LibJS: Implement Temporal.Duration.prototype.seconds

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -271,6 +271,7 @@ namespace JS {
     P(revoke)                                \
     P(round)                                 \
     P(seal)                                  \
+    P(seconds)                               \
     P(set)                                   \
     P(setBigInt64)                           \
     P(setBigUint64)                          \

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

@@ -31,6 +31,7 @@ void DurationPrototype::initialize(GlobalObject& global_object)
     define_native_accessor(vm.names.days, days_getter, {}, Attribute::Configurable);
     define_native_accessor(vm.names.hours, hours_getter, {}, Attribute::Configurable);
     define_native_accessor(vm.names.minutes, minutes_getter, {}, Attribute::Configurable);
+    define_native_accessor(vm.names.seconds, seconds_getter, {}, Attribute::Configurable);
 }
 
 static Duration* typed_this(GlobalObject& global_object)
@@ -124,4 +125,17 @@ JS_DEFINE_NATIVE_FUNCTION(DurationPrototype::minutes_getter)
     return Value(duration->minutes());
 }
 
+// 7.3.9 get Temporal.Duration.prototype.seconds, https://tc39.es/proposal-temporal/#sec-get-temporal.duration.prototype.seconds
+JS_DEFINE_NATIVE_FUNCTION(DurationPrototype::seconds_getter)
+{
+    // 1. Let duration be the this value.
+    // 2. Perform ? RequireInternalSlot(duration, [[InitializedTemporalDuration]]).
+    auto* duration = typed_this(global_object);
+    if (vm.exception())
+        return {};
+
+    // 3. Return duration.[[Seconds]].
+    return Value(duration->seconds());
+}
+
 }

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

@@ -25,6 +25,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(days_getter);
     JS_DECLARE_NATIVE_FUNCTION(hours_getter);
     JS_DECLARE_NATIVE_FUNCTION(minutes_getter);
+    JS_DECLARE_NATIVE_FUNCTION(seconds_getter);
 };
 
 }

Userland/Libraries/LibJS/Tests/builtins/Temporal/Duration/Duration.prototype.seconds.js

@@ -0,0 +1,14 @@
+describe("correct behavior", () => {
+    test("basic functionality", () => {
+        const duration = new Temporal.Duration(0, 0, 0, 0, 0, 0, 123);
+        expect(duration.seconds).toBe(123);
+    });
+});
+
+test("errors", () => {
+    test("this value must be a Temporal.Duration object", () => {
+        expect(() => {
+            Reflect.get(Temporal.Duration.prototype, "seconds", "foo");
+        }).toThrowWithMessage(TypeError, "Not a Temporal.Duration");
+    });
+});