Question 1

What are Angular services?

Accepted Answer

Angular services are reusable code modules that execute specific functions or provide functionality throughout an application. They can encapsulate any logic that developers want to centralize and share. Typically, a service is used to handle tasks such as data fetching, data storage, logging, or managing application state. Services are designed to be injected into components or other services, allowing them to be easily shared and utilized across the entire application.

Question 2

Why do we need Angular services?

Accepted Answer

Angular applications use services to keep certain program logic organized, reusable, and shareable. They help separate concerns by handling data and logic operations apart from the components that display information. This separation makes it easier to update and maintain the logic efficiently.

Question 3

What is dependency injection?

Accepted Answer

Dependency Injection (DI) is a programming design pattern in which objects obtain their dependencies from outside sources instead of generating them on their own. In Angular, the framework takes charge of creating and managing the lifecycle of the objects that components and services need. Dependency injection fosters modularity and reduces coupling between different parts of an application; making it easier to reuse logic and update them during the development lifecycle of an application.

Question 4

How does dependency injection work?

Accepted Answer

Angular's dependency injection system operates through a network of injectors and providers. When a component or service needs a dependency, Angular's injectors search for the appropriate provider, which is a set of instructions on creating that dependency based on its class. Providers are registered within components or directives, defining how instances of these dependencies should be created. When a class requests a dependency, Angular first checks the component's own registered providers to see if it can fulfill the request there. If it doesn't find the required service in the component, it searches through parent components in the hierarchy. Finally, if necessary, it checks the root injector, which serves as a global source for all services in the application. This structured approach ensures that elements of an application can efficiently access the resources they need without duplicating code.

Angular Services and Dependency Injection

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