LibJS: Implement Temporal.Instant.prototype.toZonedDateTime()

Author: https://github.com/linusg
Commit: https://github.com/SerenityOS/serenity/commit/6607d1dfb1f
Pull-request: https://github.com/SerenityOS/serenity/pull/9904
Reviewed-by: https://github.com/IdanHo ✅

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -435,6 +435,7 @@ namespace JS {
     P(toTimeString)                          \
     P(toUpperCase)                           \
     P(toUTCString)                           \
+    P(toZonedDateTime)                       \
     P(trace)                                 \
     P(trim)                                  \
     P(trimEnd)                               \

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

@@ -22,6 +22,7 @@ public:
     virtual ~Instant() override = default;
 
     [[nodiscard]] BigInt const& nanoseconds() const { return m_nanoseconds; }
+    [[nodiscard]] BigInt& nanoseconds() { return m_nanoseconds; }
 
 private:
     virtual void visit_edges(Visitor&) override;

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

@@ -8,10 +8,12 @@
 #include <LibCrypto/BigInt/UnsignedBigInteger.h>
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/Temporal/AbstractOperations.h>
+#include <LibJS/Runtime/Temporal/Calendar.h>
 #include <LibJS/Runtime/Temporal/Duration.h>
 #include <LibJS/Runtime/Temporal/Instant.h>
 #include <LibJS/Runtime/Temporal/InstantPrototype.h>
 #include <LibJS/Runtime/Temporal/TimeZone.h>
+#include <LibJS/Runtime/Temporal/ZonedDateTime.h>
 
 namespace JS::Temporal {
 
@@ -46,6 +48,7 @@ void InstantPrototype::initialize(GlobalObject& global_object)
     define_native_function(vm.names.toLocaleString, to_locale_string, 0, attr);
     define_native_function(vm.names.toJSON, to_json, 0, attr);
     define_native_function(vm.names.valueOf, value_of, 0, attr);
+    define_native_function(vm.names.toZonedDateTime, to_zoned_date_time, 1, attr);
 }
 
 static Instant* typed_this(GlobalObject& global_object)
@@ -509,4 +512,60 @@ JS_DEFINE_NATIVE_FUNCTION(InstantPrototype::value_of)
     return {};
 }
 
+// 8.3.17 Temporal.Instant.prototype.toZonedDateTime ( item ), https://tc39.es/proposal-temporal/#sec-temporal.instant.prototype.tozoneddatetime
+JS_DEFINE_NATIVE_FUNCTION(InstantPrototype::to_zoned_date_time)
+{
+    auto item = vm.argument(0);
+
+    // 1. Let instant be the this value.
+    // 2. Perform ? RequireInternalSlot(instant, [[InitializedTemporalInstant]]).
+    auto* instant = typed_this(global_object);
+    if (vm.exception())
+        return {};
+
+    // 3. If Type(item) is not Object, then
+    if (!item.is_object()) {
+        // a. Throw a TypeError exception.
+        vm.throw_exception<TypeError>(global_object, ErrorType::NotAnObject, item);
+        return {};
+    }
+
+    // 4. Let calendarLike be ? Get(item, "calendar").
+    auto calendar_like = item.as_object().get(vm.names.calendar);
+    if (vm.exception())
+        return {};
+
+    // 5. If calendarLike is undefined, then
+    if (calendar_like.is_undefined()) {
+        // a. Throw a TypeError exception.
+        vm.throw_exception<TypeError>(global_object, ErrorType::TemporalMissingRequiredProperty, vm.names.calendar.as_string());
+        return {};
+    }
+
+    // 6. Let calendar be ? ToTemporalCalendar(calendarLike).
+    auto* calendar = to_temporal_calendar(global_object, calendar_like);
+    if (vm.exception())
+        return {};
+
+    // 7. Let temporalTimeZoneLike be ? Get(item, "timeZone").
+    auto temporal_time_zone_like = item.as_object().get(vm.names.timeZone);
+    if (vm.exception())
+        return {};
+
+    // 8. If temporalTimeZoneLike is undefined, then
+    if (temporal_time_zone_like.is_undefined()) {
+        // a. Throw a TypeError exception.
+        vm.throw_exception<TypeError>(global_object, ErrorType::TemporalMissingRequiredProperty, vm.names.timeZone.as_string());
+        return {};
+    }
+
+    // 9. Let timeZone be ? ToTemporalTimeZone(temporalTimeZoneLike).
+    auto* time_zone = to_temporal_time_zone(global_object, temporal_time_zone_like);
+    if (vm.exception())
+        return {};
+
+    // 10. Return ? CreateTemporalZonedDateTime(instant.[[Nanoseconds]], timeZone, calendar).
+    return create_temporal_zoned_date_time(global_object, instant->nanoseconds(), *time_zone, *calendar);
+}
+
 }

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

@@ -33,6 +33,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(to_locale_string);
     JS_DECLARE_NATIVE_FUNCTION(to_json);
     JS_DECLARE_NATIVE_FUNCTION(value_of);
+    JS_DECLARE_NATIVE_FUNCTION(to_zoned_date_time);
 };
 
 }

Userland/Libraries/LibJS/Tests/builtins/Temporal/Instant/Instant.prototype.toZonedDateTime.js

@@ -0,0 +1,54 @@
+describe("correct behavior", () => {
+    test("length is 1", () => {
+        expect(Temporal.Instant.prototype.toZonedDateTime).toHaveLength(1);
+    });
+
+    test("basic functionality", () => {
+        const instant = new Temporal.Instant(1625614921123456789n);
+        const calendar = new Temporal.Calendar("iso8601");
+        const timeZone = new Temporal.TimeZone("UTC");
+        const zonedDateTime = instant.toZonedDateTime({ calendar, timeZone });
+        expect(zonedDateTime.year).toBe(2021);
+        expect(zonedDateTime.month).toBe(7);
+        expect(zonedDateTime.day).toBe(6);
+        expect(zonedDateTime.hour).toBe(23);
+        expect(zonedDateTime.minute).toBe(42);
+        expect(zonedDateTime.second).toBe(1);
+        expect(zonedDateTime.millisecond).toBe(123);
+        expect(zonedDateTime.microsecond).toBe(456);
+        expect(zonedDateTime.nanosecond).toBe(789);
+        expect(zonedDateTime.calendar).toBe(calendar);
+        expect(zonedDateTime.timeZone).toBe(timeZone);
+    });
+});
+
+describe("errors", () => {
+    test("this value must be a Temporal.Instant object", () => {
+        expect(() => {
+            Temporal.Instant.prototype.toZonedDateTime.call("foo");
+        }).toThrowWithMessage(TypeError, "Not a Temporal.Instant");
+    });
+
+    test("items argument must be an object", () => {
+        const instant = new Temporal.Instant(0n);
+        for (const value of [123, NaN, Infinity, true, false, null, undefined]) {
+            expect(() => {
+                instant.toZonedDateTime(value);
+            }).toThrowWithMessage(TypeError, `${value} is not an object`);
+        }
+    });
+
+    test("items argument must have a 'calendar' property", () => {
+        const instant = new Temporal.Instant(0n);
+        expect(() => {
+            instant.toZonedDateTime({});
+        }).toThrowWithMessage(TypeError, "Required property calendar is missing or undefined");
+    });
+
+    test("items argument must have a 'timeZone' property", () => {
+        const instant = new Temporal.Instant(0n);
+        expect(() => {
+            instant.toZonedDateTime({ calendar: {} });
+        }).toThrowWithMessage(TypeError, "Required property timeZone is missing or undefined");
+    });
+});