diff --git a/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h b/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h
index 341a5591990..96b9808364c 100644
--- a/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h
+++ b/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h
@@ -93,6 +93,7 @@ namespace JS {
     P(byteLength)                            \
     P(byteOffset)                            \
     P(calendar)                              \
+    P(calendarId)                            \
     P(calendarName)                          \
     P(call)                                  \
     P(callee)                                \