move load posts into separate function

js/src/forum/components/PostStream.js

@@ -142,13 +142,28 @@ export default class PostStream extends Component {
   }
 
   /**
-   * When the window is scrolled, check if either extreme of the post stream is
-   * in the viewport, and if so, trigger loading the next/previous page.
    *
    * @param {Integer} top
    */
   onscroll(top = window.pageYOffset) {
     if (this.stream.paused) return;
+    this.loadPostsWhenNeeded(top);
+
+    // Throttle calculation of our position (start/end numbers of posts in the
+    // viewport) to 100ms.
+    clearTimeout(this.calculatePositionTimeout);
+    this.calculatePositionTimeout = setTimeout(this.calculatePosition.bind(this, top), 100);
+
+    this.updateScrubber(top);
+  }
+
+  /**
+   * Check if either extreme of the post stream is in the viewport,
+   * and if so, trigger loading the next/previous page.
+   *
+   * @param {Integer} top
+   */
+  loadPostsWhenNeeded(top = window.pageYOffset) {
     const marginTop = this.getMarginTop();
     const viewportHeight = $(window).height() - marginTop;
     const viewportTop = top + marginTop;
@@ -169,13 +184,6 @@ export default class PostStream extends Component {
         this.stream.loadNext();
       }
     }
-
-    // Throttle calculation of our position (start/end numbers of posts in the
-    // viewport) to 100ms.
-    clearTimeout(this.calculatePositionTimeout);
-    this.calculatePositionTimeout = setTimeout(this.calculatePosition.bind(this, top), 100);
-
-    this.updateScrubber(top);
   }
 
   updateScrubber(top = window.pageYOffset) {
@@ -394,8 +402,8 @@ export default class PostStream extends Component {
 
       this.calculatePosition();
       this.stream.paused = false;
-      // Run the onscroll handler to check if we need to load more posts after scrolling.
-      this.onscroll();
+      // Check if we need to load more posts after scrolling.
+      this.loadPostsWhenNeeded();
     });
   }