2 files changed, 21 insertions, 0 deletions
diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/Now.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/Now.cpp
index f33e1c3529..5f702ad883 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/Now.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/Now.cpp
@@ -35,6 +35,7 @@ void Now::initialize(GlobalObject& global_object)
     define_native_function(vm.names.timeZone, time_zone, 0, attr);
     define_native_function(vm.names.instant, instant, 0, attr);
     define_native_function(vm.names.plainDate, plain_date, 1, attr);
+    define_native_function(vm.names.plainDateISO, plain_date_iso, 0, attr);
 }
 
 // 2.1.1 Temporal.Now.timeZone ( ), https://tc39.es/proposal-temporal/#sec-temporal.now.timezone
@@ -66,6 +67,25 @@ JS_DEFINE_NATIVE_FUNCTION(Now::plain_date)
     return create_temporal_date(global_object, date_time->iso_year(), date_time->iso_month(), date_time->iso_day(), date_time->calendar());
 }
 
+// 2.1.8 Temporal.Now.plainDateISO ( [ temporalTimeZoneLike ] ), https://tc39.es/proposal-temporal/#sec-temporal.now.plaindateiso
+JS_DEFINE_NATIVE_FUNCTION(Now::plain_date_iso)
+{
+    auto temporal_time_zone_like = vm.argument(0);
+
+    // 1. Let calendar be ? GetISO8601Calendar().
+    auto* calendar = get_iso8601_calendar(global_object);
+    if (vm.exception())
+        return {};
+
+    // 2. Let dateTime be ? SystemDateTime(temporalTimeZoneLike, calendar).
+    auto* date_time = system_date_time(global_object, temporal_time_zone_like, calendar);
+    if (vm.exception())
+        return {};
+
+    // 3. Return ? CreateTemporalDate(dateTime.[[ISOYear]], dateTime.[[ISOMonth]], dateTime.[[ISODay]], dateTime.[[Calendar]]).
+    return create_temporal_date(global_object, date_time->iso_year(), date_time->iso_month(), date_time->iso_day(), date_time->calendar());
+}
+
 // 2.2.1 SystemTimeZone ( ), https://tc39.es/proposal-temporal/#sec-temporal-systemtimezone
 TimeZone* system_time_zone(GlobalObject& global_object)
 {
diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/Now.h b/Userland/Libraries/LibJS/Runtime/Temporal/Now.h
index e22a44ee16..7d85c612bb 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/Now.h
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/Now.h
@@ -22,6 +22,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(time_zone);
     JS_DECLARE_NATIVE_FUNCTION(instant);
     JS_DECLARE_NATIVE_FUNCTION(plain_date);
+    JS_DECLARE_NATIVE_FUNCTION(plain_date_iso);
 };
 
 TimeZone* system_time_zone(GlobalObject&);