LibJS: Implement Temporal.PlainMonthDay.prototype.getISOFields()

Userland/Libraries/LibJS/Runtime/Temporal/PlainMonthDayPrototype.cpp

@@ -33,6 +33,7 @@ void PlainMonthDayPrototype::initialize(GlobalObject& global_object)
 
     u8 attr = Attribute::Writable | Attribute::Configurable;
     define_native_function(vm.names.valueOf, value_of, 0, attr);
+    define_native_function(vm.names.getISOFields, get_iso_fields, 0, attr);
 }
 
 static PlainMonthDay* typed_this(GlobalObject& global_object)
@@ -101,4 +102,32 @@ JS_DEFINE_NATIVE_FUNCTION(PlainMonthDayPrototype::value_of)
     return {};
 }
 
+// 10.3.13 Temporal.PlainMonthDay.prototype.getISOFields ( ), https://tc39.es/proposal-temporal/#sec-temporal.plainmonthday.prototype.getisofields
+JS_DEFINE_NATIVE_FUNCTION(PlainMonthDayPrototype::get_iso_fields)
+{
+    // 1. Let monthDay be the this value.
+    // 2. Perform ? RequireInternalSlot(monthDay, [[InitializedTemporalMonthDay]]).
+    auto* month_day = typed_this(global_object);
+    if (vm.exception())
+        return {};
+
+    // 3. Let fields be ! OrdinaryObjectCreate(%Object.prototype%).
+    auto* fields = Object::create(global_object, global_object.object_prototype());
+
+    // 4. Perform ! CreateDataPropertyOrThrow(fields, "calendar", monthDay.[[Calendar]]).
+    fields->create_data_property_or_throw(vm.names.calendar, Value(&month_day->calendar()));
+
+    // 5. Perform ! CreateDataPropertyOrThrow(fields, "isoDay", 𝔽(monthDay.[[ISODay]])).
+    fields->create_data_property_or_throw(vm.names.isoDay, Value(month_day->iso_day()));
+
+    // 6. Perform ! CreateDataPropertyOrThrow(fields, "isoMonth", 𝔽(monthDay.[[ISOMonth]])).
+    fields->create_data_property_or_throw(vm.names.isoMonth, Value(month_day->iso_month()));
+
+    // 7. Perform ! CreateDataPropertyOrThrow(fields, "isoYear", 𝔽(monthDay.[[ISOYear]])).
+    fields->create_data_property_or_throw(vm.names.isoYear, Value(month_day->iso_year()));
+
+    // 8. Return fields.
+    return fields;
+}
+
 }

Userland/Libraries/LibJS/Runtime/Temporal/PlainMonthDayPrototype.h

@@ -23,6 +23,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(month_code_getter);
     JS_DECLARE_NATIVE_FUNCTION(day_getter);
     JS_DECLARE_NATIVE_FUNCTION(value_of);
+    JS_DECLARE_NATIVE_FUNCTION(get_iso_fields);
 };
 
 }

Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainMonthDay/PlainMonthDay.prototype.getISOFields.js

@@ -0,0 +1,27 @@
+describe("normal behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.PlainMonthDay.prototype.getISOFields).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        const calendar = new Temporal.Calendar("iso8601");
+        const plainMonthDay = new Temporal.PlainMonthDay(7, 6, calendar, 2021);
+        const fields = plainMonthDay.getISOFields();
+        expect(fields).toEqual({ calendar, isoDay: 6, isoMonth: 7, isoYear: 2021 });
+        // Test field order
+        expect(Object.getOwnPropertyNames(fields)).toEqual([
+            "calendar",
+            "isoDay",
+            "isoMonth",
+            "isoYear",
+        ]);
+    });
+});
+
+describe("errors", () => {
+    test("this value must be a Temporal.PlainMonthDay object", () => {
+        expect(() => {
+            Temporal.PlainMonthDay.prototype.getISOFields.call("foo");
+        }).toThrowWithMessage(TypeError, "Not a Temporal.PlainMonthDay");
+    });
+});