LibJS: Implement Temporal.PlainMonthDay.prototype.valueOf

Libraries/LibJS/Runtime/Temporal/PlainMonthDayPrototype.cpp

@@ -40,6 +40,7 @@ void PlainMonthDayPrototype::initialize(Realm& realm)
     define_native_function(realm, vm.names.toString, to_string, 0, attr);
     define_native_function(realm, vm.names.toLocaleString, to_locale_string, 0, attr);
     define_native_function(realm, vm.names.toJSON, to_json, 0, attr);
+    define_native_function(realm, vm.names.valueOf, value_of, 0, attr);
 }
 
 // 10.3.3 get Temporal.PlainMonthDay.prototype.calendarId, https://tc39.es/proposal-temporal/#sec-get-temporal.plainmonthday.prototype.calendarid
@@ -172,4 +173,11 @@ JS_DEFINE_NATIVE_FUNCTION(PlainMonthDayPrototype::to_json)
     return PrimitiveString::create(vm, temporal_month_day_to_string(month_day, ShowCalendar::Auto));
 }
 
+// 10.3.11 Temporal.PlainMonthDay.prototype.valueOf ( ), https://tc39.es/proposal-temporal/#sec-temporal.plainmonthday.prototype.valueof
+JS_DEFINE_NATIVE_FUNCTION(PlainMonthDayPrototype::value_of)
+{
+    // 1. Throw a TypeError exception.
+    return vm.throw_completion<TypeError>(ErrorType::Convert, "Temporal.PlainMonthDay", "a primitive value");
+}
+
 }

Libraries/LibJS/Runtime/Temporal/PlainMonthDayPrototype.h

@@ -31,6 +31,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(to_string);
     JS_DECLARE_NATIVE_FUNCTION(to_locale_string);
     JS_DECLARE_NATIVE_FUNCTION(to_json);
+    JS_DECLARE_NATIVE_FUNCTION(value_of);
 };
 
 }

Libraries/LibJS/Tests/builtins/Temporal/PlainMonthDay/PlainMonthDay.prototype.valueOf.js

@@ -0,0 +1,11 @@
+describe("errors", () => {
+    test("throws TypeError", () => {
+        const plainMonthDay = new Temporal.PlainMonthDay(7, 6);
+        expect(() => {
+            plainMonthDay.valueOf();
+        }).toThrowWithMessage(
+            TypeError,
+            "Cannot convert Temporal.PlainMonthDay to a primitive value"
+        );
+    });
+});