title: Detect scroll - Ionic 4
body: <p>I'm trying to detect when I scroll up with:</p>
  
  <pre><code>&lt;ion-infinite-scroll (ionInfinite)="doInfinite($event)" scrollY="true"&gt;
     &lt;ion-infinite-scroll-content&gt;&lt;/ion-infinite-scroll-content&gt;
  &lt;/ion-infinite-scroll&gt;
  </code></pre>
  
  <p>Before with Ionic 3 I detected it in the following way:</p>
  
  <pre><code>  doInfinite(infiniteScroll) {
  
      this.infiniteScroll = infiniteScroll;
      if(infiniteScroll._content.directionY == "up"){
         //paginate
      }
    }
  </code></pre>
  
  <p>But now with Ionic 4 I do not know how to detect 'directionY'</p>
  
  <p>A greeting</p>