angular-cn/aio/src/app/embedded/toc/toc.component.html

<div *ngIf="hasToc" [class.closed]="isClosed">
  <div *ngIf="!hasSecondary" class="toc-heading">Contents</div>
  <div *ngIf="hasSecondary" class="toc-heading secondary"
      (click)="toggle(false)"
      title="Expand/collapse contents"
      aria-label="Expand/collapse contents">
      <p>Table of Contents<button type="button" class="toc-show-all material-icons" [class.closed]="isClosed"></button></p>
  </div>

  <ul class="toc-list">
    <li *ngFor="let toc of tocList" title="{{toc.title}}" class="{{toc.level}}" [class.secondary]="toc.isSecondary">
      <a [href]="toc.href" [innerHTML]="toc.content"></a>
    </li>
  </ul>

  <button type="button" (click)="toggle()" *ngIf="hasSecondary"
    class="toc-more-items material-icons" [class.closed]="isClosed"
    title="Expand/collapse contents"
    aria-label="Expand/collapse contents">
  </button>
</div>