this.syncState === SyncState.Local,
-      this.resumeToken ?? ByteString.EMPTY_BYTE_STRING
+      this.hasCachedResults
     );
   }
 }

packages/firestore/src/core/view_snapshot.ts

@@ -20,7 +20,6 @@ import { Document } from '../model/document';
 import { DocumentKey } from '../model/document_key';
 import { DocumentSet } from '../model/document_set';
 import { fail } from '../util/assert';
-import { ByteString } from '../util/byte_string';
 import { SortedMap } from '../util/sorted_map';
 
 import { Query, queryEquals } from './query';
@@ -148,7 +147,7 @@ export class ViewSnapshot {
     readonly fromCache: boolean,
     readonly syncStateChanged: boolean,
     readonly excludesMetadataChanges: boolean,
-    readonly resumeToken: ByteString
+    readonly hasCachedResults: boolean
   ) {}
 
   /** Returns a view snapshot as if all documents in the snapshot were added. */
@@ -157,7 +156,7 @@ export class ViewSnapshot {
     documents: DocumentSet,
     mutatedKeys: DocumentKeySet,
     fromCache: boolean,
-    resumeToken: ByteString
+    hasCachedResults: boolean
   ): ViewSnapshot {
     const changes: DocumentViewChange[] = [];
     documents.forEach(doc => {
@@ -173,7 +172,7 @@ export class ViewSnapshot {
       fromCache,
       /* syncStateChanged= */ true,
       /* excludesMetadataChanges= */ false,
-      resumeToken
+      hasCachedResults
     );
   }
 

packages/firestore/test/util/api_helpers.ts

@@ -155,7 +155,7 @@ export function querySnapshot(
     fromCache,
     syncStateChanged,
     false,
-    resumeToken ?? ByteString.EMPTY_BYTE_STRING
+    resumeToken !== undefined && resumeToken.approximateByteSize() > 0
   );
   const db = firestore();
   return new QuerySnapshot(