LibJS: Implement the Temporal.PlainDate constructor

And the simple Temporal.PlainDate.prototype getters, so that the
constructed Temporal.PlainDate may actually be validated.

Libraries/LibJS/Runtime/Intrinsics.cpp

@@ -101,6 +101,8 @@
 #include <LibJS/Runtime/SymbolPrototype.h>
 #include <LibJS/Runtime/Temporal/DurationConstructor.h>
 #include <LibJS/Runtime/Temporal/DurationPrototype.h>
+#include <LibJS/Runtime/Temporal/PlainDateConstructor.h>
+#include <LibJS/Runtime/Temporal/PlainDatePrototype.h>
 #include <LibJS/Runtime/Temporal/PlainMonthDayConstructor.h>
 #include <LibJS/Runtime/Temporal/PlainMonthDayPrototype.h>
 #include <LibJS/Runtime/Temporal/PlainYearMonthConstructor.h>

Libraries/LibJS/Runtime/Temporal/PlainDate.cpp

@@ -8,14 +8,26 @@
  */
 
 #include <AK/Checked.h>
+#include <LibJS/Runtime/AbstractOperations.h>
 #include <LibJS/Runtime/Temporal/Calendar.h>
 #include <LibJS/Runtime/Temporal/DateEquations.h>
 #include <LibJS/Runtime/Temporal/PlainDate.h>
+#include <LibJS/Runtime/Temporal/PlainDateConstructor.h>
 #include <LibJS/Runtime/Temporal/PlainDateTime.h>
 #include <LibJS/Runtime/Temporal/PlainTime.h>
 
 namespace JS::Temporal {
 
+GC_DEFINE_ALLOCATOR(PlainDate);
+
+// 3 Temporal.PlainDate Objects, https://tc39.es/proposal-temporal/#sec-temporal-plaindate-objects
+PlainDate::PlainDate(ISODate iso_date, String calendar, Object& prototype)
+    : Object(ConstructWithPrototypeTag::Tag, prototype)
+    , m_iso_date(iso_date)
+    , m_calendar(move(calendar))
+{
+}
+
 // 3.5.2 CreateISODateRecord ( year, month, day ), https://tc39.es/proposal-temporal/#sec-temporal-create-iso-date-record
 ISODate create_iso_date_record(double year, double month, double day)
 {
@@ -26,6 +38,106 @@ ISODate create_iso_date_record(double year, double month, double day)
     return { .year = static_cast<i32>(year), .month = static_cast<u8>(month), .day = static_cast<u8>(day) };
 }
 
