Angular's structural directives change the DOM layout by adding and removing DOM elements. For example:
<div *ngIf="hero">{{ hero }}</div>
<div *ngFor="let hero of heroes">{{ hero }}</div>
<div [ngSwitch]="status">
<template [ngSwitchWhen]="'in-mission'">In Mission</template>
<template [ngSwitchWhen]="'ready'">Ready</template>
<template ngSwitchDefault>Unknown</template>
</div>