Angular ng-content with default content

When I faced the problem of setting a default content, my first thought was to put the content inside the <ng-content> tags, but that didn't work. You will not find this in the Angular docs, but there is a workaround.

<div class="header">...</div>
<div #contentRef class="content">
<div *ngIf="contentRef.childNodes.length === 0" class="content">
    default content
<div class="footer">...</div>