LibJS: Implement Temporal.PlainMonthDay.prototype.equals

Author: https://github.com/Lubrsi
Commit: https://github.com/SerenityOS/serenity/commit/3548b08de2d
Pull-request: https://github.com/SerenityOS/serenity/pull/9926
Reviewed-by: https://github.com/linusg ✅

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

@@ -33,6 +33,7 @@ void PlainMonthDayPrototype::initialize(GlobalObject& global_object)
     define_native_accessor(vm.names.day, day_getter, {}, Attribute::Configurable);
 
     u8 attr = Attribute::Writable | Attribute::Configurable;
+    define_native_function(vm.names.equals, equals, 1, attr);
     define_native_function(vm.names.toString, to_string, 0, attr);
     define_native_function(vm.names.toLocaleString, to_locale_string, 0, attr);
     define_native_function(vm.names.toJSON, to_json, 0, attr);
@@ -98,6 +99,36 @@ JS_DEFINE_NATIVE_FUNCTION(PlainMonthDayPrototype::day_getter)
     return Value(calendar_day(global_object, calendar, *month_day));
 }
 
+// 10.3.7 Temporal.PlainMonthDay.prototype.equals ( other ), https://tc39.es/proposal-temporal/#sec-temporal.plainmonthday.prototype.equals
+JS_DEFINE_NATIVE_FUNCTION(PlainMonthDayPrototype::equals)
+{
+    // 1. Let monthDay be the this value.
+    // 2. Perform ? RequireInternalSlot(monthDay, [[InitializedTemporalMonthDay]]).
+    auto* month_day = typed_this(global_object);
+    if (vm.exception())
+        return {};
+
+    // 3. Set other to ? ToTemporalMonthDay(other).
+    auto* other = to_temporal_month_day(global_object, vm.argument(0));
+    if (vm.exception())
+        return {};
+
+    // 4. If monthDay.[[ISOMonth]] ≠ other.[[ISOMonth]], return false.
+    if (month_day->iso_month() != other->iso_month())
+        return Value(false);
+
+    // 5. If monthDay.[[ISODay]] ≠ other.[[ISODay]], return false.
+    if (month_day->iso_day() != other->iso_day())
+        return Value(false);
+
+    // 6. If monthDay.[[ISOYear]] ≠ other.[[ISOYear]], return false.
+    if (month_day->iso_year() != other->iso_year())
+        return Value(false);
+
+    // 7. Return ? CalendarEquals(monthDay.[[Calendar]], other.[[Calendar]]).
+    return Value(calendar_equals(global_object, month_day->calendar(), other->calendar()));
+}
+
 // 10.3.8 Temporal.PlainMonthDay.prototype.toString ( [ options ] ), https://tc39.es/proposal-temporal/#sec-temporal.plainmonthday.prototype.tostring
 JS_DEFINE_NATIVE_FUNCTION(PlainMonthDayPrototype::to_string)
 {

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

@@ -22,6 +22,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(calendar_getter);
     JS_DECLARE_NATIVE_FUNCTION(month_code_getter);
     JS_DECLARE_NATIVE_FUNCTION(day_getter);
+    JS_DECLARE_NATIVE_FUNCTION(equals);
     JS_DECLARE_NATIVE_FUNCTION(to_string);
     JS_DECLARE_NATIVE_FUNCTION(to_locale_string);
     JS_DECLARE_NATIVE_FUNCTION(to_json);

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

@@ -0,0 +1,15 @@
+describe("correct behavior", () => {
+    test("length is 1", () => {
+        expect(Temporal.PlainMonthDay.prototype.equals).toHaveLength(1);
+    });
+
+    test("basic functionality", () => {
+        const calendar = { hello: "friends" };
+        const firstPlainMonthDay = new Temporal.PlainMonthDay(2, 1, calendar);
+        const secondPlainMonthDay = new Temporal.PlainMonthDay(1, 1, calendar);
+        expect(firstPlainMonthDay.equals(firstPlainMonthDay)).toBeTrue();
+        expect(secondPlainMonthDay.equals(secondPlainMonthDay)).toBeTrue();
+        expect(firstPlainMonthDay.equals(secondPlainMonthDay)).toBeFalse();
+        expect(secondPlainMonthDay.equals(firstPlainMonthDay)).toBeFalse();
+    });
+});