LibJS: Implement the Temporal.PlainYearMonth constructor

And the simple Temporal.PlainYearMonth.prototype getters, so that the constructed Temporal.PlainYearMonth may actually be validated.
Author: https://github.com/trflynn89 Commit: b68d67693e Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2496
2025-08-09 09:39:39 +00:00 · 2024-11-21 11:22:32 -05:00 · 2024-11-21 11:22:32 -05:00 · b68d67693e · 2024-11-22 18:56:56 +00:00
commit b68d67693e
parent 1c733993e0
27 changed files with 926 additions and 3 deletions
--- a/Libraries/LibJS/Runtime/Temporal/PlainYearMonth.cpp
+++ b/Libraries/LibJS/Runtime/Temporal/PlainYearMonth.cpp
@ -0,0 +1,152 @@
+/*
+ * 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/AbstractOperations.h>
+#include <LibJS/Runtime/Intrinsics.h>
+#include <LibJS/Runtime/Realm.h>
+#include <LibJS/Runtime/Temporal/Calendar.h>
+#include <LibJS/Runtime/Temporal/PlainYearMonth.h>
+#include <LibJS/Runtime/Temporal/PlainYearMonthConstructor.h>
+#include <LibJS/Runtime/VM.h>
+
+namespace JS::Temporal {
+
+GC_DEFINE_ALLOCATOR(PlainYearMonth);
+
+// 9 Temporal.PlainYearMonth Objects, https://tc39.es/proposal-temporal/#sec-temporal-plainyearmonth-objects
+PlainYearMonth::PlainYearMonth(ISODate iso_date, String calendar, Object& prototype)
+    : Object(ConstructWithPrototypeTag::Tag, prototype)
+    , m_iso_date(iso_date)
+    , m_calendar(move(calendar))
+{
+}
+
+// 9.5.2 ToTemporalYearMonth ( item [ , options ] ), https://tc39.es/proposal-temporal/#sec-temporal-totemporalyearmonth
+ThrowCompletionOr<GC::Ref<PlainYearMonth>> to_temporal_year_month(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 [[InitializedTemporalYearMonth]] internal slot, then
+        if (is<PlainYearMonth>(object)) {
+            auto const& plain_year_month = static_cast<PlainYearMonth 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 ! CreateTemporalYearMonth(item.[[ISODate]], item.[[Calendar]]).
+            return MUST(create_temporal_year_month(vm, plain_year_month.iso_date(), plain_year_month.calendar()));
+        }
+
+        // b. Let calendar be ? GetTemporalCalendarIdentifierWithISODefault(item).
+        auto calendar = TRY(get_temporal_calendar_identifier_with_iso_default(vm, object));
+
+        // c. Let fields be ? PrepareCalendarFields(calendar, item, « YEAR, MONTH, MONTH-CODE », «», «»).
+        auto fields = TRY(prepare_calendar_fields(vm, calendar, object, { { CalendarField::Year, CalendarField::Month, CalendarField::MonthCode } }, {}, CalendarFieldList {}));
+
+        // d. Let resolvedOptions be ? GetOptionsObject(options).
+        auto resolved_options = TRY(get_options_object(vm, options));
+
+        // e. Let overflow be ? GetTemporalOverflowOption(resolvedOptions).
+        auto overflow = TRY(get_temporal_overflow_option(vm, resolved_options));
+
+        // f. Let isoDate be ? CalendarYearMonthFromFields(calendar, fields, overflow).
+        auto iso_date = TRY(calendar_year_month_from_fields(vm, calendar, move(fields), overflow));
+
+        // g. Return ! CreateTemporalYearMonth(isoDate, calendar).
+        return MUST(create_temporal_year_month(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::TemporalInvalidPlainYearMonth);
+
+    // 4. Let result be ? ParseISODateTime(item, « TemporalYearMonthString »).
+    auto parse_result = TRY(parse_iso_date_time(vm, item.as_string().utf8_string_view(), { { Production::TemporalYearMonthString } }));
+
+    // 5. Let calendar be result.[[Calendar]].
+    // 6. If calendar is empty, set calendar to "iso8601".
