@Component({
  selector: 'zippy',
  template: `
  ‹div class="zippy">
    ‹div (click)="toggle()"›Toggle‹/div›
    ‹div [hidden]="!visible"›
      ‹ng-content>‹/ng-content›
    ‹/div›
  ‹/div›`})
 
export class ZippyComponent {
  visible = true;
  @Output() open = new EventEmitter‹any›();
  @Output() close = new EventEmitter‹any›();
 
  toggle() {
    this.visible = !this.visible;
    if (this.visible) {
      this.open.emit(null);
    } else {
      this.close.emit(null);
    }
  }
}