added auto-scrolling for preview

src/zona/data/server/inject.js

@@ -1,6 +1,24 @@
+(() => {
+  // if user at the bottom before reload, scroll to new bottom
+  if (localStorage.getItem("wasAtBottom") === "1") {
+    localStorage.removeItem("wasAtBottom");
+    window.addEventListener("load", () => {
+      requestAnimationFrame(() => {
+        window.scrollTo(0, document.body.scrollHeight);
+      });
+    });
+  }
+
   const ws = new WebSocket("__SOCKET_ADDRESS_");
   ws.onmessage = event => {
     if (event.data === "reload") {
+      // store flag if user currently at bottom
+      const nearBottom = window.innerHeight + window.scrollY
+        >= document.body.scrollHeight - 100;
+      if (nearBottom) {
+        localStorage.setItem("wasAtBottom", "1");
+      }
       location.reload();
     }
   };
+})();