From fe83d46e84b728bd374b4adddf1e1426c813e078 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Tue, 13 Apr 2021 18:41:07 +0800
Subject: ...

---
 .../utilities/useReverseScrollPositionRemember.ts  | 24 ++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

(limited to 'FrontEnd/src/app/utilities/useReverseScrollPositionRemember.ts')

diff --git a/FrontEnd/src/app/utilities/useReverseScrollPositionRemember.ts b/FrontEnd/src/app/utilities/useReverseScrollPositionRemember.ts
index 8a2bd7a0..67c7c458 100644
--- a/FrontEnd/src/app/utilities/useReverseScrollPositionRemember.ts
+++ b/FrontEnd/src/app/utilities/useReverseScrollPositionRemember.ts
@@ -7,19 +7,31 @@ export default function useReverseScrollPositionRemember(): void {
     if (on) return;
     on = true;
 
-    let scrollPosition =
-      document.documentElement.scrollHeight -
-      document.documentElement.scrollTop;
-
+    function getScrollPosition(): number {
+      if (document.documentElement.scrollHeight <= window.innerHeight) {
+        return 0;
+      } else {
+        return (
+          document.documentElement.scrollHeight -
+          document.documentElement.scrollTop -
+          window.innerHeight
+        );
+      }
+    }
+
+    let scrollPosition = getScrollPosition();
     const scrollListener = (): void => {
-      scrollPosition = document.documentElement.scrollHeight - window.scrollY;
+      scrollPosition = getScrollPosition();
     };
 
     window.addEventListener("scroll", scrollListener);
 
     const resizeObserver = new ResizeObserver(() => {
+      if (document.documentElement.scrollHeight <= window.innerHeight) return;
       document.documentElement.scrollTop =
-        document.documentElement.scrollHeight - scrollPosition;
+        document.documentElement.scrollHeight -
+        window.innerHeight -
+        scrollPosition;
     });
 
     resizeObserver.observe(document.documentElement);
-- 
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