You are working on an autocomplete feature. As a user types into a search box, you want to delay the API call until the user has stopped typing for a specific duration. Which RxJS operator would you utilize?
- debounceTime
- mergeMap
- switchMap
- throttleTime
To achieve this behavior, you should use the debounceTime operator in RxJS. It allows you to wait for a specific duration of inactivity before emitting the latest value, which is ideal for scenarios like autocomplete.
You want to test a component that has a dependency on another service, but you don't want to test the service's actual behavior. How would you approach this in Angular tests?
- Create a mock service that provides controlled responses
- Mock the component instead of the service
- Use HttpClientTestingModule to mock HTTP service
- Use the actual service for realistic testing
To isolate the component's behavior for testing, you should create a mock service that provides controlled responses. This allows you to focus solely on testing the component's interactions with the service without invoking the actual service logic.
What is the primary purpose of Ahead-of-Time (AOT) Compilation in Angular?
- Easier debugging
- Enhanced developer experience
- Improved runtime performance
- Reduced code maintainability
The primary purpose of Ahead-of-Time (AOT) Compilation in Angular is improved runtime performance. AOT compiles Angular templates and components during the build process, resulting in faster rendering and smaller bundle sizes when compared to Just-in-Time (JIT) Compilation.
If you want to handle an Observable that emits multiple values over time but you're only interested in the latest value when another Observable emits, which operator would you use?
- combineLatest
- exhaustMap
- mergeMap
- switchMap
To handle an Observable that emits multiple values over time but only get the latest value when another Observable emits, you would use the combineLatest operator. It combines the latest values from multiple Observables whenever any of them emits a new value.
The mechanism that allows you to inject content from a parent component into a child component's view is known as ________.
- Propagation
- Data binding
- Content projection
- Component interaction
Content projection is the mechanism that enables you to inject content from a parent component into a child component's view. It is commonly used in frameworks like Angular to pass content from a parent component to specific slots in a child component. Options 1, 2, and 4 are not accurate descriptions of this mechanism.
What is the primary use of the HttpClient module in Angular?
- Handling form submissions
- Making HTTP requests to a server
- Managing component state
- Rendering UI components
The primary use of the HttpClient module in Angular is to make HTTP requests to a server. It provides a convenient way to interact with APIs and retrieve data from remote sources, such as RESTful services. HttpClient simplifies tasks like GET, POST, PUT, and DELETE requests and allows you to handle responses and errors effectively.
What's the primary use of the Renderer2 class in custom directives?
- Defining custom pipes.
- Handling HTTP requests.
- Managing form controls.
- Manipulating the DOM directly.
The primary use of the Renderer2 class in custom directives is to manipulate the DOM directly. It provides a safer and more platform-agnostic way to interact with the DOM, ensuring that changes are rendered consistently across different platforms and environments. It's essential for making dynamic changes to the DOM within Angular applications.
Which object is responsible for tracking the value and validation status of an individual form control in reactive forms?
- FormArray
- FormControl
- FormField
- FormGroup
In reactive forms in Angular, the FormControl object is responsible for tracking the value and validation status of an individual form control. It represents a single input field and provides various methods and properties to manage its value and validation. FormArray and FormGroup are used for managing collections of controls or nested groups of controls, but FormControl is used for individual controls.
In the Angular route configuration, the children property is used to define ________.
- Child routes
- Parent routes
- Query parameters
- Route parameters
In Angular, the children property in the route configuration is used to define child routes. Child routes allow you to nest routes within other routes, creating a hierarchical navigation structure.
How can you selectively project content using the directive?
- By specifying a select attribute with a matching value.
- By using the
directive. - By using CSS selectors in the component's styles.
- By using JavaScript to manipulate the DOM.
To selectively project content using the directive in Angular, you can use the select attribute and specify a matching value. This allows you to target specific content for projection based on the provided attribute value. The other options are not correct methods for content projection in Angular.