fix(docs-infra): do not break when cookies are disabled in the browser (#35557)

Whenever cookies are disabled in the browser, `window.localStorage` is
not avaialable to the app (i.e. even trying to access
`window.localStorage` throws an error).

To avoid breaking the app, we use a no-op `Storage` implementation if
`window.localStorage` is not available.

(This is similar to #33829, but for `localStorage` instead of
`sessionStorage`.)

Fixes #35555

PR Close #35557

aio/src/app/layout/notification/notification.component.spec.ts

@@ -111,6 +111,22 @@ describe('NotificationComponent', () => {
     expect(getItemSpy).toHaveBeenCalledWith('aio-notification/survey-january-2018');
     expect(component.showNotification).toBe('hide');
   });
+
+  it('should not break when cookies are disabled in the browser', () => {
+    configTestingModule();
+
+    // Simulate `window.localStorage` being inaccessible, when cookies are disabled.
+    const mockWindow: MockWindow = TestBed.inject(WindowToken);
+    Object.defineProperty(mockWindow, 'localStorage', {
+      get() { throw new Error('The operation is insecure'); },
+    });
+
+    expect(() => createComponent()).not.toThrow();
+    expect(component.showNotification).toBe('show');
+
+    component.dismiss();
+    expect(component.showNotification).toBe('hide');
+  });
 });
 
 @Component({

aio/src/app/layout/notification/notification.component.ts

@@ -20,7 +20,7 @@ const LOCAL_STORAGE_NAMESPACE = 'aio-notification/';
   ]
 })
 export class NotificationComponent implements OnInit {
-  private get localStorage() { return this.window.localStorage; }
+  private storage: Storage;
 
   @Input() dismissOnContentClick: boolean;
   @Input() notificationId: string;
@@ -31,12 +31,27 @@ export class NotificationComponent implements OnInit {
   showNotification: 'show'|'hide';
 
   constructor(
-    @Inject(WindowToken) private window: Window,
+    @Inject(WindowToken) window: Window,
     @Inject(CurrentDateToken) private currentDate: Date
-  ) {}
+  ) {
+    try {
+      this.storage = window.localStorage;
+    } catch {
+      // When cookies are disabled in the browser, even trying to access
+      // `window.localStorage` throws an error. Use a no-op storage.
+      this.storage = {
+        length: 0,
+        clear: () => undefined,
+        getItem: () => null,
+        key: () => null,
+        removeItem: () => undefined,
+        setItem: () => undefined
+      };
+    }
+  }
 
   ngOnInit() {
-    const previouslyHidden = this.localStorage.getItem(LOCAL_STORAGE_NAMESPACE + this.notificationId) === 'hide';
+    const previouslyHidden = this.storage.getItem(LOCAL_STORAGE_NAMESPACE + this.notificationId) === 'hide';
     const expired = this.currentDate > new Date(this.expirationDate);
     this.showNotification = previouslyHidden || expired ? 'hide' : 'show';
   }
@@ -48,7 +63,7 @@ export class NotificationComponent implements OnInit {
   }
 
   dismiss() {
-    this.localStorage.setItem(LOCAL_STORAGE_NAMESPACE + this.notificationId, 'hide');
+    this.storage.setItem(LOCAL_STORAGE_NAMESPACE + this.notificationId, 'hide');
     this.showNotification = 'hide';
     this.dismissed.next();
   }