+// 3.5.3 CreateTemporalDate ( isoDate, calendar [ , newTarget ] ), https://tc39.es/proposal-temporal/#sec-temporal-createtemporaldate
+ThrowCompletionOr<GC::Ref<PlainDate>> create_temporal_date(VM& vm, ISODate iso_date, String calendar, GC::Ptr<FunctionObject> new_target)
+{
+    auto& realm = *vm.current_realm();
+
+    // 1. If ISODateWithinLimits(isoDate) is false, throw a RangeError exception.
+    if (!iso_date_within_limits(iso_date))
+        return vm.throw_completion<RangeError>(ErrorType::TemporalInvalidPlainDate);
+
+    // 2. If newTarget is not present, set newTarget to %Temporal.PlainDate%.
+    if (!new_target)
+        new_target = realm.intrinsics().temporal_plain_date_constructor();
+
+    // 3. Let object be ? OrdinaryCreateFromConstructor(newTarget, "%Temporal.PlainDate.prototype%", « [[InitializedTemporalDate]], [[ISODate]], [[Calendar]] »).
+    // 4. Set object.[[ISODate]] to isoDate.
+    // 5. Set object.[[Calendar]] to calendar.
+    auto object = TRY(ordinary_create_from_constructor<PlainDate>(vm, *new_target, &Intrinsics::temporal_plain_date_prototype, iso_date, move(calendar)));
+
+    // 6. Return object.
+    return object;
+}
+
+// 3.5.4 ToTemporalDate ( item [ , options ] ), https://tc39.es/proposal-temporal/#sec-temporal-totemporaldate
+ThrowCompletionOr<GC::Ref<PlainDate>> to_temporal_date(VM& vm, Value item, Value options)
+{
+    // 1. If options is not present, set options to undefined.
+
+    // 2. If item is an Object, then
+    if (item.is_object()) {
+        auto const& object = item.as_object();
+
+        // a. If item has an [[InitializedTemporalDate]] internal slot, then
+        if (is<PlainDate>(object)) {
+            auto const& plain_date = static_cast<PlainDate const&>(object);
+
+            // i. Let resolvedOptions be ? GetOptionsObject(options).
+            auto resolved_options = TRY(get_options_object(vm, options));
+
+            // ii. Perform ? GetTemporalOverflowOption(resolvedOptions).
+            TRY(get_temporal_overflow_option(vm, resolved_options));
+
+            // iii. Return ! CreateTemporalDate(item.[[ISODate]], item.[[Calendar]]).
+            return MUST(create_temporal_date(vm, plain_date.iso_date(), plain_date.calendar()));
+        }
+        // FIXME: b. If item has an [[InitializedTemporalZonedDateTime]] internal slot, then
+        // FIXME:        i. Let isoDateTime be GetISODateTimeFor(item.[[TimeZone]], item.[[EpochNanoseconds]]).
+        // FIXME:        ii. Let resolvedOptions be ? GetOptionsObject(options).
+        // FIXME:        iii. Perform ? GetTemporalOverflowOption(resolvedOptions).
+        // FIXME:        iv. Return ! CreateTemporalDate(isoDateTime.[[ISODate]], item.[[Calendar]]).
+        // FIXME: c. If item has an [[InitializedTemporalDateTime]] internal slot, then
+        // FIXME:        i. Let resolvedOptions be ? GetOptionsObject(options).
+        // FIXME:        ii. Perform ? GetTemporalOverflowOption(resolvedOptions).
+        // FIXME:        iii. Return ! CreateTemporalDate(item.[[ISODateTime]].[[ISODate]], item.[[Calendar]]).
+
+        // d. Let calendar be ? GetTemporalCalendarIdentifierWithISODefault(item).
+        auto calendar = TRY(get_temporal_calendar_identifier_with_iso_default(vm, object));
+
+        // e. Let fields be ? PrepareCalendarFields(calendar, item, « YEAR, MONTH, MONTH-CODE, DAY », «», «»).
+        auto fields = TRY(prepare_calendar_fields(vm, calendar, object, { { CalendarField::Year, CalendarField::Month, CalendarField::MonthCode, CalendarField::Day } }, {}, CalendarFieldList {}));
+
+        // f. Let resolvedOptions be ? GetOptionsObject(options).
+        auto resolved_options = TRY(get_options_object(vm, options));
+
+        // g. Let overflow be ? GetTemporalOverflowOption(resolvedOptions).
+        auto overflow = TRY(get_temporal_overflow_option(vm, resolved_options));
+
+        // h. Let isoDate be ? CalendarDateFromFields(calendar, fields, overflow).
+        auto iso_date = TRY(calendar_date_from_fields(vm, calendar, move(fields), overflow));
+
+        // i. Return ! CreateTemporalDate(isoDate, calendar).
+        return MUST(create_temporal_date(vm, iso_date, move(calendar)));
+    }
+
+    // 3. If item is not a String, throw a TypeError exception.
+    if (!item.is_string())
+        return vm.throw_completion<TypeError>(ErrorType::TemporalInvalidPlainDate);
+
+    // 4. Let result be ? ParseISODateTime(item, « TemporalDateTimeString[~Zoned] »).
+    auto result = TRY(parse_iso_date_time(vm, item.as_string().utf8_string_view(), { { Production::TemporalDateTimeString } }));
+
+    // 5. Let calendar be result.[[Calendar]].
+    // 6. If calendar is empty, set calendar to "iso8601".
+    auto calendar = result.calendar.value_or("iso8601"_string);
+
+    // 7. Set calendar to ? CanonicalizeCalendar(calendar).
+    calendar = TRY(canonicalize_calendar(vm, calendar));
+
+    // 8. Let resolvedOptions be ? GetOptionsObject(options).
+    auto resolved_options = TRY(get_options_object(vm, options));
+
+    // 9. Perform ? GetTemporalOverflowOption(resolvedOptions).
+    TRY(get_temporal_overflow_option(vm, resolved_options));
+
+    // 10. Let isoDate be CreateISODateRecord(result.[[Year]], result.[[Month]], result.[[Day]]).
+    auto iso_date = create_iso_date_record(*result.year, result.month, result.day);
+
+    // 11. Return ? CreateTemporalDate(isoDate, calendar).
+    return TRY(create_temporal_date(vm, iso_date, move(calendar)));
+}
+
 // 3.5.5 ISODateSurpasses ( sign, y1, m1, d1, isoDate2 ), https://tc39.es/proposal-temporal/#sec-temporal-isodatesurpasses
 bool iso_date_surpasses(i8 sign, double year1, double month1, double day1, ISODate iso_date2)
 {

