From 29ce643ac154656b7e7f3b3bf094c5ee4daa05c2 Mon Sep 17 00:00:00 2001
From: sstent <stuart.stent@gmail.com>
Date: Sat, 21 Feb 2026 09:35:52 -0800
Subject: [PATCH] fix(icalendar): Add workweekstart to RRULE key map

---
 icalendar.ts                |  1 +
 test_data/outlook_repro.ics | 11 +++++++++++
 2 files changed, 12 insertions(+)
 create mode 100644 test_data/outlook_repro.ics

diff --git a/icalendar.ts b/icalendar.ts
index b8e0811..ba577fe 100644
--- a/icalendar.ts
+++ b/icalendar.ts
@@ -26,6 +26,7 @@ const RRULE_KEY_MAP: Record<string, string> = {
   "bymonth": "BYMONTH",
   "bysetpos": "BYSETPOS",
   "wkst": "WKST",
+  "workweekstart": "WKST",
   "freq": "FREQ", // Just in case
 };
 
diff --git a/test_data/outlook_repro.ics b/test_data/outlook_repro.ics
new file mode 100644
index 0000000..d9ec6a7
--- /dev/null
+++ b/test_data/outlook_repro.ics
@@ -0,0 +1,11 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//Repro//EN
+BEGIN:VEVENT
+UID:repro-workweekstart
+SUMMARY:Repro WorkWeekStart
+DTSTART:20260219T100000Z
+DTEND:20260219T110000Z
+RRULE:FREQ=WEEKLY;BYDAY=MO;WKST=MO
+END:VEVENT
+END:VCALENDAR