LibJS: Implement Temporal.PlainMonthDay.prototype.toString()

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

@@ -6,6 +6,7 @@
 
 #include <LibJS/Runtime/AbstractOperations.h>
 #include <LibJS/Runtime/GlobalObject.h>
+#include <LibJS/Runtime/Temporal/Calendar.h>
 #include <LibJS/Runtime/Temporal/PlainDate.h>
 #include <LibJS/Runtime/Temporal/PlainMonthDay.h>
 #include <LibJS/Runtime/Temporal/PlainMonthDayConstructor.h>
@@ -59,4 +60,37 @@ PlainMonthDay* create_temporal_month_day(GlobalObject& global_object, u8 iso_mon
     return object;
 }
 
+// 10.5.3 TemporalMonthDayToString ( monthDay, showCalendar ), https://tc39.es/proposal-temporal/#sec-temporal-temporalmonthdaytostring
+Optional<String> temporal_month_day_to_string(GlobalObject& global_object, PlainMonthDay& month_day, StringView show_calendar)
+{
+    auto& vm = global_object.vm();
+
+    // 1. Assert: Type(monthDay) is Object.
+    // 2. Assert: monthDay has an [[InitializedTemporalMonthDay]] internal slot.
+
+    // 3. Let month be monthDay.[[ISOMonth]] formatted as a two-digit decimal number, padded to the left with a zero if necessary.
+    // 4. Let day be monthDay.[[ISODay]] formatted as a two-digit decimal number, padded to the left with a zero if necessary.
+    // 5. Let result be the string-concatenation of month, the code unit 0x002D (HYPHEN-MINUS), and day.
+    auto result = String::formatted("{:02}-{:02}", month_day.iso_month(), month_day.iso_day());
+
+    // 6. Let calendarID be ? ToString(monthDay.[[Calendar]]).
+    auto calendar_id = Value(&month_day.calendar()).to_string(global_object);
+    if (vm.exception())
+        return {};
+
+    // 7. If calendarID is not "iso8601", then
+    if (calendar_id != "iso8601"sv) {
+        // a. Let year be ! PadISOYear(monthDay.[[ISOYear]]).
+        // b. Set result to the string-concatenation of year, the code unit 0x002D (HYPHEN-MINUS), and result.
+        result = String::formatted("{}-{}", pad_iso_year(month_day.iso_year()), result);
+    }
+
+    // 8. Let calendarString be ! FormatCalendarAnnotation(calendarID, showCalendar).
+    auto calendar_string = format_calendar_annotation(calendar_id, show_calendar);
+
+    // 9. Set result to the string-concatenation of result and calendarString.
+    // 10. Return result.
+    return String::formatted("{}{}", result, calendar_string);
+}
+
 }

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

@@ -40,5 +40,6 @@ struct ISOMonthDay {
 };
 
 PlainMonthDay* create_temporal_month_day(GlobalObject&, u8 iso_month, u8 iso_day, Object& calendar, i32 reference_iso_year, FunctionObject* new_target = nullptr);
+Optional<String> temporal_month_day_to_string(GlobalObject&, PlainMonthDay&, StringView show_calendar);
 
 }

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

@@ -6,6 +6,7 @@
 
 #include <AK/TypeCasts.h>
 #include <LibJS/Runtime/GlobalObject.h>
+#include <LibJS/Runtime/Temporal/AbstractOperations.h>
 #include <LibJS/Runtime/Temporal/Calendar.h>
 #include <LibJS/Runtime/Temporal/PlainMonthDay.h>
 #include <LibJS/Runtime/Temporal/PlainMonthDayPrototype.h>
@@ -32,6 +33,7 @@ void PlainMonthDayPrototype::initialize(GlobalObject& global_object)
     define_native_accessor(vm.names.day, day_getter, {}, Attribute::Configurable);
 
     u8 attr = Attribute::Writable | Attribute::Configurable;
+    define_native_function(vm.names.toString, to_string, 0, attr);
     define_native_function(vm.names.valueOf, value_of, 0, attr);
     define_native_function(vm.names.getISOFields, get_iso_fields, 0, attr);
 }
@@ -94,6 +96,33 @@ JS_DEFINE_NATIVE_FUNCTION(PlainMonthDayPrototype::day_getter)
     return Value(calendar_day(global_object, calendar, *month_day));
 }
 