Libraries/LibJS/Runtime/Temporal/PlainDate.h

@@ -11,6 +11,7 @@
 
 #include <AK/Types.h>
 #include <LibJS/Runtime/Completion.h>
+#include <LibJS/Runtime/Object.h>
 #include <LibJS/Runtime/Temporal/AbstractOperations.h>
 
 namespace JS::Temporal {
@@ -22,7 +23,26 @@ struct ISODate {
     u8 day { 0 };
 };
 
+class PlainDate final : public Object {
+    JS_OBJECT(PlainDate, Object);
+    GC_DECLARE_ALLOCATOR(PlainDate);
+
+public:
+    virtual ~PlainDate() override = default;
+
+    [[nodiscard]] ISODate iso_date() const { return m_iso_date; }
+    [[nodiscard]] String const& calendar() const { return m_calendar; }
+
+private:
+    PlainDate(ISODate, String calendar, Object& prototype);
+
+    ISODate m_iso_date; // [[ISODate]]
+    String m_calendar;  // [[Calendar]]
+};
+
 ISODate create_iso_date_record(double year, double month, double day);
+ThrowCompletionOr<GC::Ref<PlainDate>> to_temporal_date(VM& vm, Value item, Value options = js_undefined());
+ThrowCompletionOr<GC::Ref<PlainDate>> create_temporal_date(VM&, ISODate, String calendar, GC::Ptr<FunctionObject> new_target = {});
 bool iso_date_surpasses(i8 sign, double year1, double month1, double day1, ISODate iso_date2);
 ThrowCompletionOr<ISODate> regulate_iso_date(VM& vm, double year, double month, double day, Overflow overflow);
 bool is_valid_iso_date(double year, double month, double day);

