Web / Angular Interview questions

How do I create a service as a singleton in Angular?

We can create a service as singleton in Angular in 2 ways:

Declare that the service should be provided in the application root. This is done by setting providedIn to root on the service's @Injectable decorator as shown below. This is the preferred way to create a singleton service starting Angular 6.
```
import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root',
})
export class UserService {
}
```
Include the service in the AppModule or in a module that is only imported by the AppModule.

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