From b8db0ddc708a097557e88ae9b07d6efdea250e2b Mon Sep 17 00:00:00 2001
From: Luke Wilde <lukew@serenityos.org>
Date: Fri, 5 Nov 2021 01:35:37 +0000
Subject: [PATCH] LibJS: Implement
 Temporal.ZonedDateTime.prototype.withCalendar

---
 .../Temporal/ZonedDateTimePrototype.cpp       | 15 +++++++
 .../Runtime/Temporal/ZonedDateTimePrototype.h |  1 +
 .../ZonedDateTime.prototype.withCalendar.js   | 43 +++++++++++++++++++
 3 files changed, 59 insertions(+)
 create mode 100644 Userland/Libraries/LibJS/Tests/builtins/Temporal/ZonedDateTime/ZonedDateTime.prototype.withCalendar.js

diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.cpp
index ad47ded159..0224503483 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.cpp
@@ -67,6 +67,7 @@ void ZonedDateTimePrototype::initialize(GlobalObject& global_object)
     define_native_function(vm.names.withPlainTime, with_plain_time, 0, attr);
     define_native_function(vm.names.withPlainDate, with_plain_date, 1, attr);
     define_native_function(vm.names.withTimeZone, with_time_zone, 1, attr);
+    define_native_function(vm.names.withCalendar, with_calendar, 1, attr);
     define_native_function(vm.names.valueOf, value_of, 0, attr);
     define_native_function(vm.names.startOfDay, start_of_day, 0, attr);
     define_native_function(vm.names.toInstant, to_instant, 0, attr);
@@ -793,6 +794,20 @@ JS_DEFINE_NATIVE_FUNCTION(ZonedDateTimePrototype::with_time_zone)
     return MUST(create_temporal_zoned_date_time(global_object, zoned_date_time->nanoseconds(), *time_zone, zoned_date_time->calendar()));
 }
 
+// 6.3.34 Temporal.ZonedDateTime.prototype.withCalendar ( calendarLike ), https://tc39.es/proposal-temporal/#sec-temporal.zoneddatetime.prototype.withcalendar
+JS_DEFINE_NATIVE_FUNCTION(ZonedDateTimePrototype::with_calendar)
+{
+    // 1. Let zonedDateTime be the this value.
+    // 2. Perform ? RequireInternalSlot(zonedDateTime, [[InitializedTemporalZonedDateTime]]).
+    auto* zoned_date_time = TRY(typed_this_object(global_object));
+
+    // 3. Let calendar be ? ToTemporalCalendar(calendarLike).
+    auto* calendar = TRY(to_temporal_calendar(global_object, vm.argument(0)));
+
+    // 4. Return ! CreateTemporalZonedDateTime(zonedDateTime.[[Nanoseconds]], zonedDateTime.[[TimeZone]], calendar).
+    return MUST(create_temporal_zoned_date_time(global_object, zoned_date_time->nanoseconds(), zoned_date_time->time_zone(), *calendar));
+}
+
 // 6.3.44 Temporal.ZonedDateTime.prototype.valueOf ( ), https://tc39.es/proposal-temporal/#sec-temporal.zoneddatetime.prototype.valueof
 JS_DEFINE_NATIVE_FUNCTION(ZonedDateTimePrototype::value_of)
 {
diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.h b/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.h
index 416b2bb20a..208a494f77 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.h
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/ZonedDateTimePrototype.h
@@ -52,6 +52,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(with_plain_time);
     JS_DECLARE_NATIVE_FUNCTION(with_plain_date);
     JS_DECLARE_NATIVE_FUNCTION(with_time_zone);
+    JS_DECLARE_NATIVE_FUNCTION(with_calendar);
     JS_DECLARE_NATIVE_FUNCTION(value_of);
     JS_DECLARE_NATIVE_FUNCTION(start_of_day);
     JS_DECLARE_NATIVE_FUNCTION(to_instant);
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Temporal/ZonedDateTime/ZonedDateTime.prototype.withCalendar.js b/Userland/Libraries/LibJS/Tests/builtins/Temporal/ZonedDateTime/ZonedDateTime.prototype.withCalendar.js
new file mode 100644
index 0000000000..3361e0e15c
--- /dev/null
+++ b/Userland/Libraries/LibJS/Tests/builtins/Temporal/ZonedDateTime/ZonedDateTime.prototype.withCalendar.js
@@ -0,0 +1,43 @@
+describe("correct behavior", () => {
+    test("length is 1", () => {
+        expect(Temporal.ZonedDateTime.prototype.withCalendar).toHaveLength(1);
+    });
+
+    test("basic functionality", () => {
+        const object = {};
+        const zonedDateTime = new Temporal.ZonedDateTime(1n, {}, object);
+        expect(zonedDateTime.calendar).toBe(object);
+
+        const calendar = new Temporal.Calendar("iso8601");
+        const withCalendarZonedDateTime = zonedDateTime.withCalendar(calendar);
+        expect(withCalendarZonedDateTime.calendar).toBe(calendar);
+    });
+
+    test("from calendar string", () => {
+        const object = {};
+        const zonedDateTime = new Temporal.ZonedDateTime(1n, {}, object);
+        expect(zonedDateTime.calendar).toBe(object);
+
+        const withCalendarZonedDateTime = zonedDateTime.withCalendar("iso8601");
+        expect(withCalendarZonedDateTime.calendar).toBeInstanceOf(Temporal.Calendar);
+        expect(withCalendarZonedDateTime.calendar.id).toBe("iso8601");
+    });
+});
+
+describe("errors", () => {
+    test("this value must be a Temporal.ZonedDateTime object", () => {
+        expect(() => {
+            Temporal.ZonedDateTime.prototype.withCalendar.call("foo");
+        }).toThrowWithMessage(TypeError, "Not an object of type Temporal.ZonedDateTime");
+    });
+
+    // FIXME: Enable this when calendar string parsing is implemented.
+    test.skip("from invalid calendar string", () => {
+        const zonedDateTime = new Temporal.ZonedDateTime(1n, {}, {});
+
+        // FIXME: Use "toThrowWithMessage" once this has an error message.
+        expect(() => {
+            zonedDateTime.withCalendar("iso8602foobar");
+        }).toThrow(RangeError);
+    });
+});