import { Subject } from 'rxjs/Subject'; // to emit errors import { Subscription } from 'rxjs/Subscription'; // to subscribe to the emiter

@Component({ ... })

export class MyComponent OnInit, OnDestroy {

private subscription:Subscription = new Subscription();

constructor(
    private errorService: ErrorService,
) {}
ngOnInit(){
    this.subscription = this.errorService.error.subscribe(
        error => console.log(error)
    );
}
ngOnDestroy(){
    this.subscription.unsubscribe();
}

}