list.component.ts

...
@Component({
  selector: 'list',
  templateUrl: './list.component.html',
  styleUrls: ['./list.component.scss']
})

export class ListComponent implements OnChanges {

  @Input() rows: Transaction[];

...

  public getRowClass(row: Transaction) {
    return {
      'active': this.trService.isActive(row),
      'rejected': this.trService.isRejected(row),
      'accepted': this.trService.isAccepted(row)
    };
  }

...

}