Make initializeAuth() idempotent

packages-exp/auth-exp/src/core/auth/initialize.test.ts

@@ -50,6 +50,7 @@ import {
 import { ClientPlatform, _getClientVersion } from '../util/version';
 import { initializeAuth } from './initialize';
 import { registerAuth } from './register';
+import { debugErrorMap, prodErrorMap } from '../errors';
 
 describe('core/auth/initialize', () => {
   let fakeApp: FirebaseApp;
@@ -127,7 +128,8 @@ describe('core/auth/initialize', () => {
     }
   }
 
-  const fakePopupRedirectResolver: PopupRedirectResolver = FakePopupRedirectResolver;
+  const fakePopupRedirectResolver: PopupRedirectResolver =
+    FakePopupRedirectResolver;
 
   before(() => {
     registerAuth(ClientPlatform.BROWSER);
@@ -203,15 +205,63 @@ describe('core/auth/initialize', () => {
       const auth = initializeAuth(fakeApp, {
         popupRedirectResolver: fakePopupRedirectResolver
       }) as AuthInternal;
-      await ((auth as unknown) as _FirebaseService)._delete();
+      await (auth as unknown as _FirebaseService)._delete();
       await auth._initializationPromise;
 
       expect(auth._isInitialized).to.be.false;
     });
 
-    it('should throw if called more than once', () => {
-      initializeAuth(fakeApp);
-      expect(() => initializeAuth(fakeApp)).to.throw();
+    it('should not throw if called again with same (no) params', () => {
+      const auth = initializeAuth(fakeApp);
+      expect(initializeAuth(fakeApp)).to.equal(auth);
+    });
+
+    it('should not throw if called again with same params', () => {
+      const auth = initializeAuth(fakeApp, {
+        errorMap: prodErrorMap,
+        persistence: fakeSessionPersistence,
+        popupRedirectResolver: fakePopupRedirectResolver
+      });
+      expect(
+        initializeAuth(fakeApp, {
+          errorMap: prodErrorMap,
+          persistence: fakeSessionPersistence,
+          popupRedirectResolver: fakePopupRedirectResolver
+        })
+      ).to.equal(auth);
+    });
+
+    it('should throw if called again with different params (popupRedirectResolver)', () => {
+      initializeAuth(fakeApp, {
+        popupRedirectResolver: fakePopupRedirectResolver
+      });
+      expect(() =>
+        initializeAuth(fakeApp, {
+          popupRedirectResolver: undefined
+        })
+      ).to.throw();
+    });
+
+    it('should throw if called again with different params (errorMap)', () => {
+      initializeAuth(fakeApp, {
+        errorMap: prodErrorMap
+      });
+      expect(() =>
+        initializeAuth(fakeApp, {
+          errorMap: debugErrorMap
+        })
+      ).to.throw();
+    });
+
+    it('should throw if called again with different params (persistence)', () => {
+      initializeAuth(fakeApp, {
+        persistence: [inMemoryPersistence, fakeSessionPersistence]
+      });
+      expect(() =>
+        initializeAuth(fakeApp, {
+          persistence: [fakeSessionPersistence, inMemoryPersistence]
+        })
+      ).to.throw();
     });
   });
 });

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

@@ -16,6 +16,7 @@
  */
 
 import { _getProvider, FirebaseApp } from '@firebase/app-exp';
+import { deepEqual } from '@firebase/util';
 import { Auth, Dependencies } from '../../model/public_types';
 
 import { AuthErrorCode } from '../errors';
@@ -54,7 +55,12 @@ export function initializeAuth(app: FirebaseApp, deps?: Dependencies): Auth {
 
   if (provider.isInitialized()) {
     const auth = provider.getImmediate() as AuthImpl;
-    _fail(auth, AuthErrorCode.ALREADY_INITIALIZED);
+    const initialOptions = provider.getOptions() as Dependencies;
+    if (deepEqual(initialOptions, deps ?? {})) {
+      return auth;
+    } else {
+      _fail(auth, AuthErrorCode.ALREADY_INITIALIZED);
+    }
   }
 
   const auth = provider.initialize({ options: deps }) as AuthImpl;
@@ -67,9 +73,8 @@ export function _initializeAuthInstance(
   deps?: Dependencies
 ): void {
   const persistence = deps?.persistence || [];
-  const hierarchy = (Array.isArray(persistence)
-    ? persistence
-    : [persistence]
+  const hierarchy = (
+    Array.isArray(persistence) ? persistence : [persistence]
   ).map<PersistenceInternal>(_getInstance);
   if (deps?.errorMap) {
     auth._updateErrorMap(deps.errorMap);

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

@@ -349,7 +349,10 @@ function _debugErrorMap(): ErrorMap<AuthErrorCode> {
     [AuthErrorCode.WEB_STORAGE_UNSUPPORTED]:
       'This browser is not supported or 3rd party cookies and data may be disabled.',
     [AuthErrorCode.ALREADY_INITIALIZED]:
-      'Auth can only be initialized once per app.'
+      'initializeAuth() has already been called with ' +
+      'different options. To avoid this error, call initializeAuth() with the ' +
+      'same options as when it was originally called, or call getAuth() to return the' +
+      ' already initialized instance.'
   };
 }