In Angular, when using a hot observable, what happens to the data emissions when there are no subscribers?
- Data emissions are buffered and sent to the next subscriber when they subscribe.
- Data emissions are cached and sent to the first subscriber who subscribes.
- Data emissions are lost if there are no subscribers.
- Data emissions are sent to a separate storage location for later retrieval.
When using a hot observable in Angular, data emissions are lost if there are no subscribers. They are not cached or buffered for future subscribers.
When using Jasmine for unit testing in Angular, what function is used to create a group of related tests?
- afterEach()
- beforeAll()
- describe()
- it()
In Jasmine, the describe() function is used to create a group of related tests, which helps organize and structure your test suite.
You are building a complex form that needs to enable or disable sections of the form based on user input. Which type of form would be more suitable to implement this, and why?
- Both are equally suitable
- None of the above
- Reactive forms
- Template-driven forms
To enable or disable sections of a form based on user input, Reactive forms would be more suitable because they provide greater programmatic control and flexibility.
To create a dynamic form in Angular, developers often use the ____ class to programmatically add form controls.
- FormArray
- FormControl
- FormGroup
- NgForm
To create a dynamic form in Angular, developers often use the FormArray class to programmatically add form controls. A FormArray is used when you need to manage a list of form controls.
How can a parent component communicate with a child component without using @Input or @Output?
- Use BehaviorSubject and Renderer2
- Use Dependency Injection and ElementRef
- Use EventEmitter and ViewChildren
- Use ViewChild and ElementRef
A parent component can communicate with a child component without @Input or @Output by using ViewChild and ElementRef to access the child's properties and methods directly.
When using Jasmine and Karma for testing, how can you ensure that a specific test or suite of tests is executed while others are ignored?
- Apply a custom test filter
- Enable verbose logging
- Set a test timeout
- Use the "xit" or "fdescribe" keywords
In Jasmine and Karma testing, you can ensure that a specific test or suite of tests is executed while others are ignored by using the "xit" (exclude it) or "fdescribe" (focus describe) keywords.
Which lifecycle hook is best suited to react to changes in a component's input properties?
- ngAfterViewInit
- ngDoCheck
- ngOnChanges
- ngOnInit
The ngOnChanges lifecycle hook is best suited to react to changes in a component's input properties. It provides information about the changes to input properties.
What does the async pipe do in an Angular template?
- Handles routing
- Renders HTML
- Subscribes to an Observable
- Transforms data
The async pipe in an Angular template subscribes to an Observable and automatically updates the view with the most recent data emitted by the Observable. It simplifies working with asynchronous data in templates.
When testing a directive that modifies the DOM, what should you consider to ensure that the tests are not flaky?
- Avoid testing such directives as they are inherently flaky
- Check for DOM changes in a loop until they are detected consistently
- Use a stubbed version of the directive to isolate DOM changes
- Use asynchronous timers to delay test execution until the DOM changes
To prevent flaky tests when testing a directive that modifies the DOM, use a stubbed version of the directive to isolate DOM changes and ensure reliable testing.
In Angular, the replaceUrl property of the _____ object can be used to navigate while replacing the current URL in the browser's history.
- ActivatedRouteSnapshot
- NavigationExtras
- Router
- RouterStateSnapshot
In Angular, the replaceUrl property of the RouterStateSnapshot object can be used to navigate while replacing the current URL in the browser's history. It allows for URL manipulation.
In an Angular application, you want to ensure that data for a specific route is fetched and ready before the route is activated. How would you achieve this?
- Configure route preloading strategies to ensure data is available before route activation.
- Fetch data in the route component's constructor and use a loading spinner until it's available.
- Implement a global data service to fetch data, and check data availability in the route's lifecycle hooks.
- Use route resolvers to fetch and resolve the data before activating the route.
To ensure that data for a specific route is fetched and ready before the route is activated, you should use route resolvers. Resolvers fetch and resolve the data before activating the route, ensuring the data is available when the route component is initialized.
How does Angular Universal improve the perceived performance of an application?
- It enhances routing performance
- It improves code quality
- It reduces the bundle size
- It speeds up the initial rendering of a page
Angular Universal improves the perceived performance of an application by speeding up the initial rendering of a page on the server side.