+// 10.3.8 Temporal.PlainMonthDay.prototype.toString ( [ options ] ), https://tc39.es/proposal-temporal/#sec-temporal.plainmonthday.prototype.tostring
+JS_DEFINE_NATIVE_FUNCTION(PlainMonthDayPrototype::to_string)
+{
+    // 1. Let monthDay be the this value.
+    // 2. Perform ? RequireInternalSlot(monthDay, [[InitializedTemporalMonthDay]]).
+    auto* month_day = typed_this(global_object);
+    if (vm.exception())
+        return {};
+
+    // 3. Set options to ? GetOptionsObject(options).
+    auto* options = get_options_object(global_object, vm.argument(0));
+    if (vm.exception())
+        return {};
+
+    // 4. Let showCalendar be ? ToShowCalendarOption(options).
+    auto show_calendar = to_show_calendar_option(global_object, *options);
+    if (vm.exception())
+        return {};
+
+    // 5. Return ? TemporalMonthDayToString(monthDay, showCalendar).
+    auto string = temporal_month_day_to_string(global_object, *month_day, *show_calendar);
+    if (vm.exception())
+        return {};
+
+    return js_string(vm, *string);
+}
+
 // 10.3.11 Temporal.PlainMonthDay.prototype.valueOf ( ), https://tc39.es/proposal-temporal/#sec-temporal.plainmonthday.prototype.valueof
 JS_DEFINE_NATIVE_FUNCTION(PlainMonthDayPrototype::value_of)
 {

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

@@ -22,6 +22,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(calendar_getter);
     JS_DECLARE_NATIVE_FUNCTION(month_code_getter);
     JS_DECLARE_NATIVE_FUNCTION(day_getter);
+    JS_DECLARE_NATIVE_FUNCTION(to_string);
     JS_DECLARE_NATIVE_FUNCTION(value_of);
     JS_DECLARE_NATIVE_FUNCTION(get_iso_fields);
 };

Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainMonthDay/PlainMonthDay.prototype.toString.js

@@ -0,0 +1,36 @@
+describe("correct behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.PlainMonthDay.prototype.toString).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        let plainMonthDay;
+
+        plainMonthDay = new Temporal.PlainMonthDay(7, 6);
+        expect(plainMonthDay.toString()).toBe("07-06");
+        expect(plainMonthDay.toString({ calendarName: "auto" })).toBe("07-06");
+        expect(plainMonthDay.toString({ calendarName: "always" })).toBe("07-06[u-ca=iso8601]");
+        expect(plainMonthDay.toString({ calendarName: "never" })).toBe("07-06");
+
+        plainMonthDay = new Temporal.PlainMonthDay(7, 6, { toString: () => "foo" }, 2021);
+        expect(plainMonthDay.toString()).toBe("2021-07-06[u-ca=foo]");
+        expect(plainMonthDay.toString({ calendarName: "auto" })).toBe("2021-07-06[u-ca=foo]");
+        expect(plainMonthDay.toString({ calendarName: "always" })).toBe("2021-07-06[u-ca=foo]");
+        expect(plainMonthDay.toString({ calendarName: "never" })).toBe("2021-07-06");
+    });
+});
+
+describe("errors", () => {
+    test("this value must be a Temporal.PlainMonthDay object", () => {
+        expect(() => {
+            Temporal.PlainMonthDay.prototype.toString.call("foo");
+        }).toThrowWithMessage(TypeError, "Not a Temporal.PlainMonthDay");
+    });
+
+    test("calendarName option must be one of 'auto', 'always', 'never'", () => {
+        const plainMonthDay = new Temporal.PlainMonthDay(7, 6);
+        expect(() => {
+            plainMonthDay.toString({ calendarName: "foo" });
+        }).toThrowWithMessage(RangeError, "foo is not a valid value for option calendarName");
+    });
+});