LibJS: Implement Temporal.Now

Author: https://github.com/trflynn89
Commit: f2c19f96f8
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2557
Reviewed-by: https://github.com/shannonbooth ✅

Libraries/LibJS/Runtime/Temporal/Now.cpp

@@ -0,0 +1,132 @@
+/*
+ * 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/Date.h>
+#include <LibJS/Runtime/Temporal/Instant.h>
+#include <LibJS/Runtime/Temporal/Now.h>
+#include <LibJS/Runtime/Temporal/PlainDate.h>
+#include <LibJS/Runtime/Temporal/PlainDateTime.h>
+#include <LibJS/Runtime/Temporal/PlainTime.h>
+#include <LibJS/Runtime/Temporal/TimeZone.h>
+
+namespace JS::Temporal {
+
+GC_DEFINE_ALLOCATOR(Now);
+
+// 2 The Temporal.Now Object, https://tc39.es/proposal-temporal/#sec-temporal-now-object
+Now::Now(Realm& realm)
+    : Object(ConstructWithPrototypeTag::Tag, realm.intrinsics().object_prototype())
+{
+}
+
+void Now::initialize(Realm& realm)
+{
+    Base::initialize(realm);
+
+    auto& vm = this->vm();
+
+    // 2.1.1 Temporal.Now [ %Symbol.toStringTag% ], https://tc39.es/proposal-temporal/#sec-temporal-now-%symbol.tostringtag%
+    define_direct_property(vm.well_known_symbol_to_string_tag(), PrimitiveString::create(vm, "Temporal.Now"_string), Attribute::Configurable);
+
+    u8 attr = Attribute::Writable | Attribute::Configurable;
+    define_native_function(realm, vm.names.timeZoneId, time_zone_id, 0, attr);
+    define_native_function(realm, vm.names.instant, instant, 0, attr);
+    define_native_function(realm, vm.names.plainDateTimeISO, plain_date_time_iso, 0, attr);
+    define_native_function(realm, vm.names.plainDateISO, plain_date_iso, 0, attr);
+    define_native_function(realm, vm.names.plainTimeISO, plain_time_iso, 0, attr);
+}
+
+// 2.2.1 Temporal.Now.timeZoneId ( ), https://tc39.es/proposal-temporal/#sec-temporal.now.timezoneid
+JS_DEFINE_NATIVE_FUNCTION(Now::time_zone_id)
+{
+    // 1. Return SystemTimeZoneIdentifier().
+    return PrimitiveString::create(vm, system_time_zone_identifier());
+}
+
+// 2.2.2 Temporal.Now.instant ( ), https://tc39.es/proposal-temporal/#sec-temporal.now.instant
+JS_DEFINE_NATIVE_FUNCTION(Now::instant)
+{
+    // 1. Let ns be SystemUTCEpochNanoseconds().
+    auto nanoseconds = system_utc_epoch_nanoseconds(vm);
+
+    // 2. Return ! CreateTemporalInstant(ns).
+    return MUST(create_temporal_instant(vm, BigInt::create(vm, move(nanoseconds))));
+}
+
+// 2.2.3 Temporal.Now.plainDateTimeISO ( [ temporalTimeZoneLike ] ), https://tc39.es/proposal-temporal/#sec-temporal.now.plaindatetimeiso
+JS_DEFINE_NATIVE_FUNCTION(Now::plain_date_time_iso)
+{
+    auto temporal_time_zone_like = vm.argument(0);
+
+    // 1. Let isoDateTime be ? SystemDateTime(temporalTimeZoneLike).
+    auto iso_date_time = TRY(system_date_time(vm, temporal_time_zone_like));
+
+    // 2. Return ! CreateTemporalDateTime(isoDateTime, "iso8601").
+    return MUST(create_temporal_date_time(vm, iso_date_time, "iso8601"_string));
+}
+
+// 2.2.5 Temporal.Now.plainDateISO ( [ temporalTimeZoneLike ] ), https://tc39.es/proposal-temporal/#sec-temporal.now.plaindateiso
+JS_DEFINE_NATIVE_FUNCTION(Now::plain_date_iso)
+{
+    auto temporal_time_zone_like = vm.argument(0);
+
+    // 1. Let isoDateTime be ? SystemDateTime(temporalTimeZoneLike).
+    auto iso_date_time = TRY(system_date_time(vm, temporal_time_zone_like));
+
+    // 2. Return ! CreateTemporalDate(isoDateTime.[[ISODate]], "iso8601").
+    return MUST(create_temporal_date(vm, iso_date_time.iso_date, "iso8601"_string));
+}
+
+// 2.2.6 Temporal.Now.plainTimeISO ( [ temporalTimeZoneLike ] ), https://tc39.es/proposal-temporal/#sec-temporal.now.plaintimeiso
+JS_DEFINE_NATIVE_FUNCTION(Now::plain_time_iso)
+{
+    auto temporal_time_zone_like = vm.argument(0);
+
+    // 1. Let isoDateTime be ? SystemDateTime(temporalTimeZoneLike).
+    auto iso_date_time = TRY(system_date_time(vm, temporal_time_zone_like));
+
+    // 2. Return ! CreateTemporalTime(isoDateTime.[[Time]]).
+    return MUST(create_temporal_time(vm, iso_date_time.time));
+}
+
+// 2.3.3 SystemUTCEpochNanoseconds ( ), https://tc39.es/proposal-temporal/#sec-temporal-systemutcepochnanoseconds
+Crypto::SignedBigInteger system_utc_epoch_nanoseconds(VM& vm)
+{
+    // 1. Let global be GetGlobalObject().
+    auto const& global = vm.get_global_object();
+
+    // 2. Let nowNs be HostSystemUTCEpochNanoseconds(global).
+    auto now_ns = vm.host_system_utc_epoch_nanoseconds(global);
+
+    // 3. Return ℤ(nowNs).
+    return now_ns;
+}
+
+// 2.3.4 SystemDateTime ( temporalTimeZoneLike ), https://tc39.es/proposal-temporal/#sec-temporal-systemdatetime
+ThrowCompletionOr<ISODateTime> system_date_time(VM& vm, Value temporal_time_zone_like)
+{
+    String time_zone;
+
+    // 1. If temporalTimeZoneLike is undefined, then
+    if (temporal_time_zone_like.is_undefined()) {
+        // a. Let timeZone be SystemTimeZoneIdentifier().
+        time_zone = system_time_zone_identifier();
+    }
+    // 2. Else,
+    else {
+        // a. Let timeZone be ? ToTemporalTimeZoneIdentifier(temporalTimeZoneLike).
+        time_zone = TRY(to_temporal_time_zone_identifier(vm, temporal_time_zone_like));
+    }
+
+    // 3. Let epochNs be SystemUTCEpochNanoseconds().
+    auto epoch_nanoseconds = system_utc_epoch_nanoseconds(vm);
+
+    // 4. Return GetISODateTimeFor(timeZone, epochNs).
+    return get_iso_date_time_for(time_zone, epoch_nanoseconds);
+}
+
+}