Angular Web Framework Services & Dependency Injection

Question 1

What is a service in Angular?

Accepted Answer

A class with a focused purpose that provides shared functionality across components

Answer

Angular services are TypeScript classes decorated with @Injectable() that encapsulate reusable business logic, data access, or utility functions that can be shared across multiple components.

Question 2

What is dependency injection (DI) in Angular?

Accepted Answer

A design pattern where dependencies are provided to a class rather than created by it

Answer

Angular's DI system creates and provides instances of services to components and other services that declare dependencies, promoting loose coupling and testability.

Question 3

What does 'providedIn: root' mean in an @Injectable() decorator?

Accepted Answer

The service is available application-wide as a singleton through the root injector

Answer

'providedIn: root' registers the service with the root injector, making a single instance available throughout the entire application and enabling tree-shaking of unused services.

Question 4

What is the purpose of HttpClient in Angular?

Accepted Answer

To make HTTP requests to APIs and external services

Answer

HttpClient is Angular's built-in service for making HTTP requests (GET, POST, PUT, DELETE) to backend APIs, returning Observables that can be subscribed to for response handling.

Question 5

What is an interceptor in Angular?

Accepted Answer

A service that intercepts and optionally modifies HTTP requests or responses globally

Answer

HTTP interceptors sit between the application and the HTTP client, allowing global modification of outgoing requests (adding auth tokens) or incoming responses (error handling).

Angular Web Framework Practice Test

Angular Web Framework Practice Test

Angular Web Framework Services & Dependency Injection