In an e-commerce application, you want to fetch product details and customer reviews concurrently, and only update the UI when both pieces of data are available. Which RxJS operator should you use?
- combineLatest
- forkJoin
- mergeMap
- zip
To fetch data concurrently and update the UI when both are available, you should use the forkJoin operator, which waits for all observables to complete and then emits their last values as an array.
How can you dynamically add or remove form controls in an Angular form?
- Use *ngFor Directive
- Use Angular Material Form
- Use FormGroup API
- Use Reactive Forms Module
To dynamically add or remove form controls in an Angular form, you can use the FormGroup API. It allows you to add, remove, or manipulate form controls within a FormGroup dynamically based on user interactions or other criteria.
Reactive forms in Angular are also known as _____ forms.
- Data-driven forms
- Dynamic forms
- Model-driven forms
- Template forms
Reactive forms in Angular are also known as Model-driven forms, as they focus on creating the model and then binding it to the UI elements.
In a directive, the ________ decorator is used to get a reference to the host element.
- @Directive
- @HostBinding
- @HostListener
- @Injectable
In a directive, the @HostBinding decorator is used to get a reference to the host element, allowing you to access and modify its properties.
A directive that changes the appearance or behavior of a DOM element is known as a(n) _____ directive.
- attribute
- component
- decorator
- structural
A directive that changes the appearance or behavior of a DOM element is known as an attribute directive in Angular.
Which operator can be used to automatically unsubscribe from an observable when a component is destroyed?
- "map" operator
- "subscribe" operator
- "takeUntil" operator
- "tap" operator
The "takeUntil" operator is commonly used to automatically unsubscribe from an observable when a component is destroyed. It takes an observable that emits when the component is destroyed, ensuring that the original observable is unsubscribed.
When testing Angular services, you can replace a real service with a _____ to simulate service behavior.
- component
- mock
- pipe
- spy
When testing Angular services, you can replace a real service with a mock to simulate service behavior and control the service's responses for testing purposes.
Angular provides the _____ function to define a sequence of animation steps.
- animate()
- bootstrap()
- ngIf
- subscribe()
Angular provides the animate() function to define a sequence of animation steps. This function is commonly used for creating animations in Angular.
The [style.color] syntax in an Angular template is an example of _____ binding.
- Event
- Interpolation
- Property
- Two-way
The [style.color] syntax is an example of Property binding in Angular. It binds an element property (style.color) to a component property.
You are building an Angular application with a complex form. You want to create an E2E test using Protractor to ensure that the form validation works correctly and that the user can submit the form. What steps would you need to include in your test?
- Simulate user interaction
- Submit the form
- Test input validation
- Verify the response from the server
When creating an E2E test for form validation in Protractor, you should test input validation, including various valid and invalid inputs. You also need to simulate user interaction (e.g., entering data), submit the form, and finally verify the response from the server to ensure the form functions correctly.
Which type of Angular directive is responsible for manipulating the structure of the DOM?
- Attribute Directives
- Component Directives
- Pipe Directives
- Structural Directives
Structural directives are responsible for manipulating the structure of the DOM. They change the layout of the view by adding or removing elements from the DOM based on certain conditions or logic.
A cold observable starts emitting values only when it has at least one subscriber.
- delayed
- hot
- multicasting
- synchronous
A cold observable starts emitting values only when it has at least one subscriber.