LibJS: Implement Temporal.TimeZone.prototype.id

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -183,6 +183,7 @@ namespace JS {
     P(hasOwn)                                \
     P(hasOwnProperty)                        \
     P(hypot)                                 \
+    P(id)                                    \
     P(ignoreCase)                            \
     P(imul)                                  \
     P(includes)                              \

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

@@ -23,6 +23,7 @@ void TimeZonePrototype::initialize(GlobalObject& global_object)
     auto& vm = this->vm();
 
     u8 attr = Attribute::Writable | Attribute::Configurable;
+    define_native_accessor(vm.names.id, id_getter, {}, Attribute::Configurable);
     define_native_function(vm.names.toString, to_string, 0, attr);
     define_native_function(vm.names.toJSON, to_json, 0, attr);
 
@@ -43,6 +44,16 @@ static TimeZone* typed_this(GlobalObject& global_object)
     return static_cast<TimeZone*>(this_object);
 }
 
+// 11.4.3 get Temporal.TimeZone.prototype.id, https://tc39.es/proposal-temporal/#sec-get-temporal.timezone.prototype.id
+JS_DEFINE_NATIVE_FUNCTION(TimeZonePrototype::id_getter)
+{
+    // 1. Let timeZone be the this value.
+    auto time_zone = vm.this_value(global_object);
+
+    // 2. Return ? ToString(timeZone).
+    return js_string(vm, time_zone.to_string(global_object));
+}
+
 // 11.4.11 Temporal.TimeZone.prototype.toString ( ), https://tc39.es/proposal-temporal/#sec-temporal.timezone.prototype.tostring
 JS_DEFINE_NATIVE_FUNCTION(TimeZonePrototype::to_string)
 {

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

@@ -19,6 +19,7 @@ public:
     virtual ~TimeZonePrototype() override = default;
 
 private:
+    JS_DECLARE_NATIVE_FUNCTION(id_getter);
     JS_DECLARE_NATIVE_FUNCTION(to_string);
     JS_DECLARE_NATIVE_FUNCTION(to_json);
 };

Userland/Libraries/LibJS/Tests/builtins/Temporal/TimeZone/TimeZone.prototype.id.js

@@ -0,0 +1,10 @@
+describe("correct behavior", () => {
+    test("basic functionality", () => {
+        const timeZone = new Temporal.TimeZone("UTC");
+        expect(timeZone.id).toBe("UTC");
+    });
+
+    test("works with any this value", () => {
+        expect(Reflect.get(Temporal.TimeZone.prototype, "id", "foo")).toBe("foo");
+    });
+});