Remove enum overhead

packages/firestore/src/api/user_data_converter.ts

@@ -126,7 +126,7 @@ export class ParsedUpdateData {
  * for determining which error conditions apply during parsing and providing
  * better error messages.
  */
-enum UserDataSource {
+const enum UserDataSource {
   Set,
   Update,
   MergeSet,

packages/firestore/src/core/event_manager.ts

@@ -51,7 +51,7 @@ export class EventManager implements SyncEngineListener {
     q.canonicalId()
   );
 
-  private onlineState: OnlineState = 'Unknown';
+  private onlineState = OnlineState.Unknown;
 
   private snapshotsInSyncListeners: Set<Observer<void>> = new Set();
 
@@ -209,7 +209,7 @@ export class QueryListener {
 
   private snap: ViewSnapshot | null = null;
 
-  private onlineState: OnlineState = 'Unknown';
+  private onlineState = OnlineState.Unknown;
 
   constructor(
     readonly query: Query,
@@ -300,7 +300,7 @@ export class QueryListener {
 
     // NOTE: We consider OnlineState.Unknown as online (it should become Offline
     // or Online if we wait long enough).
-    const maybeOnline = onlineState !== 'Offline';
+    const maybeOnline = onlineState !== OnlineState.Offline;
     // Don't raise the event if we're online, aren't synced yet (checked
     // above) and are waiting for a sync.
     if (this.options.waitForSyncWhenOnline && maybeOnline) {
@@ -312,7 +312,7 @@ export class QueryListener {
     }
 
     // Raise data from cache if we have any documents or we are offline
-    return !snap.docs.isEmpty() || onlineState === 'Offline';
+    return !snap.docs.isEmpty() || onlineState === OnlineState.Offline;
   }
 
   private shouldRaiseEvent(snap: ViewSnapshot): boolean {

packages/firestore/src/core/query.ts

@@ -30,7 +30,7 @@ import { Code, FirestoreError } from '../util/error';
 import { isNullOrUndefined } from '../util/types';
 import { Target } from './target';
 
-export enum LimitType {
+export const enum LimitType {
   First = 'F',
   Last = 'L'
 }

packages/firestore/src/core/sync_engine.ts

@@ -167,7 +167,7 @@ export class SyncEngine implements RemoteSyncer, SharedClientStateSyncer {
   // startup. In the interim, a client should only be considered primary if
   // `isPrimary` is true.
   private isPrimary: undefined | boolean = undefined;
-  private onlineState: OnlineState = 'Unknown';
+  private onlineState = OnlineState.Unknown;
 
   constructor(
     private localStore: LocalStore,
@@ -253,7 +253,7 @@ export class SyncEngine implements RemoteSyncer, SharedClientStateSyncer {
     const viewDocChanges = view.computeDocChanges(queryResult.documents);
     const synthesizedTargetChange = TargetChange.createSynthesizedTargetChangeForCurrentChange(
       targetId,
-      current && this.onlineState !== 'Offline'
+      current && this.onlineState !== OnlineState.Offline
     );
     const viewChange = view.applyChanges(
       viewDocChanges,

packages/firestore/src/core/target_id_generator.ts

@@ -20,7 +20,7 @@ import { TargetId } from './types';
 
 const RESERVED_BITS = 1;
 
-enum GeneratorIds {
+const enum GeneratorIds {
   QueryCache = 0, // The target IDs for user-issued queries are even (end in 0).
   SyncEngine = 1 // The target IDs for limbo detection are odd (end in 1).
 }

packages/firestore/src/core/types.ts

@@ -38,32 +38,36 @@ export type MutationBatchState = 'pending' | 'acknowledged' | 'rejected';
  * primarily used by the View / EventManager code to change their behavior while
  * offline (e.g. get() calls shouldn't wait for data from the server and
  * snapshot events should set metadata.isFromCache=true).
+ * 
+ * The string values should not be changed since they are persisted in
+ * WebStorage.
  */
-export type OnlineState =
+export const enum OnlineState {
   /**
    * The Firestore client is in an unknown online state. This means the client
    * is either not actively trying to establish a connection or it is currently
    * trying to establish a connection, but it has not succeeded or failed yet.
    * Higher-level components should not operate in offline mode.
    */
-  | 'Unknown'
+  Unknown = 'Unknown',
 
   /**
    * The client is connected and the connections are healthy. This state is
    * reached after a successful connection and there has been at least one
    * successful message received from the backends.
    */
-  | 'Online'
+  Online = 'Online',
 
   /**
    * The client is either trying to establish a connection but failing, or it
    * has been explicitly marked offline via a call to disableNetwork().
    * Higher-level components should operate in offline mode.
    */
-  | 'Offline';
+  Offline = 'Offline'
+}
 