Libraries/LibJS/Runtime/Temporal/PlainDateConstructor.cpp

@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
+ * Copyright (c) 2024, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/Temporal/Calendar.h>
+#include <LibJS/Runtime/Temporal/PlainDate.h>
+#include <LibJS/Runtime/Temporal/PlainDateConstructor.h>
+
+namespace JS::Temporal {
+
+GC_DEFINE_ALLOCATOR(PlainDateConstructor);
+
+// 3.1 The Temporal.PlainDate Constructor, https://tc39.es/proposal-temporal/#sec-temporal-plaindate-constructor
+PlainDateConstructor::PlainDateConstructor(Realm& realm)
+    : NativeFunction(realm.vm().names.PlainDate.as_string(), realm.intrinsics().function_prototype())
+{
+}
+
+void PlainDateConstructor::initialize(Realm& realm)
+{
+    Base::initialize(realm);
+
+    auto& vm = this->vm();
+
+    // 3.2.1 Temporal.PlainDate.prototype, https://tc39.es/proposal-temporal/#sec-temporal.plaindate.prototype
+    define_direct_property(vm.names.prototype, realm.intrinsics().temporal_plain_date_prototype(), 0);
+
+    u8 attr = Attribute::Writable | Attribute::Configurable;
+    define_native_function(realm, vm.names.from, from, 1, attr);
+    define_native_function(realm, vm.names.compare, compare, 2, attr);
+
+    define_direct_property(vm.names.length, Value(3), Attribute::Configurable);
+}
+
+// 3.1.1 Temporal.PlainDate ( isoYear, isoMonth, isoDay [ , calendar ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaindate
+ThrowCompletionOr<Value> PlainDateConstructor::call()
+{
+    auto& vm = this->vm();
+
+    // 1. If NewTarget is undefined, throw a TypeError exception.
+    return vm.throw_completion<TypeError>(ErrorType::ConstructorWithoutNew, "Temporal.PlainDate");
+}
+
+// 3.1.1 Temporal.PlainDate ( isoYear, isoMonth, isoDay [ , calendar ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaindate
+ThrowCompletionOr<GC::Ref<Object>> PlainDateConstructor::construct(FunctionObject& new_target)
+{
+    auto& vm = this->vm();
+
+    auto iso_year = vm.argument(0);
+    auto iso_month = vm.argument(1);
+    auto iso_day = vm.argument(2);
+    auto calendar_value = vm.argument(3);
+
+    // 2. Let y be ? ToIntegerWithTruncation(isoYear).
+    auto year = TRY(to_integer_with_truncation(vm, iso_year, ErrorType::TemporalInvalidPlainDate));
+
+    // 3. Let m be ? ToIntegerWithTruncation(isoMonth).
+    auto month = TRY(to_integer_with_truncation(vm, iso_month, ErrorType::TemporalInvalidPlainDate));
+
+    // 4. Let d be ? ToIntegerWithTruncation(isoDay).
+    auto day = TRY(to_integer_with_truncation(vm, iso_day, ErrorType::TemporalInvalidPlainDate));
+
+    // 5. If calendar is undefined, set calendar to "iso8601".
+    if (calendar_value.is_undefined())
+        calendar_value = PrimitiveString::create(vm, "iso8601"_string);
+
+    // 6. If calendar is not a String, throw a TypeError exception.
+    if (!calendar_value.is_string())
+        return vm.throw_completion<TypeError>(ErrorType::NotAString, "calendar"sv);
+
+    // 7. Set calendar to ? CanonicalizeCalendar(calendar).
+    auto calendar = TRY(canonicalize_calendar(vm, calendar_value.as_string().utf8_string_view()));
+
+    // 8. If IsValidISODate(y, m, d) is false, throw a RangeError exception.
+    if (!is_valid_iso_date(year, month, day))
+        return vm.throw_completion<RangeError>(ErrorType::TemporalInvalidPlainDate);
+
+    // 9. Let isoDate be CreateISODateRecord(y, m, d).
+    auto iso_date = create_iso_date_record(year, month, day);
+
+    // 10. Return ? CreateTemporalDate(isoDate, calendar, NewTarget).
+    return TRY(create_temporal_date(vm, iso_date, move(calendar), &new_target));
+}
+
+// 3.2.2 3.2.2 Temporal.PlainDate.from ( item [ , options ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaindate.from
+JS_DEFINE_NATIVE_FUNCTION(PlainDateConstructor::from)
+{
+    // 1. Return ? ToTemporalDate(item, options).
+    return TRY(to_temporal_date(vm, vm.argument(0), vm.argument(1)));
+}
+
+// 3.2.3 Temporal.PlainDate.compare ( one, two ), https://tc39.es/proposal-temporal/#sec-temporal.plaindate.compare
+JS_DEFINE_NATIVE_FUNCTION(PlainDateConstructor::compare)
+{
+    // 1. Set one to ? ToTemporalDate(one).
+    auto one = TRY(to_temporal_date(vm, vm.argument(0)));
+
+    // 2. Set two to ? ToTemporalDate(two).
+    auto two = TRY(to_temporal_date(vm, vm.argument(1)));
+
+    // 3. Return 𝔽(CompareISODate(one.[[ISODate]], two.[[ISODate]])).
+    return compare_iso_date(one->iso_date(), two->iso_date());
+}
+
+}

Libraries/LibJS/Runtime/Temporal/PlainDateConstructor.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
+ * Copyright (c) 2024, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibJS/Runtime/NativeFunction.h>
+
+namespace JS::Temporal {
+
+class PlainDateConstructor final : public NativeFunction {
+    JS_OBJECT(PlainDateConstructor, NativeFunction);
+    GC_DECLARE_ALLOCATOR(PlainDateConstructor);
+
+public:
+    virtual void initialize(Realm&) override;
+    virtual ~PlainDateConstructor() override = default;
+
+    virtual ThrowCompletionOr<Value> call() override;
+    virtual ThrowCompletionOr<GC::Ref<Object>> construct(FunctionObject& new_target) override;
+
+private:
+    explicit PlainDateConstructor(Realm&);
+
+    virtual bool has_constructor() const override { return true; }
+
+    JS_DECLARE_NATIVE_FUNCTION(from);
+    JS_DECLARE_NATIVE_FUNCTION(compare);
+};
+
+}

