calling angular component method in service

1// -------------------------------------------------------------------------------------
2// codes for component
3import { JustAService} from '../justAService.service';
4@Component({
5  selector: 'app-cute-little',
6  templateUrl: './cute-little.component.html',
7  styleUrls: ['./cute-little.component.css']
8})
9export class CuteLittleComponent implements OnInit {
10  s: JustAService;
11  a: number = 10;
12  constructor(theService: JustAService) {
13    this.s = theService;
14  }
15
16  ngOnInit() {
17    this.s.onSomethingHappended(this.doThis.bind(this));
18  }
19
20  doThis() {
21    this.a++;
22    console.log('yuppiiiii, ', this.a);
23  }
24}
25// -------------------------------------------------------------------------------------
26// codes for service
27@Injectable({
28  providedIn: 'root'
29})
30export class JustAService { 
31  private myFunc: () => void;
32  onSomethingHappended(fn: () => void) {
33    this.myFunc = fn;
34    // from now on, call myFunc wherever you want inside this service
35  }
36}
37