From 540b607459d071e73d89a5050e59b882e9ebc696 Mon Sep 17 00:00:00 2001
From: Elian Doran <contact@eliandoran.me>
Date: Fri, 10 Apr 2026 20:13:00 +0300
Subject: [PATCH] fix(note_map): freezing the app if there are too many notes
 (closes #8916)

---
 .../src/translations/en/translation.json      |  3 ++-
 apps/client/src/widgets/note_map/NoteMap.css  |  4 ++--
 apps/client/src/widgets/note_map/NoteMap.tsx  | 19 +++++++++++++++++++
 3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/apps/client/src/translations/en/translation.json b/apps/client/src/translations/en/translation.json
index 6006d665e4..a080456435 100644
--- a/apps/client/src/translations/en/translation.json
+++ b/apps/client/src/translations/en/translation.json
@@ -860,7 +860,8 @@
     "collapse": "Collapse to normal size",
     "title": "Note Map",
     "fix-nodes": "Fix nodes",
-    "link-distance": "Link distance"
+    "link-distance": "Link distance",
+    "too-many-notes": "This subtree contains {{count}} notes, which exceeds the limit of {{max}} that can be displayed in the note map."
   },
   "note_paths": {
     "title": "Note Paths",
diff --git a/apps/client/src/widgets/note_map/NoteMap.css b/apps/client/src/widgets/note_map/NoteMap.css
index fa49bb39c6..3188f09439 100644
--- a/apps/client/src/widgets/note_map/NoteMap.css
+++ b/apps/client/src/widgets/note_map/NoteMap.css
@@ -1,5 +1,5 @@
 .note-detail-note-map {
-            height: 100%;
+    height: 100%;
     overflow: hidden;
 }
 
@@ -54,4 +54,4 @@
     width: 10px;
 }
 
-/* End of styling the slider */
\ No newline at end of file
+/* End of styling the slider */
diff --git a/apps/client/src/widgets/note_map/NoteMap.tsx b/apps/client/src/widgets/note_map/NoteMap.tsx
index 2677e4aa59..a165d467bb 100644
--- a/apps/client/src/widgets/note_map/NoteMap.tsx
+++ b/apps/client/src/widgets/note_map/NoteMap.tsx
@@ -12,11 +12,15 @@ import { t } from "../../services/i18n";
 import { getEffectiveThemeStyle } from "../../services/theme";
 import ActionButton from "../react/ActionButton";
 import { useElementSize, useNoteLabel } from "../react/hooks";
+import NoItems from "../react/NoItems";
 import Slider from "../react/Slider";
 import { loadNotesAndRelations, NoteMapLinkObject, NoteMapNodeObject, NotesAndRelationsData } from "./data";
 import { CssData, setupRendering } from "./rendering";
 import { MapType, NoteMapWidgetMode, rgb2hex } from "./utils";
 
+/** Maximum number of notes to render in the note map before showing a warning. */
+const MAX_NOTES_THRESHOLD = 1_000;
+
 interface NoteMapProps {
     note: FNote;
     widgetMode: NoteMapWidgetMode;
@@ -34,6 +38,7 @@ export default function NoteMap({ note, widgetMode, parentRef }: NoteMapProps) {
     const containerSize = useElementSize(parentRef);
     const [ fixNodes, setFixNodes ] = useState(false);
     const [ linkDistance, setLinkDistance ] = useState(40);
+    const [ tooManyNotes, setTooManyNotes ] = useState<number | null>(null);
     const notesAndRelationsRef = useRef<NotesAndRelationsData>();
 
     const mapRootId = useMemo(() => {
@@ -61,6 +66,14 @@ export default function NoteMap({ note, widgetMode, parentRef }: NoteMapProps) {
         const includeRelations = labelValues("mapIncludeRelation");
         loadNotesAndRelations(mapRootId, excludeRelations, includeRelations, mapType).then((notesAndRelations) => {
             if (!containerRef.current || !styleResolverRef.current) return;
+
+            // Guard against rendering too many notes which would freeze the browser.
+            if (notesAndRelations.nodes.length > MAX_NOTES_THRESHOLD) {
+                setTooManyNotes(notesAndRelations.nodes.length);
+                return;
+            }
+            setTooManyNotes(null);
+
             const cssData = getCssData(containerRef.current, styleResolverRef.current);
 
             // Configure rendering properties.
@@ -119,6 +132,12 @@ export default function NoteMap({ note, widgetMode, parentRef }: NoteMapProps) {
         });
     }, [ fixNodes, mapType ]);
 
+    if (tooManyNotes) {
+        return (
+            <NoItems icon="bx bx-error-circle" text={t("note_map.too-many-notes", { count: tooManyNotes, max: MAX_NOTES_THRESHOLD })} />
+        );
+    }
+
     return (
         <div className="note-map-widget">
             <div className="btn-group btn-group-sm map-type-switcher content-floating-buttons top-left" role="group">