Compile time asserts

packages/firestore/src/api/database.ts

@@ -1429,7 +1429,7 @@ export class QueryDocumentSnapshot extends DocumentSnapshot
       typeof data === 'object',
       'Document in a QueryDocumentSnapshot should exist'
     );
-    return data as firestore.DocumentData;
+    return data;
   }
 }
 

packages/firestore/src/api/user_data_converter.ts

@@ -504,7 +504,7 @@ export class UserDataConverter {
       context.fieldTransforms.length === 0,
       'Field transforms should have been disallowed.'
     );
-    return parsed!;
+    return parsed;
   }
 
   /** Sends data through this.preConverter, handling any thrown errors. */

packages/firestore/src/core/query.ts

@@ -523,13 +523,12 @@ export class FieldFilter extends Filter {
           value instanceof ArrayValue,
           'Comparing on key with IN, but filter value not an ArrayValue'
         );
-        assert(
-          (value as ArrayValue).internalValue.every(elem => {
+        assert(value.internalValue.every(elem => {
             return elem instanceof RefValue;
           }),
           'Comparing on key with IN, but an array value was not a RefValue'
         );
-        return new KeyFieldInFilter(field, value as ArrayValue);
+        return new KeyFieldInFilter(field, value);
       } else {
         assert(
           value instanceof RefValue,
@@ -539,7 +538,7 @@ export class FieldFilter extends Filter {
           op !== Operator.ARRAY_CONTAINS && op !== Operator.ARRAY_CONTAINS_ANY,
           `'${op.toString()}' queries don't make sense on document keys.`
         );
-        return new KeyFieldFilter(field, op, value as RefValue);
+        return new KeyFieldFilter(field, op, value);
       }
     } else if (value.isEqual(NullValue.INSTANCE)) {
       if (op !== Operator.EQUAL) {
@@ -564,13 +563,13 @@ export class FieldFilter extends Filter {
         value instanceof ArrayValue,
         'IN filter has invalid value: ' + value.toString()
       );
-      return new InFilter(field, value as ArrayValue);
+      return new InFilter(field, value);
     } else if (op === Operator.ARRAY_CONTAINS_ANY) {
       assert(
         value instanceof ArrayValue,
         'ARRAY_CONTAINS_ANY filter has invalid value: ' + value.toString()
       );
-      return new ArrayContainsAnyFilter(field, value as ArrayValue);
+      return new ArrayContainsAnyFilter(field, value);
     } else {
       return new FieldFilter(field, op, value);
     }
@@ -765,7 +764,7 @@ export class Bound {
           'Bound has a non-key value where the key path is being used.'
         );
         comparison = DocumentKey.comparator(
-          (component as RefValue).key,
+          component.key,
           doc.key
         );
       } else {
@@ -774,7 +773,7 @@ export class Bound {
           docValue !== null,
           'Field should exist since document matched the orderBy already.'
         );
-        comparison = component.compareTo(docValue!);
+        comparison = component.compareTo(docValue);
       }
       if (orderByComponent.dir === Direction.DESCENDING) {
         comparison = comparison * -1;

packages/firestore/src/core/sync_engine.ts

@@ -980,7 +980,7 @@ export class SyncEngine implements RemoteSyncer, SharedClientStateSyncer {
           assert(!!queryView, `No query view found for ${query}`);
 
           const viewChange = await this.synchronizeViewAndComputeSnapshot(
-            queryView!
+            queryView
           );
           if (viewChange.snapshot) {
             newViewSnapshots.push(viewChange.snapshot);
@@ -995,7 +995,7 @@ export class SyncEngine implements RemoteSyncer, SharedClientStateSyncer {
         // allocate the target in LocalStore and initialize a new View.
         const target = await this.localStore.getTarget(targetId);
         assert(!!target, `Target for id ${targetId} not found`);
-        targetData = await this.localStore.allocateTarget(target!);
+        targetData = await this.localStore.allocateTarget(target);
         await this.initializeViewAndComputeSnapshot(
           this.synthesizeTargetToQuery(target!),
           targetId,
@@ -1097,9 +1097,9 @@ export class SyncEngine implements RemoteSyncer, SharedClientStateSyncer {
       );
       const target = await this.localStore.getTarget(targetId);
       assert(!!target, `Query data for active target ${targetId} not found`);
-      const targetData = await this.localStore.allocateTarget(target!);
+      const targetData = await this.localStore.allocateTarget(target);
       await this.initializeViewAndComputeSnapshot(
-        this.synthesizeTargetToQuery(target!),
+        this.synthesizeTargetToQuery(target),
         targetData.targetId,
         /*current=*/ false
       );
@@ -1151,7 +1151,7 @@ export class SyncEngine implements RemoteSyncer, SharedClientStateSyncer {
       for (const query of queries) {
         const queryView = this.queryViewsByQuery.get(query);
         assert(!!queryView, `No query view found for ${query}`);
-        keySet = keySet.unionWith(queryView!.view.syncedDocuments);
+        keySet = keySet.unionWith(queryView.view.syncedDocuments);
       }
       return keySet;
     }

