Review

Author: schmidt-sebastian

packages/firestore/src/local/local_store.ts

@@ -1054,9 +1054,10 @@ export function lookupMutationDocuments(
   localStore: LocalStore,
   batchId: BatchId
 ): Promise<MaybeDocumentMap | null> {
-  const localStoreImpl = debugCast(localStore, LocalStoreImpl);
-  const mutationQueueImpl = debugCast(
-    localStoreImpl.mutationQueue,
+  const [localStoreImpl, mutationQueueImpl] = debugCast(
+    localStore,
+    LocalStoreImpl,
+    (localStore as LocalStoreImpl).mutationQueue,
     IndexedDbMutationQueue // We only support IndexedDb in multi-tab mode.
   );
   return localStoreImpl.persistence.runTransaction(
@@ -1082,9 +1083,8 @@ export function removeCachedMutationBatchMetadata(
   localStore: LocalStore,
   batchId: BatchId
 ): void {
-  const localStoreImpl = debugCast(localStore, LocalStoreImpl);
   const mutationQueueImpl = debugCast(
-    localStoreImpl.mutationQueue,
+    debugCast(localStore, LocalStoreImpl).mutationQueue,
     IndexedDbMutationQueue // We only support IndexedDb in multi-tab mode.
   );
   mutationQueueImpl.removeCachedMutationKeys(batchId);
@@ -1094,9 +1094,8 @@ export function removeCachedMutationBatchMetadata(
 export function getCurrentlyActiveClients(
   localStore: LocalStore
 ): Promise<ClientId[]> {
-  const localStoreImpl = debugCast(localStore, LocalStoreImpl);
   const persistenceImpl = debugCast(
-    localStoreImpl.persistence,
+    debugCast(localStore, LocalStoreImpl).persistence,
     IndexedDbPersistence // We only support IndexedDb in multi-tab mode.
   );
   return persistenceImpl.getActiveClients();
@@ -1107,9 +1106,10 @@ export function getCachedTarget(
   localStore: LocalStore,
   targetId: TargetId
 ): Promise<Target | null> {
-  const localStoreImpl = debugCast(localStore, LocalStoreImpl);
-  const targetCacheImpl = debugCast(
-    localStoreImpl.targetCache,
+  const [localStoreImpl, targetCacheImpl] = debugCast(
+    localStore,
+    LocalStoreImpl,
+    (localStore as LocalStoreImpl).targetCache,
     IndexedDbTargetCache // We only support IndexedDb in multi-tab mode.
   );
   const cachedTargetData = localStoreImpl.targetDataByTarget.get(targetId);
@@ -1131,16 +1131,17 @@ export function getCachedTarget(
 /**
  * Returns the set of documents that have been updated since the last call.
  * If this is the first call, returns the set of changes since client
- * initialization. Further invocations will return document changes since
- * the point of rejection.
+ * initialization. Further invocations will return document that have changed
+ * since the prior call.
  */
 // PORTING NOTE: Multi-Tab only.
 export function getNewDocumentChanges(
   localStore: LocalStore
 ): Promise<MaybeDocumentMap> {
-  const localStoreImpl = debugCast(localStore, LocalStoreImpl);
-  const remoteDocumentCacheImpl = debugCast(
-    localStoreImpl.remoteDocuments,
+  const [localStoreImpl, remoteDocumentCacheImpl] = debugCast(
+    localStore,
+    LocalStoreImpl,
+    (localStore as LocalStoreImpl).remoteDocuments,
     IndexedDbRemoteDocumentCache // We only support IndexedDb in multi-tab mode.
   );
   return localStoreImpl.persistence
@@ -1157,8 +1158,8 @@ export function getNewDocumentChanges(
 }
 
 /**
- * Reads the newest document change from persistence and forwards the internal
- * synchronization marker so that calls to `getNewDocumentChanges()`
+ * Reads the newest document change from persistence and moves the internal
+ * synchronization marker forward so that calls to `getNewDocumentChanges()`
  * only return changes that happened after client initialization.
  */
 // PORTING NOTE: Multi-Tab only.

packages/firestore/src/util/assert.ts

@@ -72,17 +72,44 @@ export function debugAssert(
 }
 
 /**
- * Casts `obj` to `T`. In non-production builds, verifies that `obj` is an
- * instance of `T` before casting.
+ * Casts `obj1` to `S` and `obj2` to `T`. In non-production builds,
+ * verifies that `obj1` and `obj2` are instances of `S` and `T` before casting.
  */
-export function debugCast<T>(
+export function debugCast<S, T>(
+  obj1: object,
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  constructor1: { new (...args: any[]): S },
+  obj2: object,
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  constructor2: { new (...args: any[]): T }
+): [S, T] | never;
+/**
+ * Casts `obj` to `S`. In non-production builds, verifies that `obj` is an
+ * instance of `S` before casting.
+ */
+export function debugCast<S>(
   obj: object,
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  constructor: { new (...args: any[]): T }
-): T | never {
+  constructor: { new (...args: any[]): S }
+): S | never;
+export function debugCast<S, T>(
+  obj1: object,
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  constructor1: { new (...args: any[]): S },
+  obj2?: object,
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  constructor2?: { new (...args: any[]): T }
+): S | [S, T] | never {
+  debugAssert(
+    obj1 instanceof constructor1,
+    `Expected type '${constructor1.name}', but was '${obj1.constructor.name}'`
+  );
+  if (!obj2 || !constructor2) {
+    return obj1 as S;
+  }
   debugAssert(
-    obj instanceof constructor,
-    `Expected type '${constructor.name}', but was '${obj.constructor.name}'`
+    obj2 instanceof constructor2,
+    `Expected type '${constructor2.name}', but was '${obj2.constructor.name}'`
   );
-  return obj as T;
+  return [obj1 as S, obj2 as T];
 }