‹div›
  Pick your favorite hero
  (‹label›‹input type="checkbox" checked (change)="showSad = !showSad"›show sad‹label›)
‹/div›
‹select [(ngModel)]="hero"›
  ‹ng-container *ngFor="let h of heroes"›
    ‹ng-container *ngIf="showSad || h.emotion !== 'sad'"›
      ‹option [ngValue]="h"›{{h.name}} ({{h.emotion}})‹/option›
    ‹/ng-container›
  ‹/ng-container›
‹select›