To dynamically create components at runtime, one should use the ________ service.
- ComponentFactoryResolver
- ChangeDetectionStrategy
- AngularInjector
- DependencyInjection
To dynamically create components at runtime in Angular, you should use the ComponentFactoryResolver service. This service allows you to resolve and create components dynamically, a valuable feature when dealing with dynamic UI elements or component-based applications. The other options are not related to dynamic component creation.
If a route's path is set as an empty string (''), it often represents the ________ route of the application.
- Default
- Home
- Primary
- Root
If a route's path is set to an empty string (''), it typically represents the Root route of the application. This means that when the application is accessed without any specific route, the route with an empty path ('') will be considered, often serving as the main entry point or home page of the application.
For guards that determine whether a module should be loaded or not, the method ______ should return a boolean or an observable that resolves to a boolean.
- canActivate
- canActivateChild
- canDeactivate
- canLoad
When working with guards that determine whether a module should be loaded or not, the canLoad method should return a boolean or an observable that resolves to a boolean. This guard is used to control the lazy loading of feature modules.
If you need to clear all views from a ViewContainerRef, you would use the ______ method.
- clearViews()
- emptyContainer()
- purgeViews()
- removeAll()
To clear all views from a ViewContainerRef in frameworks like Angular, you would use the emptyContainer() method. This method removes all attached views, providing a clean slate for rendering new components or views in the container. It's an important function for managing dynamic user interfaces.
How can you share a service instance between multiple lazy-loaded modules in Angular?
- Manually create a service instance in each lazy-loaded module
- Provide the service in a shared module and import that module into each lazy-loaded module
- Use Angular's built-in lazy-loading service provider
- Use the 'shared' attribute in the service decorator
To share a service instance between multiple lazy-loaded modules, you should provide the service in a shared module and then import that shared module into each of the lazy-loaded modules that need access to the service. This ensures that there's only one instance of the service across those modules.
To ensure a single instance of a service is available throughout the app, set the providedIn property to ________.
- 'app'
- 'root'
- 'shared'
- 'singleton'
To ensure a single instance of a service is available throughout the app, you should set the providedIn property to 'root'. This means that the service is provided at the application level, and there will be only one instance of the service for the entire app, making it a singleton service that can be injected into multiple components.
You are developing an Angular application where a child component needs to notify its parent component about certain events. Which mechanism would you use?
- @Input and @Output
- EventEmitter
- Subject
- ngModelChange Event
To have a child component notify its parent in Angular, you typically use the @Input and @Output decorators. The child component can send data or events to the parent component using @Output, creating a custom event emitter. EventEmitter can be used, but it's often associated with custom events. Subjects are used for more complex scenarios. The ngModelChange event is used for form input changes, not parent-child communication.
When an Observable is no longer needed, it should be ________ to prevent memory leaks.
- Composed
- Pipelined
- Subscribed
- Unsubscribed
To prevent memory leaks in Angular applications when an Observable is no longer needed, it should be unsubscribed. Failing to unsubscribe from Observables can lead to resource leaks, as they may continue to emit values and hold references to objects even after the component or service that used them is destroyed. Properly unsubscribing from Observables ensures that they are cleaned up and do not cause memory issues.
Custom attribute directives can alter the appearance or behavior of an element without changing its ________.
- CSS styles.
- HTML structure.
- JavaScript code.
- Original attributes or properties.
Custom attribute directives in Angular can alter the appearance or behavior of an element without changing its HTML structure. They can manipulate the element's behavior or appearance by binding to its properties or attributes, but they typically do not modify the fundamental structure of the HTML element. This allows for greater flexibility and reusability in Angular applications.
What is the purpose of the ControlValueAccessor interface in Angular forms?
- It is used to access form control values in JavaScript code.
- It enables custom form controls to work with Angular's reactive forms.
- It provides a way to access the values of a FormGroup.
- It allows you to control the layout of form elements in Angular templates.
The ControlValueAccessor interface in Angular forms is used to enable custom form controls to work seamlessly with Angular's reactive forms. It acts as a bridge between the custom form control and Angular's form infrastructure, allowing the control to interact with form directives, template-driven forms, and reactive forms. Options 1, 3, and 4 do not accurately describe the purpose of ControlValueAccessor.