From e267bfeaa4f3c037287716538d9b5a325ae6d036 Mon Sep 17 00:00:00 2001
From: Anders Demant van der Weide <antra@antra.dk>
Date: Sat, 29 Aug 2026 08:39:03 +0200
Subject: [PATCH] Fix calendar title transform when regex does not match

---
 defaultmodules/calendar/calendarutils.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/defaultmodules/calendar/calendarutils.js b/defaultmodules/calendar/calendarutils.js
index 9b43de8503..9349c0666e 100644
--- a/defaultmodules/calendar/calendarutils.js
+++ b/defaultmodules/calendar/calendarutils.js
@@ -109,7 +109,7 @@ const CalendarUtils = {
 					let replacement = transform.replace;
 					if (typeof transform.yearmatchgroup !== "undefined" && transform.yearmatchgroup !== "") {
 						const yearmatch = [...title.matchAll(needle)];
-						if (yearmatch[0].length >= transform.yearmatchgroup + 1 && yearmatch[0][transform.yearmatchgroup] * 1 >= 1900) {
+						if (yearmatch.length > 0 && yearmatch[0].length >= transform.yearmatchgroup + 1 && yearmatch[0][transform.yearmatchgroup] * 1 >= 1900) {
 							let calcage = new Date().getFullYear() - yearmatch[0][transform.yearmatchgroup] * 1;
 							let searchstr = `$${transform.yearmatchgroup}`;
 							replacement = replacement.replace(searchstr, calcage);