static/js/pager: Avoid async conflict between track and restore

1 files changed, 11 insertions, 9 deletions

diff --git a/static/js/pager.ts b/static/js/pager.ts
index cb7f8a4..3f9beaf 100644
--- a/static/js/pager.ts
+++ b/static/js/pager.ts
@@ -12,23 +12,24 @@
   const key = "settings";
   const url = self.location.href.split("#")[0].split("?")[0];
 
+  if (!localStorage[key]) localStorage[key] = JSON.stringify(settings);
+
   const scrollRestore = function (url) {
     if (history.scrollRestoration) history.scrollRestoration = "manual";
-    if (localStorage[key]) settings = JSON.parse(localStorage[key]);
-    const fragment = document.getElementById(location.hash.slice(1));
+    settings = JSON.parse(localStorage[key]);
+    const fragment = self.location.hash.slice(1) &&
+      document.getElementById(self.location.hash.slice(1));
     const fragmentInURL = self.location.hash.length > 0;
     if (fragmentInURL && document.body.contains(fragment)) {
       settings["pager"][url] = self.pageYOffset;
       localStorage[key] = JSON.stringify(settings);
       fragment.scrollIntoView();
-      self.addEventListener("DOMContentLoaded", function () {
+      return self.addEventListener("DOMContentLoaded", function () {
         fragment.scrollIntoView();
       });
-      return;
     }
     if (settings["pager"][url] > 0) {
-      self.scrollTo(0, settings["pager"][url]);
-      return;
+      return self.scrollTo(0, settings["pager"][url]);
     }
     settings["pager"][url] = self.pageYOffset;
     localStorage[key] = JSON.stringify(settings);
@@ -36,11 +37,12 @@
 
   const scrollTrack = function (url) {
     const currentPosition = self.pageYOffset;
+    settings = JSON.parse(localStorage[key]);
     settings["pager"][url] = currentPosition;
     localStorage[key] = JSON.stringify(settings);
   };
 
-  const backTrack = function (back, up, event) {
+  const reverseTrack = function (back, up, event) {
     if (document.body.contains(up) && up.contains(event.target)) {
       event.preventDefault();
       window.scrollTo(0, 0);
@@ -57,7 +59,7 @@
     self.addEventListener("click", function (event) {
       const up = document.getElementById("top");
       const back = document.getElementById("back");
-      backTrack(back, up, event);
+      reverseTrack(back, up, event);
     });
   });
 
@@ -66,7 +68,7 @@
   });
 
   ["click", "touchstart", "scroll"].forEach(function (event) {
-    self.addEventListener(event, function (event) {
+    self.addEventListener(event, function () {
       scrollTrack(url);
     });
   });