Change listeners

Author: sam-gc

packages-exp/auth-exp/src/core/auth/auth_impl.ts

@@ -17,8 +17,11 @@
 
 import { getApp } from '@firebase/app-exp';
 import { FirebaseApp } from '@firebase/app-types-exp';
+import {
+    CompleteFn, createSubscribe, ErrorFn, NextFn, Observer, Subscribe, Unsubscribe
+} from '@firebase/util';
 
-import { Auth, Config, Dependencies } from '../../model/auth';
+import { Auth, Config, Dependencies, NextOrObserver } from '../../model/auth';
 import { User } from '../../model/user';
 import { AuthErrorCode } from '../errors';
 import { Persistence } from '../persistence';
@@ -37,6 +40,13 @@ class AuthImpl implements Auth {
   currentUser: User | null = null;
   private operations = Promise.resolve();
   private persistenceManager?: PersistenceUserManager;
+  private authStateSubscription = new Subscription<User>(this);
+  private idTokenSubscription = new Subscription<User>(this);
+  private isInitialized = false;
+  
+  // Tracks the last notified UID for state change listeners to prevent
+  // repeated calls to the callbacks
+  private lastNotifiedUid: string|undefined = undefined;
 
   constructor(
     public readonly name: string,
@@ -57,6 +67,9 @@ class AuthImpl implements Auth {
       if (storedUser) {
         await this.directlySetCurrentUser(storedUser);
       }
+
+      this.isInitialized = true;
+      this._notifyStateListeners();
     });
   }
 
@@ -74,6 +87,47 @@ class AuthImpl implements Auth {
     });
   }
 
+  onAuthStateChanged(nextOrObserver: NextOrObserver<User>,
+    error?: ErrorFn,
+    completed?: CompleteFn): Unsubscribe {
+    return this.registerStateListener(this.authStateSubscription, nextOrObserver, error, completed);
+  }
+
+  onIdTokenChange(nextOrObserver: NextOrObserver<User>,
+    error?: ErrorFn,
+    completed?: CompleteFn): Unsubscribe {
+    return this.registerStateListener(this.idTokenSubscription, nextOrObserver, error, completed);
+  }
+
+  _notifyStateListeners(): void {
+    if (!this.isInitialized) {
+      return;
+    }
+
+    this.idTokenSubscription.next(this.currentUser);
+
+    if (this.lastNotifiedUid !== this.currentUser?.uid) {
+      this.lastNotifiedUid = this.currentUser?.uid;
+      this.authStateSubscription.next(this.currentUser);
+    }
+  }
+
+  private registerStateListener(subscription: Subscription<User>, nextOrObserver: NextOrObserver<User>,
+    error?: ErrorFn,
+    completed?: CompleteFn): Unsubscribe {
+    if (this.isInitialized) {
+      const cb = typeof nextOrObserver === 'function' ? nextOrObserver : nextOrObserver.next;
+      // The callback needs to be called asynchronously per the spec
+      Promise.resolve().then(() => cb(this.currentUser));
+    }
+    
+    if (typeof nextOrObserver === 'function') {
+      return subscription.addObserver(nextOrObserver, error, completed);
+    } else {
+      return subscription.addObserver(nextOrObserver);
+    }
+  }
+
   /**
    * Unprotected (from race conditions) method to set the current user. This
    * should only be called from within a queued callback. This is necessary
@@ -87,6 +141,8 @@ class AuthImpl implements Auth {
     } else {
       await this.assertedPersistence.removeCurrentUser();
     }
+
+    this._notifyStateListeners();
   }
 
   private queue(action: AsyncAction): Promise<void> {
@@ -120,3 +176,17 @@ export function initializeAuth(
 
   return new AuthImpl(app.name, config, hierarchy);
 }
+
+/** Helper class to wrap subscriber logic */
+class Subscription<T> {
+  private observer: Observer<T|null> | null = null;
+  readonly addObserver: Subscribe<T|null> = createSubscribe(
+    observer => this.observer = observer,
+  );
+
+  constructor(readonly auth: Auth) {}
+
+  get next(): NextFn<T|null> {
+    return assert(this.observer, this.auth.name).next;
+  }
+}

packages-exp/auth-exp/src/core/user/user_impl.ts

@@ -42,6 +42,7 @@ export class UserImpl implements User {
 
   uid: string;
   auth: Auth;
+  emailVerified = false;
 
   // Optional fields from UserInfo
   displayName: string | null;

packages-exp/auth-exp/src/model/auth.d.ts

@@ -15,12 +15,15 @@
  * limitations under the License.
  */
 
+import { CompleteFn, ErrorFn, NextFn, Observer, Unsubscribe } from '@firebase/util';
+
 import { Persistence } from '../core/persistence';
 import { User } from './user';
 
 export type AppName = string;
 export type ApiKey = string;
 export type AuthDomain = string;
+export type NextOrObserver<T> = NextFn<T|null> | Observer<T|null>;
 
 export interface Config {
   apiKey: ApiKey;
@@ -38,6 +41,8 @@ export interface Auth {
   setPersistence(persistence: Persistence): Promise<void>;
   updateCurrentUser(user: User | null): Promise<void>;
   signOut(): Promise<void>;
+  onAuthStateChanged(nextOrObserver: NextOrObserver<User>, error?: ErrorFn, completed?: CompleteFn): Unsubscribe;
+  onIdTokenChange(nextOrObserver: NextOrObserver<User>, error?: ErrorFn, completed?: CompleteFn): Unsubscribe;
 }
 
 export interface Dependencies {

packages-exp/auth-exp/src/model/user.d.ts

@@ -31,6 +31,7 @@ export interface UserInfo {
 export interface User extends UserInfo {
   providerId: ProviderId.FIREBASE;
   refreshToken: string;
+  emailVerified: boolean;
 
   getIdToken(forceRefresh?: boolean): Promise<string>;
   getIdTokenResult(forceRefresh?: boolean): Promise<IdTokenResult>;

packages-exp/auth-exp/test/mock_auth.ts

@@ -35,7 +35,9 @@ export const mockAuth: Auth = {
   currentUser: null,
   async setPersistence() {},
   async updateCurrentUser() {},
-  async signOut() {}
+  async signOut() {},
+  onAuthStateChanged() {return () => {}},
+  onIdTokenChange() { return () => {}},
 };
 
 export function testUser(uid: string, email?: string): User {