Scoped Services in Angular

Scoped services in Angular are services that are provided at the module level, creating a separate instance for each module that imports them. This allows for data isolation and encapsulation within the scope of a specific module.

Understanding Scoped Services

Scoped services are provided within a specific module using the providers array of that module:

// my.service.ts
import { Injectable } from '@angular/core';

@Injectable()
export class MyService {
  constructor() { }

  getMessage(): string {
    return 'Hello from MyService!';
  }
}

Providing Scoped Services

To provide a service scoped to a specific module, include it in the providers array of that module:

// my-module.module.ts
import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { MyService } from './my.service';
import { MyComponent } from './my.component';

@NgModule({
  declarations: [MyComponent],
  imports: [CommonModule],
  providers: [MyService]
})
export class MyModule { }

Injecting Scoped Services

Scoped services can be injected into components, directives, or other services within the same module. Angular ensures that each module has its own instance of the scoped service:

// my.component.ts
import { Component } from '@angular/core';
import { MyService } from './my.service';

@Component({
  selector: 'app-my-component',
  template: '
{{ message }}
',
})
export class MyComponent {
  message: string;

  constructor(private myService: MyService) {
    this.message = this.myService.getMessage();
  }
}

Benefits of Scoped Services

Scoped services offer several benefits:

• Data isolation: Each module has its own instance of the scoped service, ensuring data isolation and encapsulation.
• Encapsulation: Scoped services promote encapsulation by limiting the visibility of services to specific modules.
• Module-specific functionality: Scoped services are tailored to the needs of a specific module, improving modularity and maintainability.

Key Points

Conclusion

Scoped services in Angular provide a powerful mechanism for encapsulating functionality within the scope of specific modules. By understanding and leveraging scoped services, you can create modular and maintainable Angular applications with ease.