How to pass two different templates into one directive and let the directive decide showing which one over time?
<p>I am building a Expand/ Collapse button with Angular2 and I will reuse this directive over different pages with different templates and UI.</p>

<p>After searching I still can't find the correct way to make it works.</p>

<p><code>&lt;ng-content /&gt;</code>? <code>&lt;template /&gt;</code>? <code>TemplateRef</code>? How to do it correctly?</p>