<div class="frame">

  <div class="display">
    <div *ngIf="display == ''" > EMPTY DISPLAY </div>
    <div> {{display}} </div>
  </div>

  <div class="grid-container">
    <button type="button" *ngFor="let b of btns" [ngClass]="b.nclass"
            (click)="onBtnClick(b)"> {{b.label}}
    </button>
  </div>

</div>