Services and Dependencies in Angular

What are Services in Angular?

  Services in Angular are classes that encapsulate business logic and data, allowing their reuse in different components. They are fundamental for keeping the code clean and organized.

• Facilitate the separation of responsibilities.
• Allow sharing data and functions between components.
• Improve the maintainability and scalability of the application.

Dependency Injection (DI)

  Dependency Injection is a design pattern that allows components to obtain their dependencies instead of creating them themselves. Angular uses DI to manage the creation and provision of services.

• Reduces coupling between components and services.
• Facilitates unit testing.
• Improves code modularity.

Providers: Configuring Injection

  Providers define how service instances are created. They are configured in modules or components and specify which class should be instantiated when a service is requested.

  Example of a provider in a module:

@NgModule({
  providers: [MyService]
})

Singleton: One Instance for All

  By default, Angular services are Singletons, which means that a single instance of the service is created and shared throughout the application. This ensures consistency and performance.

  However, providers can be configured to create multiple instances if necessary.