playground/lib/overview_component.html

<h1 #h1>Showing {{items.length}} items:</h1>

<li *ngFor='let item of items; var x=index' [hidden]='item != null'>
    {{x}}: {{item}}
</li>

<button (click)="items.add('hey');" *ngIf="items.length == 0" bubbled #bubble="bubble">{{bubble.width}}</button>
<button (click)="h1.hidden = !h1.hidden">Hide header</button>

<my-counter [count]='4' (incremented)='items.add($event.toString())'></my-counter>

<my-counter></my-counter>