Libraries/LibJS/Runtime/Temporal/PlainDatePrototype.cpp

@@ -0,0 +1,177 @@
+/*
+ * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
+ * Copyright (c) 2021-2023, Linus Groh <linusg@serenityos.org>
+ * Copyright (c) 2024, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/Temporal/Calendar.h>
+#include <LibJS/Runtime/Temporal/PlainDatePrototype.h>
+
+namespace JS::Temporal {
+
+GC_DEFINE_ALLOCATOR(PlainDatePrototype);
+
+// 3.3 Properties of the Temporal.PlainDate Prototype Object, https://tc39.es/proposal-temporal/#sec-properties-of-the-temporal-plaindate-prototype-object
+PlainDatePrototype::PlainDatePrototype(Realm& realm)
+    : PrototypeObject(realm.intrinsics().object_prototype())
+{
+}
+
+void PlainDatePrototype::initialize(Realm& realm)
+{
+    Base::initialize(realm);
+
+    auto& vm = this->vm();
+
+    // 3.3.2 Temporal.PlainDate.prototype[ %Symbol.toStringTag% ], https://tc39.es/proposal-temporal/#sec-temporal.plaindate.prototype-%symbol.tostringtag%
+    define_direct_property(vm.well_known_symbol_to_string_tag(), PrimitiveString::create(vm, "Temporal.PlainDate"_string), Attribute::Configurable);
+
+    define_native_accessor(realm, vm.names.calendarId, calendar_id_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.era, era_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.eraYear, era_year_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.year, year_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.month, month_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.monthCode, month_code_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.day, day_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.dayOfWeek, day_of_week_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.dayOfYear, day_of_year_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.weekOfYear, week_of_year_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.yearOfWeek, year_of_week_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.daysInWeek, days_in_week_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.daysInMonth, days_in_month_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.daysInYear, days_in_year_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.monthsInYear, months_in_year_getter, {}, Attribute::Configurable);
+    define_native_accessor(realm, vm.names.inLeapYear, in_leap_year_getter, {}, Attribute::Configurable);
+}
+
+// 3.3.3 get Temporal.PlainDate.prototype.calendarId, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.calendarid
+JS_DEFINE_NATIVE_FUNCTION(PlainDatePrototype::calendar_id_getter)
+{
+    // 1. Let temporalDate be the this value.
+    // 2. Perform ? RequireInternalSlot(temporalDate, [[InitializedTemporalDate]]).
+    auto temporal_date = TRY(typed_this_object(vm));
+
+    // 3. Return temporalDate.[[Calendar]].
+    return PrimitiveString::create(vm, temporal_date->calendar());
+}
+
+// 3.3.4 get Temporal.PlainDate.prototype.era, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.era
+JS_DEFINE_NATIVE_FUNCTION(PlainDatePrototype::era_getter)
+{
+    // 1. Let plainDate be the this value.
+    // 2. Perform ? RequireInternalSlot(plainDate, [[InitializedTemporalDate]]).
+    auto plain_date = TRY(typed_this_object(vm));
+
+    // 3. Return CalendarISOToDate(plainDate.[[Calendar]], plainDate.[[ISODate]]).[[Era]].
+    auto result = calendar_iso_to_date(plain_date->calendar(), plain_date->iso_date()).era;
+
+    if (!result.has_value())
+        return js_undefined();
+
+    return PrimitiveString::create(vm, result.release_value());
+}
+
+// 3.3.5 get Temporal.PlainDate.prototype.eraYear, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.erayear
+JS_DEFINE_NATIVE_FUNCTION(PlainDatePrototype::era_year_getter)
+{
+    // 1. Let plainDate be the this value.
+    // 2. Perform ? RequireInternalSlot(plainDate, [[InitializedTemporalDate]]).
+    auto plain_date = TRY(typed_this_object(vm));
+
+    // 3. Let result be CalendarISOToDate(plainDate.[[Calendar]], plainDate.[[ISODate]]).[[EraYear]].
+    auto result = calendar_iso_to_date(plain_date->calendar(), plain_date->iso_date()).era_year;
+
+    // 4. If result is undefined, return undefined.
+    if (!result.has_value())
+        return js_undefined();
+
+    // 5. Return 𝔽(result).
+    return *result;
+}
+
+// 3.3.6 get Temporal.PlainDate.prototype.year, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.year
+// 3.3.7 get Temporal.PlainDate.prototype.month, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.month
+// 3.3.9 get Temporal.PlainDate.prototype.day, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.day
