You are tasked with improving the performance of an Angular application. One strategy is to split the application into smaller, feature-specific modules. How would you implement lazy loading for these modules?
- Define modules in the main application file and load them dynamically
- Manually load modules when needed
- Use Angular's loadChildren route configuration
- Use a third-party library for lazy loading
To implement lazy loading for feature-specific modules in an Angular application, you would use the loadChildren route configuration to load modules on demand.
When does a cold observable start emitting values?
- After a timeout set by the developer.
- Immediately upon creation.
- When explicitly triggered by calling a method.
- When subscribed to by at least one observer.
A cold observable starts emitting values when subscribed to by at least one observer, and each observer gets its independent sequence of values.
The Ivy Renderer’s instruction set allows Angular to be more efficient in updating the DOM by avoiding the need for a _____.
- Browser Update Cycle
- Change Detection
- Template Engine
- Virtual DOM
The Ivy Renderer’s instruction set allows Angular to be more efficient in updating the DOM by avoiding the need for Change Detection, reducing the overhead of checking for changes in the application's data and view.
How can you simulate user interactions with an element when testing a directive?
- Use ComponentFixture.nativeElement
- Use TestBed.configureTestingModule()
- Use TestBed.get()
- Use TestBed.inject()
To simulate user interactions when testing a directive, you can use the ComponentFixture.nativeElement to interact with the element.
Which property of the NavigationExtras object allows you to preserve query parameters across multiple navigation operations?
- preserveQueryParams
- queryParamsHandling
- queryParamsPersistence
- saveQueryParameters
The queryParamsHandling property of the NavigationExtras object is used to preserve query parameters across multiple navigation operations.
You are developing a real-time dashboard that needs to display data from multiple API endpoints. Which RxJS operators can help you effectively combine and manage the data from these endpoints?
- filter and combineLatest
- map and catchError
- mergeMap and forkJoin
- reduce and debounceTime
In this scenario, you can use mergeMap to merge and flatten multiple observables, and forkJoin to wait for all observables to complete and return their results. This combination is effective for handling data from multiple API endpoints in a real-time dashboard.
Which Angular lifecycle hook is invoked when the value of an input property changes?
- ngAfterViewInit
- ngDoCheck
- ngOnChanges
- ngOnInit
The Angular lifecycle hook ngOnChanges is invoked when the value of an input property changes. Developers can use this hook to respond to input property changes.
How can you ensure that a lazily-loaded module is only downloaded when a specific condition is met?
- It's not possible
- Use canActivate guard
- Use loadChildren in the route configuration
- Use resolver for data preloading
To ensure that a lazily-loaded module is downloaded only when a specific condition is met, you can use the loadChildren property in the route configuration.
The _____ file in Protractor allows you to specify settings such as the Selenium address and test files.
- conf.js
- protractor-config.js
- protractor.conf
- protractor.json
The Protractor configuration file is typically named conf.js and is used to specify settings for the Protractor test suite.
How can you ensure that your custom pipe is recalculated only when the input values change?
- Call the ngOnChanges lifecycle hook on the pipe
- Implement the OnPush change detection strategy
- Use the @Input decorator on the pipe
- Use the pure property in the @Pipe decorator
You can ensure that your custom pipe is recalculated only when the input values change by setting the pure property in the @Pipe decorator to true.