 /** The source of an online state event. */
-export enum OnlineStateSource {
+export const enum OnlineStateSource {
   RemoteStore,
   SharedClientState
 }

packages/firestore/src/core/view.ts

@@ -336,7 +336,7 @@ export class View {
    * ViewChange if the view's syncState changes as a result.
    */
   applyOnlineStateChange(onlineState: OnlineState): ViewChange {
-    if (this.current && onlineState === 'Offline') {
+    if (this.current && onlineState === OnlineState.Offline) {
       // If we're offline, set `current` to false and then call applyChanges()
       // to refresh our syncState and generate a ViewChange as appropriate. We
       // are guaranteed to get a new TargetChange that sets `current` back to

packages/firestore/src/core/view_snapshot.ts

@@ -24,7 +24,7 @@ import { SortedMap } from '../util/sorted_map';
 import { DocumentKeySet } from '../model/collections';
 import { Query } from './query';
 
-export enum ChangeType {
+export const enum ChangeType {
   Added,
   Removed,
   Modified,
@@ -36,7 +36,7 @@ export interface DocumentViewChange {
   doc: Document;
 }
 
-export enum SyncState {
+export const enum SyncState {
   Local,
   Synced
 }

packages/firestore/src/local/target_data.ts

@@ -21,7 +21,7 @@ import { ListenSequenceNumber, TargetId } from '../core/types';
 import { ByteString } from '../util/byte_string';
 
 /** An enumeration of the different purposes we have for targets. */
-export enum TargetPurpose {
+export const enum TargetPurpose {
   /** A regular, normal query target. */
   Listen,
 

packages/firestore/src/model/field_value.ts

@@ -48,7 +48,7 @@ export interface JsonObject<T> {
   [name: string]: T;
 }
 
-export enum TypeOrder {
+export const enum TypeOrder {
   // This order is defined by the backend.
   NullValue = 0,
   BooleanValue = 1,
@@ -63,7 +63,7 @@ export enum TypeOrder {
 }
 
 /** Defines the return value for pending server timestamps. */
-export enum ServerTimestampBehavior {
+export const enum ServerTimestampBehavior {
   Default,
   Estimate,
   Previous

packages/firestore/src/model/mutation.ts

@@ -117,7 +117,7 @@ export class MutationResult {
   ) {}
 }
 
-export enum MutationType {
+export const enum MutationType {
   Set,
   Patch,
   Transform,

packages/firestore/src/remote/online_state_tracker.ts

@@ -50,7 +50,7 @@ const ONLINE_STATE_TIMEOUT_MS = 10 * 1000;
  */
 export class OnlineStateTracker {
   /** The current OnlineState. */
-  private state: OnlineState = 'Unknown';
+  private state = OnlineState.Unknown;
 
   /**
    * A count of consecutive failures to open the stream. If it reaches the
@@ -87,7 +87,7 @@ export class OnlineStateTracker {
    */
   handleWatchStreamStart(): void {
     if (this.watchStreamFailures === 0) {
-      this.setAndBroadcast('Unknown');
+      this.setAndBroadcast(OnlineState.Unknown);
 
       assert(
         this.onlineStateTimer === null,
@@ -99,14 +99,14 @@ export class OnlineStateTracker {
         () => {
           this.onlineStateTimer = null;
           assert(
-            this.state === 'Unknown',
+            this.state === OnlineState.Unknown,
             'Timer should be canceled if we transitioned to a different state.'
           );
           this.logClientOfflineWarningIfNecessary(
             `Backend didn't respond within ${ONLINE_STATE_TIMEOUT_MS / 1000} ` +
               `seconds.`
           );
-          this.setAndBroadcast('Offline');
+          this.setAndBroadcast(OnlineState.Offline);
 
           // NOTE: handleWatchStreamFailure() will continue to increment
           // watchStreamFailures even though we are already marked Offline,
@@ -125,8 +125,8 @@ export class OnlineStateTracker {
    * actually transition to the 'Offline' state.
    */
   handleWatchStreamFailure(error: FirestoreError): void {
-    if (this.state === 'Online') {
-      this.setAndBroadcast('Unknown');
+    if (this.state === OnlineState.Online) {
+      this.setAndBroadcast(OnlineState.Unknown);
 
       // To get to OnlineState.Online, set() must have been called which would
       // have reset our heuristics.
@@ -142,7 +142,7 @@ export class OnlineStateTracker {
             `times. Most recent error: ${error.toString()}`
         );
 
-        this.setAndBroadcast('Offline');
+        this.setAndBroadcast(OnlineState.Offline);
       }
     }
   }
@@ -158,7 +158,7 @@ export class OnlineStateTracker {
     this.clearOnlineStateTimer();
     this.watchStreamFailures = 0;
 