+// 3.3.10 get Temporal.PlainDate.prototype.dayOfWeek, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.dayofweek
+// 3.3.11 get Temporal.PlainDate.prototype.dayOfYear, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.dayofyear
+// 3.3.14 get Temporal.PlainDate.prototype.daysInWeek, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.daysinweek
+// 3.3.15 get Temporal.PlainDate.prototype.daysInMonth, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.daysinmonth
+// 3.3.16 get Temporal.PlainDate.prototype.daysInYear, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.daysinyear
+// 3.3.17 get Temporal.PlainDate.prototype.monthsInYear, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.monthsinyear
+// 3.3.18 get Temporal.PlainDate.prototype.inLeapYear, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.inleapyear
+#define JS_ENUMERATE_PLAIN_DATE_SIMPLE_FIELDS \
+    __JS_ENUMERATE(year)                      \
+    __JS_ENUMERATE(month)                     \
+    __JS_ENUMERATE(day)                       \
+    __JS_ENUMERATE(day_of_week)               \
+    __JS_ENUMERATE(day_of_year)               \
+    __JS_ENUMERATE(days_in_week)              \
+    __JS_ENUMERATE(days_in_month)             \
+    __JS_ENUMERATE(days_in_year)              \
+    __JS_ENUMERATE(months_in_year)            \
+    __JS_ENUMERATE(in_leap_year)
+
+#define __JS_ENUMERATE(field)                                                                               \
+    JS_DEFINE_NATIVE_FUNCTION(PlainDatePrototype::field##_getter)                                           \
+    {                                                                                                       \
+        /* 1. Let temporalDate be the this value. */                                                        \
+        /* 2. Perform ? RequireInternalSlot(temporalDate, [[InitializedTemporalDate]]). */                  \
+        auto temporal_date = TRY(typed_this_object(vm));                                                    \
+                                                                                                            \
+        /* 3. Return CalendarISOToDate(temporalDate.[[Calendar]], temporalDate.[[ISODate]]).[[<field>]]. */ \
+        return calendar_iso_to_date(temporal_date->calendar(), temporal_date->iso_date()).field;            \
+    }
+JS_ENUMERATE_PLAIN_DATE_SIMPLE_FIELDS
+#undef __JS_ENUMERATE
+
+// 3.3.8 get Temporal.PlainDate.prototype.monthCode, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.monthcode
+JS_DEFINE_NATIVE_FUNCTION(PlainDatePrototype::month_code_getter)
+{
+    // 1. Let temporalDate be the this value.
+    // 2. Perform ? RequireInternalSlot(temporalDate, [[InitializedTemporalDate]]).
+    auto temporal_date = TRY(typed_this_object(vm));
+
+    // 3. Return CalendarISOToDate(temporalDate.[[Calendar]], temporalDate.[[ISODate]]).[[MonthCode]].
+    auto month_code = calendar_iso_to_date(temporal_date->calendar(), temporal_date->iso_date()).month_code;
+    return PrimitiveString::create(vm, move(month_code));
+}
+
+// 3.3.12 get Temporal.PlainDate.prototype.weekOfYear, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.weekofyear
+JS_DEFINE_NATIVE_FUNCTION(PlainDatePrototype::week_of_year_getter)
+{
+    // 1. Let temporalDate be the this value.
+    // 2. Perform ? RequireInternalSlot(temporalDate, [[InitializedTemporalDate]]).
+    auto temporal_date = TRY(typed_this_object(vm));
+
+    // 3. Let result be CalendarISOToDate(temporalDate.[[Calendar]], temporalDate.[[ISODate]]).[[WeekOfYear]].[[Week]].
+    auto result = calendar_iso_to_date(temporal_date->calendar(), temporal_date->iso_date()).week_of_year.week;
+
+    // 4. If result is undefined, return undefined.
+    if (!result.has_value())
+        return js_undefined();
+
+    // 5. Return 𝔽(result).
+    return *result;
+}
+
+// 3.3.13 get Temporal.PlainDate.prototype.yearOfWeek, https://tc39.es/proposal-temporal/#sec-get-temporal.plaindate.prototype.yearofweek
+JS_DEFINE_NATIVE_FUNCTION(PlainDatePrototype::year_of_week_getter)
+{
+    // 1. Let temporalDate be the this value.
+    // 2. Perform ? RequireInternalSlot(temporalDate, [[InitializedTemporalDate]]).
+    auto temporal_date = TRY(typed_this_object(vm));
+
+    // 3. Let result be CalendarISOToDate(temporalDate.[[Calendar]], temporalDate.[[ISODate]]).[[WeekOfYear]].[[Year]].
+    auto result = calendar_iso_to_date(temporal_date->calendar(), temporal_date->iso_date()).week_of_year.year;
+
+    // 4. If result is undefined, return undefined.
+    if (!result.has_value())
+        return js_undefined();
+
+    // 5. Return 𝔽(result).
+    return *result;
+}
+
+}

