Sintaxe para Ngfor
<ul>
<li *ngFor="let item of items; let i = index" [attr.data-index]="i">
{{item}}
</li>
</ul>
2 Programmers 1 Bug
<ul>
<li *ngFor="let item of items; let i = index" [attr.data-index]="i">
{{item}}
</li>
</ul>
<li *ngFor="let item of items; index as i; trackBy: trackByFn">...</li>
<h1 *ngFor="let item of Demo"></h1>