buttons.html

  <div class="btn-group" data-toggle="buttons">
    <label class="btn btn-primary" [class.active]="model.left">
      <input type="checkbox" [(ngModel)]="model.left"> Left (pre-checked)
    </label>
    <label class="btn btn-primary" [class.active]="model.middle">
      <input type="checkbox" [(ngModel)]="model.middle"> Middle
    </label>
    <label class="btn btn-primary" [class.active]="model.right">
      <input type="checkbox" [(ngModel)]="model.right"> Right
    </label>
  </div>