Answers for "ng add class"

add classon ng if

[ngClass]="{'my-class': step === 'step1'}"

angualr add class to component

@Component({
   selector: 'app-your-component',
   templateUrl: './your-component.component.html',,
   host: {'class': 'your-class'}
})
export class YourComponent implements OnInit {
...
}