static/js/pager: Run on cache persistence

Run a limited seek interval

1 files changed, 18 insertions, 7 deletions

diff --git a/static/js/pager.ts b/static/js/pager.ts
index 3f9beaf..6133f21 100644
--- a/static/js/pager.ts
+++ b/static/js/pager.ts
@@ -7,6 +7,7 @@
     return console.log("Pager is disabled due to cookie restrictions.");
   }
 
+  let seek;
   let settings = { pager: {} };
 
   const key = "settings";
@@ -17,9 +18,9 @@
   const scrollRestore = function (url) {
     if (history.scrollRestoration) history.scrollRestoration = "manual";
     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;
+    const hash = self.location.hash;
+    const fragment = hash.slice(1) && document.getElementById(hash.slice(1));
+    const fragmentInURL = hash.length > 0;
     if (fragmentInURL && document.body.contains(fragment)) {
       settings["pager"][url] = self.pageYOffset;
       localStorage[key] = JSON.stringify(settings);
@@ -29,7 +30,13 @@
       });
     }
     if (settings["pager"][url] > 0) {
-      return self.scrollTo(0, settings["pager"][url]);
+      self.scrollTo(0, settings["pager"][url]);
+      let i = 0; return seek = setInterval(function (position) {
+        i++; if (i > 100) clearInterval(seek);
+        if (document.documentElement.scrollHeight >= position + document.documentElement.clientHeight) {
+          clearInterval(seek); self.scrollTo(0, position);
+        }
+      }, 4, settings["pager"][url]);
     }
     settings["pager"][url] = self.pageYOffset;
     localStorage[key] = JSON.stringify(settings);
@@ -55,7 +62,6 @@
   };
 
   self.addEventListener("DOMContentLoaded", function () {
-    scrollRestore(url);
     self.addEventListener("click", function (event) {
       const up = document.getElementById("top");
       const back = document.getElementById("back");
@@ -63,8 +69,13 @@
     });
   });
 
-  self.addEventListener("hashchange", function () {
-    scrollRestore(url);
+  ["DOMContentLoaded", "pageshow", "hashchange"].forEach(function (event) {
+    self.addEventListener(event, function (event) {
+      if (event.type === "pageshow") {
+        return event.persisted && self.scrollTo(0, settings["pager"][url]);
+      }
+      scrollRestore(url);
+    });
   });
 
   ["click", "touchstart", "scroll"].forEach(function (event) {