You want to track the time taken for a user to navigate from one page to another in your Angular application. Which Router Events can be useful for this purpose?
- NavigationEnd and RoutesRecognized
- NavigationStart and NavigationCancel
- NavigationStart and NavigationEnd
- NavigationStart and NavigationError
To track the time taken for navigation, you can use NavigationStart and NavigationEnd Router Events. The NavigationStart event marks the start of navigation, and NavigationEnd marks the end. Combining them allows you to measure the time taken.
To share a single subscription among multiple subscribers and turn a cold observable into a hot one, you can use the _____.
- Collect
- Connect
- Merge
- Share
To share a single subscription among multiple subscribers and turn a cold observable into a hot one, you can use the Share operator. This allows multiple subscribers to share the same execution of the observable, reducing duplicate work.
What is the purpose of Angular's built-in debugger statement?
- To debug TypeScript code
- To optimize performance
- To provide error messages
- To stop execution
The purpose of Angular's built-in debugger statement is to debug TypeScript code by pausing execution at a specific point in the code for inspection and troubleshooting.
What does the ng add command do in Angular CLI?
- Add a new component
- Add a new dependency
- Generate a service using the CLI
- Remove an existing component
The ng add command in Angular CLI is used to add a new dependency to the Angular project, such as a library or package.
How can you use a different class or value in place of a service in testing or certain scenarios?
- Dependency injection
- Extending the service class
- Mocking
- Using abstract classes
You can use a different class or value in place of a service in testing or specific scenarios by mocking the service using testing libraries or creating custom mock objects.
What is a potential consequence of not unsubscribing from an observable in an Angular component?
- Better application responsiveness
- Improved performance
- Memory leaks
- Reduced CPU usage
Not unsubscribing from an observable in an Angular component can lead to memory leaks, as the subscription remains open, causing resources to accumulate over time.
In Jasmine, to ensure that an asynchronous operation has completed before continuing the test, you can use the _____ function.
- afterEach()
- spyOnAsync()
- tick()
- waitForAsync()
In Jasmine, to ensure that an asynchronous operation has completed before continuing the test, you can use the tick() function.
You need to create a custom directive that changes the background color of an element when the user hovers over it. What Angular concepts and decorators would you use to achieve this?
- Apply styles directly in the component's HTML template
- Implement ngOnChanges to track changes in the element's state
- Use @HostListener to handle hover events
- Utilize @ViewChild to access the element and manipulate its styles
To create a custom directive that changes the background color on hover, you would use the @HostListener decorator to handle hover events and apply the desired behavior.
To reactively listen to changes to route parameters in Angular, you should use the _____ property of the ActivatedRoute service.
- paramMap
- paramsChanged
- routeChange
- routeParams
To reactively listen to changes to route parameters in Angular, you should use the paramMap property of the ActivatedRoute service.
In Angular, the method used to add a new form control to a FormArray dynamically is ____.
- addFormControl
- appendControl
- createControl
- pushControl
In Angular, the method used to add a new form control to a FormArray dynamically is appendControl. This method allows you to dynamically add a new form control to an existing FormArray.