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Why is it recommended to use immutable data structures with the OnPush change detection strategy?

  • Immutable data structures are Angular's requirement.
  • Immutable data structures are easier to use.
  • Immutable data structures are faster.
  • Immutable data structures help avoid side effects.
It is recommended to use immutable data structures with the "OnPush" change detection strategy because immutable data structures help avoid side effects. In Angular, when you change an input property's value, it triggers change detection. Using mutable objects can lead to unintended changes and unexpected behavior. Immutable data structures ensure that once a value is set, it remains unchanged, making it easier to reason about component behavior and performance optimization.
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In Angular, to define routes for an application, you typically create an array of ________ objects.

  • Component
  • Module
  • Route
  • RouterModule
In Angular, to define routes for an application, you typically create an array of Route objects. These objects define the mapping between routes and components, specifying which component should be displayed when a particular route is navigated to. The RouterModule is indeed used to set up the routing configuration in an Angular application, but it's not an array. Components and modules are essential parts of Angular, but they are not used directly to define routes.
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When making an HTTP request using the HttpClient, what type of object is returned?

  • Object
  • Observable
  • Promise
  • Response
When making an HTTP request using HttpClient, an Observable object is returned. Observables are used to handle asynchronous data streams and provide features like error handling and transformation, making them well-suited for managing HTTP responses.
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Which Route Guard allows you to check whether a user can activate a particular route?

  • CanActivate
  • CanActivateChild
  • CanDeactivate
  • CanLoad
The 'CanActivate' Route Guard is used to check whether a user can activate a particular route. It's commonly used for protecting routes based on authentication or other conditions. This guard determines if a user has permission to access a specific route and is typically used to secure routes in Angular applications. The other guards have different roles, such as 'CanActivateChild' for protecting child routes and 'CanDeactivate' for confirming navigation away from a component.
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How can you ensure that a particular component is checked only once by Angular's change detection mechanism?

  • Using the ChangeDetectionStrategy.OnPush strategy.
  • Wrapping the component in an async pipe.
  • Manually triggering change detection for that component.
  • Adding the component to the AppModule declarations array.
You can ensure that a particular component is checked only once by Angular's change detection mechanism by using the ChangeDetectionStrategy.OnPush strategy. This strategy tells Angular to only run change detection on a component when its input properties change or when you manually trigger it. The other options do not provide a way to control change detection behavior in the same way.
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In which scenario is it NOT recommended to use ChangeDetectionStrategy.OnPush?

  • When a component has complex view logic with many nested components
  • When a component is stateful and has user interactions triggering updates
  • When a component relies on frequent data updates from external sources
  • When optimizing for performance is a top priority
ChangeDetectionStrategy.OnPush is not recommended when a component relies on frequent data updates from external sources because it can lead to manual triggering of change detection, reducing the benefits of this strategy. It's more suitable for components with infrequent updates or performance optimization.
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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.
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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.
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When configuring the Angular Router for lazy loading, the loadChildren property points to a function that uses the ______ syntax to load the module.

  • Import()
  • fetch()
  • load()
  • require()
In Angular, when configuring lazy loading for the Angular Router, the loadChildren property points to a function that uses the import() syntax to load the module on-demand. This allows for efficient code splitting and loading modules only when they are needed, improving application performance.
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In multi-slot content projection, how can you differentiate between the different content slots?

  • By adding custom attributes to the elements.
  • By creating separate child components for each slot.
  • By using Angular directives like *ngIf and *ngFor.
  • By using unique CSS classes for each tag.
In multi-slot content projection, you can differentiate between different content slots by using unique CSS classes for each tag. This approach allows you to style and target each slot individually based on the CSS class applied. Adding custom attributes or using directives like *ngIf and *ngFor do not inherently differentiate slots; they are used for other purposes. Creating separate child components for each slot is a more complex alternative.
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If a service is provided both at the module level and the component level, which instance will the component receive?

  • The component will receive both instances.
  • The component will receive the component-level instance.
  • The component will receive the module-level instance.
  • The component will throw an error.
In Angular (or similar frameworks), when a service is provided both at the module and component levels, the component will receive the component-level instance. This is known as "shadowing." The component-level instance takes precedence over the module-level one. The scenario where a component receives both instances is not valid, and it will result in an error.
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For which purpose might you consider using dynamic components in Angular?

  • Defining application routes
  • Lazy loading of modules
  • Optimizing database queries by default
  • Styling components dynamically
Dynamic components in Angular are often used for lazy loading of modules. This allows you to load parts of your application on-demand, improving initial loading times and overall performance. While Angular uses routes to define application navigation, dynamic components are not used for this specific purpose. They are also not primarily used for styling components dynamically or optimizing database queries.
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