Question

What does the Angular injector subsystem do?

Option 1:
Manages dependency injection and maintains a container for service instances.

Option 2:
Handles HTTP requests and manages data caching.

Option 3:
Organizes UI components and directives in Angular applications.

Option 4:
Controls the rendering of templates and views.

Answer 1

The Angular injector subsystem manages dependency injection and creates instances of services needed by components and directives in an Angular application.

Step-by-step explanation:

The Angular injector subsystem is responsible for managing dependency injection and maintaining a container for service instances.

Dependency injection is a design pattern in which the dependencies of an object are provided externally, rather than being created within the object itself. The Angular injector manages these dependencies and creates instances of services that are needed by components, directives, or other services in an Angular application.

For example, if a component needs access to a service that provides data from an API, the injector is responsible for creating an instance of that service and injecting it into the component.

Answer 2

The Angular injector subsystem manages dependency injection and maintains a container for service instances, which aligns with Option 1. It is a key aspect of Angular that promotes modularity, testability, and maintainability in applications.

Step-by-step explanation:

Understanding the Angular Injector Subsystem

The Angular injector subsystem is responsible for managing dependency injection and maintaining a container for service instances. This means that the correct answer to the student's question is Option 1. The injector is a core feature of Angular that allows developers to define dependencies for their components and services. Instead of instantiating service classes directly, Angular components declare their dependencies, and the injector supplies them with instances of these services.

When a component requires a service, the Angular injector checks if an instance of the service exists in its container. If not, it creates one using the provided service class and adds it to the container for future usage. This approach adheres to the principle of inversion of control, making the code more modular, testable, and maintainable.

The injector does not handle HTTP requests (that's the job of the HttpClient service) nor manage UI components (this is the role of Angular's component and directive systems). Also, the injector isn't directly involved in controlling the rendering of templates and views, which is handled by Angular's change detection and rendering mechanisms.