Wednesday 14 February 2024

What are the types of Decorator Angular?028

 What are the types of Decorator Angular?

In Angular, decorators are powerful tools for adding information and functionality to various aspects of your application. Here's a breakdown of the different types of decorators you can use:

1. Class Decorators:

  • Define the role and functionality of a class. Common examples include:

  • @Component: Marks a class as an Angular component with its template, styles, and logic.

  • @Directive: Denotes a class as a custom directive to modify element behavior or appearance.

  • @Injectable: Identifies a class as a service eligible for dependency injection throughout the application.

  • @NgModule: Defines a module, the fundamental building block of Angular applications, grouping components, directives, and services.

2. Property Decorators:

  • Control how properties interact with data flow between components and services. Common examples include:

  • @Input: Allows a component to receive data from its parent component through property binding.

  • @Output: Enables a component to emit events that its parent component can listen to.

  • @ViewChild: Provides access to a child component instance from its parent component.

  • @ContentChild: Similar to @ViewChild, but accesses a projected content child component.

3. Method Decorators:

  • Attach behavior to methods within a class, often related to events or lifecycle hooks. Common examples include:

  • @HostListener: Listens to DOM events occurring on the host element of a component or directive.

  • @HostBinding: Binds a component property to a host element attribute or property.

  • @OnInit: Lifecycle hook that runs after a component is initialized.

  • @OnChanges: Lifecycle hook that runs when a component's input properties change.

4. Parameter Decorators:

  • Specify how dependencies are injected into a class constructor. Common examples include:

  • @Inject: Allows you to explicitly specify a custom provider for a dependency instead of relying on the default mechanism.

  • @Optional: Marks a dependency as optional, indicating it might not always be available.


  • Decorators are processed during compilation, ensuring potential errors are caught early.

  • Choosing the right decorator and understanding its implications is crucial for building well-structured and efficient Angular applications.

  • Many additional custom decorators can be created to extend Angular's functionality for specific needs.

I hope this clarifies the different types of decorators in Angular. Feel free to ask if you have any further questions or specific use cases you'd like to explore!

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