title: ES6 double destructure
body: <p>I understand this probably is a pretty basic question, but I'm not proficient with ES6 and I've encountered this syntax:</p>
  
  <pre><code>const { rootStore: { routerStore } } = this.props;
  </code></pre>
  
  <p>I understand what something like this means:</p>
  
  <pre><code>const { rootStore } = this.props;
  </code></pre>
  
  <p>(Creating a const <code>rootStore</code> from the property <code>rootStore</code> in <code>this.props</code>).</p>
  
  <p>But what does the above double deconstruction (I assume it's deconstruction) mean?</p>