Libraries/LibJS/Runtime/Temporal/PlainDatePrototype.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
+ * Copyright (c) 2024, Tim Flynn <trflynn89@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibJS/Runtime/PrototypeObject.h>
+#include <LibJS/Runtime/Temporal/PlainDate.h>
+
+namespace JS::Temporal {
+
+class PlainDatePrototype final : public PrototypeObject<PlainDatePrototype, PlainDate> {
+    JS_PROTOTYPE_OBJECT(PlainDatePrototype, PlainDate, Temporal.PlainDate);
+    GC_DECLARE_ALLOCATOR(PlainDatePrototype);
+
+public:
+    virtual void initialize(Realm&) override;
+    virtual ~PlainDatePrototype() override = default;
+
+private:
+    explicit PlainDatePrototype(Realm&);
+
+    JS_DECLARE_NATIVE_FUNCTION(calendar_id_getter);
+    JS_DECLARE_NATIVE_FUNCTION(era_getter);
+    JS_DECLARE_NATIVE_FUNCTION(era_year_getter);
+    JS_DECLARE_NATIVE_FUNCTION(year_getter);
+    JS_DECLARE_NATIVE_FUNCTION(month_getter);
+    JS_DECLARE_NATIVE_FUNCTION(month_code_getter);
+    JS_DECLARE_NATIVE_FUNCTION(day_getter);
+    JS_DECLARE_NATIVE_FUNCTION(day_of_week_getter);
+    JS_DECLARE_NATIVE_FUNCTION(day_of_year_getter);
+    JS_DECLARE_NATIVE_FUNCTION(week_of_year_getter);
+    JS_DECLARE_NATIVE_FUNCTION(year_of_week_getter);
+    JS_DECLARE_NATIVE_FUNCTION(days_in_week_getter);
+    JS_DECLARE_NATIVE_FUNCTION(days_in_month_getter);
+    JS_DECLARE_NATIVE_FUNCTION(days_in_year_getter);
+    JS_DECLARE_NATIVE_FUNCTION(months_in_year_getter);
+    JS_DECLARE_NATIVE_FUNCTION(in_leap_year_getter);
+};
+
+}

Libraries/LibJS/Runtime/Temporal/Temporal.cpp

@@ -7,6 +7,7 @@
 
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/Temporal/DurationConstructor.h>
+#include <LibJS/Runtime/Temporal/PlainDateConstructor.h>
 #include <LibJS/Runtime/Temporal/PlainMonthDayConstructor.h>
 #include <LibJS/Runtime/Temporal/PlainYearMonthConstructor.h>
 #include <LibJS/Runtime/Temporal/Temporal.h>
@@ -32,6 +33,7 @@ void Temporal::initialize(Realm& realm)
 
     u8 attr = Attribute::Writable | Attribute::Configurable;
     define_intrinsic_accessor(vm.names.Duration, attr, [](auto& realm) -> Value { return realm.intrinsics().temporal_duration_constructor(); });
+    define_intrinsic_accessor(vm.names.PlainDate, attr, [](auto& realm) -> Value { return realm.intrinsics().temporal_plain_date_constructor(); });
     define_intrinsic_accessor(vm.names.PlainMonthDay, attr, [](auto& realm) -> Value { return realm.intrinsics().temporal_plain_month_day_constructor(); });
     define_intrinsic_accessor(vm.names.PlainYearMonth, attr, [](auto& realm) -> Value { return realm.intrinsics().temporal_plain_year_month_constructor(); });
 }