packages/firestore/src/local/indexeddb_mutation_queue.ts

@@ -352,7 +352,7 @@ export class IndexedDbMutationQueue implements MutationQueue {
               mutation.userId === this.userId,
               `Unexpected user '${mutation.userId}' for mutation batch ${batchId}`
             );
-            results.push(this.serializer.fromDbMutationBatch(mutation!));
+            results.push(this.serializer.fromDbMutationBatch(mutation));
           });
       })
       .next(() => results);
@@ -483,7 +483,7 @@ export class IndexedDbMutationQueue implements MutationQueue {
               mutation.userId === this.userId,
               `Unexpected user '${mutation.userId}' for mutation batch ${batchId}`
             );
-            results.push(this.serializer.fromDbMutationBatch(mutation!));
+            results.push(this.serializer.fromDbMutationBatch(mutation));
           })
       );
     });

packages/firestore/src/local/indexeddb_persistence.ts

@@ -949,7 +949,7 @@ export class IndexedDbPersistence implements Persistence {
           typeof this.document.addEventListener === 'function',
         "Expected 'document.addEventListener' to be a function"
       );
-      this.document!.removeEventListener(
+      this.document.removeEventListener(
         'visibilitychange',
         this.documentVisibilityHandler
       );

packages/firestore/src/local/indexeddb_target_cache.ts

@@ -421,7 +421,7 @@ function retrieveMetadata(
   );
   return globalStore.get(DbTargetGlobal.key).next(metadata => {
     assert(metadata !== null, 'Missing metadata row.');
-    return metadata!;
+    return metadata;
   });
 }
 

packages/firestore/src/local/local_store.ts

@@ -432,8 +432,8 @@ export class LocalStore {
           .lookupMutationBatch(txn, batchId)
           .next((batch: MutationBatch | null) => {
             assert(batch !== null, 'Attempt to reject nonexistent batch!');
-            affectedKeys = batch!.keys();
-            return this.mutationQueue.removeMutationBatch(txn, batch!);
+            affectedKeys = batch.keys();
+            return this.mutationQueue.removeMutationBatch(txn, batch);
           })
           .next(() => {
             return this.mutationQueue.performConsistencyCheck(txn);
@@ -746,8 +746,8 @@ export class LocalStore {
         );
 
         // Advance the last limbo free snapshot version
-        const lastLimboFreeSnapshotVersion = targetData!.snapshotVersion;
-        const updatedTargetData = targetData!.withLastLimboFreeSnapshotVersion(
+        const lastLimboFreeSnapshotVersion = targetData.snapshotVersion;
+        const updatedTargetData = targetData.withLastLimboFreeSnapshotVersion(
           lastLimboFreeSnapshotVersion
         );
         this.targetDataByTarget = this.targetDataByTarget.insert(

packages/firestore/src/local/memory_mutation_queue.ts

@@ -158,7 +158,7 @@ export class MemoryMutationQueue implements MutationQueue {
     const mutationBatch = this.findMutationBatch(batchId);
     assert(mutationBatch != null, 'Failed to find local mutation batch.');
     return PersistencePromise.resolve<DocumentKeySet | null>(
-      mutationBatch!.keys()
+      mutationBatch.keys()
     );
   }
 

packages/firestore/src/local/remote_document_change_buffer.ts

@@ -82,7 +82,7 @@ export abstract class RemoteDocumentChangeBuffer {
       this._readTime !== undefined,
       'Read time is not set. All removeEntry() calls must include a readTime if `trackRemovals` is used.'
     );
-    return this._readTime!;
+    return this._readTime;
   }
 