-    if (newState === 'Online') {
+    if (newState === OnlineState.Online) {
       // We've connected to watch at least once. Don't warn the developer
       // about being offline going forward.
       this.shouldWarnClientIsOffline = false;

packages/firestore/src/remote/persistent_stream.ts

@@ -63,7 +63,7 @@ export interface WriteRequest extends api.WriteRequest {
  *               stop() called or
  *               idle timer expired
  */
-enum PersistentStreamState {
+const enum PersistentStreamState {
   /**
    * The streaming RPC is not yet running and there's no error condition.
    * Calling start() will start the stream immediately without backoff.

packages/firestore/src/remote/remote_store.ts

@@ -191,7 +191,7 @@ export class RemoteStore implements TargetMetadataProvider {
       if (this.shouldStartWatchStream()) {
         this.startWatchStream();
       } else {
-        this.onlineStateTracker.set('Unknown');
+        this.onlineStateTracker.set(OnlineState.Unknown);
       }
 
       // This will start the write stream if necessary.
@@ -208,7 +208,7 @@ export class RemoteStore implements TargetMetadataProvider {
     await this.disableNetworkInternal();
 
     // Set the OnlineState to Offline so get()s return from cache, etc.
-    this.onlineStateTracker.set('Offline');
+    this.onlineStateTracker.set(OnlineState.Offline);
   }
 
   private async disableNetworkInternal(): Promise<void> {
@@ -234,7 +234,7 @@ export class RemoteStore implements TargetMetadataProvider {
 
     // Set the OnlineState to Unknown (rather than Offline) to avoid potentially
     // triggering spurious listener events with cached data, etc.
-    this.onlineStateTracker.set('Unknown');
+    this.onlineStateTracker.set(OnlineState.Unknown);
   }
 
   /**
@@ -279,7 +279,7 @@ export class RemoteStore implements TargetMetadataProvider {
         // Revert to OnlineState.Unknown if the watch stream is not open and we
         // have no listeners, since without any listens to send we cannot
         // confirm if the stream is healthy and upgrade to OnlineState.Online.
-        this.onlineStateTracker.set('Unknown');
+        this.onlineStateTracker.set(OnlineState.Unknown);
       }
     }
   }
@@ -371,7 +371,7 @@ export class RemoteStore implements TargetMetadataProvider {
       // No need to restart watch stream because there are no active targets.
       // The online state is set to unknown because there is no active attempt
       // at establishing a connection
-      this.onlineStateTracker.set('Unknown');
+      this.onlineStateTracker.set(OnlineState.Unknown);
     }
   }
 
@@ -380,7 +380,7 @@ export class RemoteStore implements TargetMetadataProvider {
     snapshotVersion: SnapshotVersion
   ): Promise<void> {
     // Mark the client as online since we got a message from the server
-    this.onlineStateTracker.set('Online');
+    this.onlineStateTracker.set(OnlineState.Online);
 
     if (
       watchChange instanceof WatchTargetChange &&
@@ -708,7 +708,7 @@ export class RemoteStore implements TargetMetadataProvider {
   private async restartNetwork(): Promise<void> {
     this.networkEnabled = false;
     await this.disableNetworkInternal();
-    this.onlineStateTracker.set('Unknown');
+    this.onlineStateTracker.set(OnlineState.Unknown);
     await this.enableNetwork();
   }
 
@@ -732,7 +732,7 @@ export class RemoteStore implements TargetMetadataProvider {
       await this.enableNetwork();
     } else if (!isPrimary) {
       await this.disableNetworkInternal();
-      this.onlineStateTracker.set('Unknown');
+      this.onlineStateTracker.set(OnlineState.Unknown);
     }
   }
 }

packages/firestore/src/remote/rpc_error.ts

@@ -27,7 +27,7 @@ import * as log from '../util/log';
  *
  * Important! The names of these identifiers matter because the string forms
  * are used for reverse lookups from the webchannel stream. Do NOT change the
- * names of these identifiers.
+ * names of these identifiers or change this into a const enum.
  */
 enum RpcCode {
   OK = 0,

packages/firestore/src/remote/watch_change.ts

@@ -74,7 +74,7 @@ export class ExistenceFilterChange {
   ) {}
 }
 
-export enum WatchTargetChangeState {
+export const enum WatchTargetChangeState {
   NoChange,
   Added,
   Removed,

packages/firestore/src/util/async_queue.ts

@@ -31,7 +31,7 @@ type TimerHandle = any;
  *
  * The string values are used when encoding these timer IDs in JSON spec tests.
  */
-export enum TimerId {
+export const enum TimerId {
   /** All can be used with runDelayedOperationsEarly() to run all timers. */
   All = 'all',
 

packages/firestore/src/util/log.ts

@@ -21,7 +21,7 @@ import { PlatformSupport } from '../platform/platform';
 
 const logClient = new Logger('@firebase/firestore');
 
-export enum LogLevel {
+export const enum LogLevel {
   DEBUG,
   ERROR,
   SILENT