+    auto calendar = parse_result.calendar.value_or("iso8601"_string);
+
+    // 7. Set calendar to ? CanonicalizeCalendar(calendar).
+    calendar = TRY(canonicalize_calendar(vm, calendar));
+
+    // 8. Let isoDate be CreateISODateRecord(result.[[Year]], result.[[Month]], result.[[Day]]).
+    auto iso_date = create_iso_date_record(*parse_result.year, parse_result.month, parse_result.day);
+
+    // 9. Set result to ISODateToFields(calendar, isoDate, YEAR-MONTH).
+    auto result = iso_date_to_fields(calendar, iso_date, DateType::YearMonth);
+
+    // 10. Let resolvedOptions be ? GetOptionsObject(options).
+    auto resolved_options = TRY(get_options_object(vm, options));
+
+    // 11. Perform ? GetTemporalOverflowOption(resolvedOptions).
+    TRY(get_temporal_overflow_option(vm, resolved_options));
+
+    // 12. NOTE: The following operation is called with CONSTRAIN regardless of the value of overflow, in order for the
+    //     calendar to store a canonical value in the [[Day]] field of the [[ISODate]] internal slot of the result.
+    // 13. Set isoDate to ? CalendarYearMonthFromFields(calendar, result, CONSTRAIN).
+    iso_date = TRY(calendar_year_month_from_fields(vm, calendar, result, Overflow::Constrain));
+
+    // 14. Return ! CreateTemporalYearMonth(isoDate, calendar).
+    return MUST(create_temporal_year_month(vm, iso_date, move(calendar)));
+}
+
+// 9.5.3 ISOYearMonthWithinLimits ( isoDate ), https://tc39.es/proposal-temporal/#sec-temporal-isoyearmonthwithinlimits
+bool iso_year_month_within_limits(ISODate iso_date)
+{
+    // 1. If isoDate.[[Year]] < -271821 or isoDate.[[Year]] > 275760, then
+    if (iso_date.year < -271821 || iso_date.year > 275760) {
+        // a. Return false.
+        return false;
+    }
+
+    // 2. If isoDate.[[Year]] = -271821 and isoDate.[[Month]] < 4, then
+    if (iso_date.year == -271821 && iso_date.month < 4) {
+        // a. Return false.
+        return false;
+    }
+
+    // 3. If isoDate.[[Year]] = 275760 and isoDate.[[Month]] > 9, then
+    if (iso_date.year == 275760 && iso_date.month > 9) {
+        // a. Return false.
+        return false;
+    }
+
+    // 4. Return true.
+    return true;
+}
+
+// 9.5.5 CreateTemporalYearMonth ( isoDate, calendar [ , newTarget ] ), https://tc39.es/proposal-temporal/#sec-temporal-createtemporalyearmonth
+ThrowCompletionOr<GC::Ref<PlainYearMonth>> create_temporal_year_month(VM& vm, ISODate iso_date, String calendar, GC::Ptr<FunctionObject> new_target)
+{
+    auto& realm = *vm.current_realm();
+
+    // 1. If ISOYearMonthWithinLimits(isoDate) is false, throw a RangeError exception.
+    if (!iso_year_month_within_limits(iso_date))
+        return vm.throw_completion<RangeError>(ErrorType::TemporalInvalidPlainYearMonth);
+
+    // 2. If newTarget is not present, set newTarget to %Temporal.PlainYearMonth%.
+    if (!new_target)
+        new_target = realm.intrinsics().temporal_plain_year_month_constructor();
+
+    // 3. Let object be ? OrdinaryCreateFromConstructor(newTarget, "%Temporal.PlainYearMonth.prototype%", « [[InitializedTemporalYearMonth]], [[ISODate]], [[Calendar]] »).
+    // 4. Set object.[[ISODate]] to isoDate.
+    // 5. Set object.[[Calendar]] to calendar.
+    auto object = TRY(ordinary_create_from_constructor<PlainYearMonth>(vm, *new_target, &Intrinsics::temporal_plain_year_month_prototype, iso_date, move(calendar)));
+
+    // 6. Return object.
+    return object;
+}
+
+}