   /**

packages/firestore/src/local/shared_client_state.ts

@@ -963,7 +963,7 @@ export class WebStorageSharedClientState implements SharedClientState {
   ): RemoteClientState | null {
     const clientId = this.fromWebStorageClientStateKey(key);
     assert(clientId !== null, `Cannot parse client state key '${key}'`);
-    return RemoteClientState.fromWebStorageEntry(clientId!, value);
+    return RemoteClientState.fromWebStorageEntry(clientId, value);
   }
 
   /**
@@ -977,8 +977,8 @@ export class WebStorageSharedClientState implements SharedClientState {
     const match = this.mutationBatchKeyRe.exec(key);
     assert(match !== null, `Cannot parse mutation batch key '${key}'`);
 
-    const batchId = Number(match![1]);
-    const userId = match![2] !== undefined ? match![2] : null;
+    const batchId = Number(match[1]);
+    const userId = match[2] !== undefined ? match[2] : null;
     return MutationMetadata.fromWebStorageEntry(
       new User(userId),
       batchId,
@@ -997,7 +997,7 @@ export class WebStorageSharedClientState implements SharedClientState {
     const match = this.queryTargetKeyRe.exec(key);
     assert(match !== null, `Cannot parse query target key '${key}'`);
 
-    const targetId = Number(match![1]);
+    const targetId = Number(match[1]);
     return QueryTargetMetadata.fromWebStorageEntry(targetId, value);
   }
 

packages/firestore/src/local/simple_query_engine.ts

@@ -49,7 +49,7 @@ export class SimpleQueryEngine implements QueryEngine {
 
     // TODO: Once LocalDocumentsView provides a getCollectionDocuments()
     // method, we should call that here and then filter the results.
-    return this.localDocumentsView!.getDocumentsMatchingQuery(
+    return this.localDocumentsView.getDocumentsMatchingQuery(
       transaction,
       query,
       SnapshotVersion.MIN

packages/firestore/src/model/mutation.ts

@@ -654,12 +654,11 @@ export class TransformMutation extends Mutation {
       maybeDoc instanceof Document,
       'Unknown MaybeDocument type ' + maybeDoc
     );
-    const doc = maybeDoc! as Document;
     assert(
-      doc.key.isEqual(this.key),
+        maybeDoc.key.isEqual(this.key),
       'Can only transform a document with the same key'
     );
-    return doc;
+    return maybeDoc;
   }
 
   /**

packages/firestore/src/model/transform_operation.ts

@@ -219,7 +219,7 @@ export class NumericIncrementTransformOperation implements TransformOperation {
       transformResult !== null,
       "Didn't receive transformResult for NUMERIC_ADD transform"
     );
-    return transformResult!;
+    return transformResult;
   }
 
   /**

packages/firestore/src/remote/datastore.ts

@@ -115,7 +115,7 @@ export class Datastore {
       keys.forEach(key => {
         const doc = docs.get(key);
         assert(!!doc, 'Missing entity in write response for ' + key);
-        result.push(doc!);
+        result.push(doc);
       });
       return result;
     });

packages/firestore/src/remote/persistent_stream.ts

@@ -698,7 +698,7 @@ export class PersistentWriteStream extends PersistentStream<
       !!responseProto.streamToken,
       'Got a write response without a stream token'
     );
-    this.lastStreamToken = responseProto.streamToken!;
+    this.lastStreamToken = responseProto.streamToken;
 
     if (!this.handshakeComplete_) {
       // The first response is always the handshake response

