app/js/index.js in servel-0.23.0 vs app/js/index.js in servel-0.24.0

@@ -1,24 +1,77 @@
 "use strict";
 
 var Index = (function() {
+  function galleryVisible() {
+    return document.body.classList.contains("gallery");
+  }
+
+  function listingVisible() {
+    return document.body.classList.contains("listing");
+  }
+
   function jumpListing() {
     document.body.classList.remove("gallery");
     document.body.classList.add("listing");
   }
 
   function jumpGallery() {
     document.body.classList.remove("listing");
     document.body.classList.add("gallery");
   }
 
+  function jumpScroll() {
+    if(galleryVisible()) {
+      jumpListing();
+      window.scrollTo(0, 0);
+    }
+    else {
+      jumpGallery();
+      window.scrollTo(0, document.body.scrollHeight);
+    }
+  }
+
+  function atTop() {
+    return window.scrollY == 0;
+  }
+
+  function bottomScrollDown(event) {
+    return galleryVisible() && atBottom() && event.deltaY > 0;
+  }
+
+  function topScrollUp(event) {
+    return listingVisible() && atTop() && event.deltaY < 0;
+  }
+
+  function initEvents() {
+    var scrollSize = 0;
+
+    window.addEventListener("wheel", function(event) {
+      if(bottomScrollDown(event) || topScrollUp(event)) {
+        scrollSize += Math.abs(event.deltaY);
+
+        if(scrollSize >= 1500) {
+          scrollSize = 0;
+          jumpScroll();
+        }
+      }
+      else {
+        scrollSize = 0;
+      }
+    });
+  }
+
   function init() {
-    if(document.body.classList.contains("has-gallery")) jumpGallery();
+    if((Entries.media().length / Entries.all().length) >= 0.5) jumpGallery();
     else jumpListing();
+
+    initEvents();
   }
 
   return {
     init: init,
+    galleryVisible: galleryVisible,
+    listingVisible: listingVisible,
     jumpListing: jumpListing,
     jumpGallery: jumpGallery
   };
 })();
 
\ No newline at end of file