LibJS: Implement Temporal.PlainYearMonth.prototype.toLocaleString()

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

@@ -428,6 +428,7 @@ JS_DEFINE_NATIVE_FUNCTION(PlainDatePrototype::to_string)
 }
 
 // 3.3.29 Temporal.PlainDate.prototype.toLocaleString ( [ locales [ , options ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.plaindate.prototype.tolocalestring
+// NOTE: This is the minimum toLocaleString implementation for engines without ECMA-402.
 JS_DEFINE_NATIVE_FUNCTION(PlainDatePrototype::to_locale_string)
 {
  // 1. Let temporalDate be the this value.

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

@@ -39,6 +39,7 @@ void PlainYearMonthPrototype::initialize(GlobalObject& global_object)
 
  u8 attr = Attribute::Writable | Attribute::Configurable;
  define_native_function(vm.names.toString, to_string, 0, attr);
+ define_native_function(vm.names.toLocaleString, to_locale_string, 0, attr);
  define_native_function(vm.names.valueOf, value_of, 0, attr);
  define_native_function(vm.names.getISOFields, get_iso_fields, 0, attr);
 }
@@ -208,6 +209,24 @@ JS_DEFINE_NATIVE_FUNCTION(PlainYearMonthPrototype::to_string)
  return js_string(vm, *string);
 }
 
+// 9.3.18 Temporal.PlainYearMonth.prototype.toLocaleString ( [ locales [ , options ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.plainyearmonth.prototype.tolocalestring
+// NOTE: This is the minimum toLocaleString implementation for engines without ECMA-402.
+JS_DEFINE_NATIVE_FUNCTION(PlainYearMonthPrototype::to_locale_string)
+{
+ // 1. Let yearMonth be the this value.
+ // 2. Perform ? RequireInternalSlot(yearMonth, [[InitializedTemporalYearMonth]]).
+ auto* year_month = typed_this(global_object);
+ if (vm.exception())
+ return {};
+
+ // 3. Return ? TemporalYearMonthToString(yearMonth, "auto").
+ auto string = temporal_year_month_to_string(global_object, *year_month, "auto"sv);
+ if (vm.exception())
+ return {};
+
+ return js_string(vm, *string);
+}
+
 // 9.3.20 Temporal.PlainYearMonth.prototype.valueOf ( ), https://tc39.es/proposal-temporal/#sec-temporal.plainyearmonth.prototype.valueof
 JS_DEFINE_NATIVE_FUNCTION(PlainYearMonthPrototype::value_of)
 {

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

@@ -28,6 +28,7 @@ class PlainYearMonthPrototype final : public Object {
  JS_DECLARE_NATIVE_FUNCTION(months_in_year_getter);
  JS_DECLARE_NATIVE_FUNCTION(in_leap_year_getter);
  JS_DECLARE_NATIVE_FUNCTION(to_string);
+ JS_DECLARE_NATIVE_FUNCTION(to_locale_string);
  JS_DECLARE_NATIVE_FUNCTION(value_of);
  JS_DECLARE_NATIVE_FUNCTION(get_iso_fields);
 };

Userland/Libraries/LibJS/Tests/builtins/Temporal/PlainYearMonth/PlainYearMonth.prototype.toLocaleString.js

@@ -0,0 +1,23 @@
+describe("correct behavior", () => {
+ test("length is 0", () => {
+ expect(Temporal.PlainYearMonth.prototype.toLocaleString).toHaveLength(0);
+ });
+
+ test("basic functionality", () => {
+ let plainYearMonth;
+
+ plainYearMonth = new Temporal.PlainYearMonth(2021, 7);
+ expect(plainYearMonth.toLocaleString()).toBe("2021-07");
+
+ plainYearMonth = new Temporal.PlainYearMonth(2021, 7, { toString: () => "foo" }, 6);
+ expect(plainYearMonth.toLocaleString()).toBe("2021-07-06[u-ca=foo]");
+ });
+});
+
+describe("errors", () => {
+ test("this value must be a Temporal.PlainYearMonth object", () => {
+ expect(() => {
+ Temporal.PlainYearMonth.prototype.toLocaleString.call("foo");
+ }).toThrowWithMessage(TypeError, "Not a Temporal.PlainYearMonth");
+ });
+});