Thursday 15 February 2024

What is the role of @Injectable Decorator in a Service Angular?036

 What is the role of @Injectable Decorator in a Service Angular?

In Angular, the @Injectable decorator plays a crucial role in service creation and dependency injection. Here's a breakdown of its key functions:

1. Declares a Service:

  • Marks a class as a service, making it eligible for dependency injection throughout your application.

  • Enables Angular to recognize it as a provider of functionality and data.

2. Configures the Service:

  • Allows you to specify configuration options for the service using the decorator's properties:

  • providedIn: Sets the scope of the service, determining where it's available (root injector, component, module).

  • factory: Provides a custom function for creating the service instance (optional).

3. Enables Dependency Injection:

  • Services marked with @Injectable can be injected into other components, services, or directives using constructor injection.

  • Angular uses the configured provider to create and provide the service instance when needed.

4. Enforces Best Practices:

  • Encourages you to define services as separate classes, promoting modularity and reusability.

  • Reminds you about the importance of providing dependencies through constructor injection.



@Injectable({ providedIn: 'root' })
export class MyService {
  // Service logic and properties

This example creates a MyService with root-level scope, meaning it's available throughout the application.

Benefits of Using @Injectable:

  • Clear code organization: Separates service-specific logic from components, promoting readability and maintainability.

  • Dependency management: Enables the dependency injector to handle service creation and provide them where needed.

  • Flexibility: Configurable scopes allow precise control over service availability.

  • Testing: Enforces constructor injection, which simplifies service mocking for testing.


  • Use @Injectable for all classes intended as services in your Angular application.

  • Choose the appropriate providedIn scope based on your service's usage.

  • Consider using factory providers for advanced customization during service creation.

By effectively using the @Injectable decorator, you can structure your Angular services efficiently and leverage dependency injection for cleaner and more robust applications. Feel free to ask if you have any further questions or specific service use cases!

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