packages/firestore/src/remote/serializer.ts

@@ -257,9 +257,9 @@ export class JsonProtoSerializer {
     let nanos = 0;
     const fraction = ISO_REG_EXP.exec(utc);
     assert(!!fraction, 'invalid timestamp: ' + utc);
-    if (fraction![1]) {
+    if (fraction[1]) {
       // Pad the fraction out to 9 digits (nanos).
-      let nanoStr = fraction![1];
+      let nanoStr = fraction[1];
       nanoStr = (nanoStr + '000000000').substr(0, 9);
       nanos = Number(nanoStr);
     }
@@ -595,11 +595,11 @@ export class JsonProtoSerializer {
       !!doc.found,
       'Tried to deserialize a found document from a missing document.'
     );
-    assertPresent(doc.found!.name, 'doc.found.name');
-    assertPresent(doc.found!.updateTime, 'doc.found.updateTime');
-    const key = this.fromName(doc.found!.name!);
-    const version = this.fromVersion(doc.found!.updateTime!);
-    return new Document(key, version, {}, undefined, doc.found!, v =>
+    assertPresent(doc.found.name, 'doc.found.name');
+    assertPresent(doc.found.updateTime, 'doc.found.updateTime');
+    const key = this.fromName(doc.found.name!);
+    const version = this.fromVersion(doc.found.updateTime!);
+    return new Document(key, version, {}, undefined, doc.found, v =>
       this.fromValue(v)
     );
   }
@@ -613,8 +613,8 @@ export class JsonProtoSerializer {
       !!result.readTime,
       'Tried to deserialize a missing document without a read time.'
     );
-    const key = this.fromName(result.missing!);
-    const version = this.fromVersion(result.readTime!);
+    const key = this.fromName(result.missing);
+    const version = this.fromVersion(result.readTime);
     return new NoDocument(key, version);
   }
 
@@ -950,7 +950,7 @@ export class JsonProtoSerializer {
         commitTime !== undefined,
         'Received a write result without a commit time'
       );
-      return protos.map(proto => this.fromWriteResult(proto, commitTime!));
+      return protos.map(proto => this.fromWriteResult(proto, commitTime));
     } else {
       return [];
     }

packages/firestore/src/remote/stream_bridge.ts

@@ -66,22 +66,22 @@ export class StreamBridge<I, O> implements Stream<I, O> {
       this.wrappedOnOpen !== undefined,
       'Cannot call onOpen because no callback was set'
     );
-    this.wrappedOnOpen!();
+    this.wrappedOnOpen();
   }
 
   callOnClose(err?: FirestoreError): void {
     assert(
       this.wrappedOnClose !== undefined,
       'Cannot call onClose because no callback was set'
     );
-    this.wrappedOnClose!(err);
+    this.wrappedOnClose(err);
   }
 
   callOnMessage(msg: O): void {
     assert(
       this.wrappedOnMessage !== undefined,
       'Cannot call onMessage because no callback was set'
     );
-    this.wrappedOnMessage!(msg);
+    this.wrappedOnMessage(msg);
   }
 }

packages/firestore/src/util/assert.ts

@@ -43,7 +43,7 @@ export function fail(failure: string): never {
  * Fails if the given assertion condition is false, throwing an Error with the
  * given message if it did.
  */
-export function assert(assertion: boolean, message: string): void {
+export function assert(assertion: boolean, message: string): asserts assertion {
   if (!assertion) {
     fail(message);
   }

packages/firestore/test/unit/local/local_store.test.ts

@@ -300,9 +300,9 @@ class LocalStoreTester {
         this.lastChanges !== null,
         'Called toReturnChanged() without prior after()'
       );
-      expect(this.lastChanges!.size).to.equal(docs.length, 'number of changes');
+      expect(this.lastChanges.size).to.equal(docs.length, 'number of changes');
       for (const doc of docs) {
-        const returned = this.lastChanges!.get(doc.key);
+        const returned = this.lastChanges.get(doc.key);
         expectEqual(
           doc,
           returned,
@@ -322,12 +322,12 @@ class LocalStoreTester {
         this.lastChanges !== null,
         'Called toReturnRemoved() without prior after()'
       );
-      expect(this.lastChanges!.size).to.equal(
+      expect(this.lastChanges.size).to.equal(
         keyStrings.length,
         'Number of actual changes mismatched number of expected changes'
       );
       for (const keyString of keyStrings) {
-        const returned = this.lastChanges!.get(key(keyString));
+        const returned = this.lastChanges.get(key(keyString));
         expect(returned).to.be.an.instanceof(NoDocument);
       }
       this.lastChanges = null;

packages/firestore/test/util/helpers.ts

@@ -571,7 +571,7 @@ export function documentSet(...args: unknown[]): DocumentSet {
   }
   for (const doc of args) {
     assert(doc instanceof Document, 'Bad argument, expected Document: ' + doc);
-    docSet = docSet.add(doc as Document);
+    docSet = docSet.add(doc);
   }
   return docSet;
 }