From: Anton Khorev <tony29@yandex.ru>
Date: Sun, 16 Mar 2025 16:21:10 +0000 (+0300)
Subject: Preserve sidebar scroll position when prepending to history
X-Git-Tag: live~107^2
X-Git-Url: https://git.openstreetmap.org./rails.git/commitdiff_plain/9880953e9191777574141adfb4fa340589c5a7a4

Preserve sidebar scroll position when prepending to history
---

diff --git a/app/assets/javascripts/index/history.js b/app/assets/javascripts/index/history.js
index 4264e5dce..229fdc2b6 100644
--- a/app/assets/javascripts/index/history.js
+++ b/app/assets/javascripts/index/history.js
@@ -48,6 +48,9 @@ OSM.History = function (map) {
   }
 
   function displayMoreChangesets(div, html) {
+    const sidebar = $("#sidebar")[0];
+    const previousScrollHeightMinusTop = sidebar.scrollHeight - sidebar.scrollTop;
+
     const oldList = $("#sidebar_content .changesets ol");
 
     div.replaceWith(html);
@@ -57,6 +60,9 @@ OSM.History = function (map) {
       prevNewList.next(".changeset_more").remove();
       prevNewList.children().prependTo(oldList);
       prevNewList.remove();
+
+      // restore scroll position only if prepending
+      sidebar.scrollTop = sidebar.scrollHeight - previousScrollHeightMinusTop;
     }
 
     const nextNewList = oldList.nextAll("ol");