From 300a22f9b9f289f4e4a0733facbe1cad4c8712f4 Mon Sep 17 00:00:00 2001
From: Linus Groh <mail@linusgroh.de>
Date: Thu, 15 Jul 2021 23:34:53 +0100
Subject: [PATCH] LibJS: Implement Temporal.Duration.prototype.years

---
 .../LibJS/Runtime/CommonPropertyNames.h       |  3 +-
 .../Runtime/Temporal/DurationPrototype.cpp    | 29 +++++++++++++++++++
 .../Runtime/Temporal/DurationPrototype.h      |  3 ++
 .../Duration/Duration.prototype.years.js      | 14 +++++++++
 4 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 Userland/Libraries/LibJS/Tests/builtins/Temporal/Duration/Duration.prototype.years.js

diff --git a/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h b/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h
index b555d8501c798c..80e03f834707a2 100644
--- a/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h
+++ b/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h
@@ -352,7 +352,8 @@ namespace JS {
     P(valueOf)                               \
     P(values)                                \
     P(warn)                                  \
-    P(writable)
+    P(writable)                              \
+    P(years)
 
 struct CommonPropertyNames {
     PropertyName and_ { "and", PropertyName::StringMayBeNumber::No };
diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.cpp b/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.cpp
index 7310ed3a14c581..7f6d72da86b9e2 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.cpp
@@ -5,6 +5,7 @@
  */
 
 #include <LibJS/Runtime/GlobalObject.h>
+#include <LibJS/Runtime/Temporal/Duration.h>
 #include <LibJS/Runtime/Temporal/DurationPrototype.h>
 
 namespace JS::Temporal {
@@ -23,6 +24,34 @@ void DurationPrototype::initialize(GlobalObject& global_object)
 
     // 7.3.2 Temporal.Duration.prototype[ @@toStringTag ], https://tc39.es/proposal-temporal/#sec-temporal.duration.prototype-@@tostringtag
     define_direct_property(*vm.well_known_symbol_to_string_tag(), js_string(vm.heap(), "Temporal.Duration"), Attribute::Configurable);
+
+    define_native_accessor(vm.names.years, years_getter, {}, Attribute::Configurable);
+}
+
+static Duration* typed_this(GlobalObject& global_object)
+{
+    auto& vm = global_object.vm();
+    auto* this_object = vm.this_value(global_object).to_object(global_object);
+    if (!this_object)
+        return {};
+    if (!is<Duration>(this_object)) {
+        vm.throw_exception<TypeError>(global_object, ErrorType::NotA, "Temporal.Duration");
+        return {};
+    }
+    return static_cast<Duration*>(this_object);
+}
+
+// 7.3.3 get Temporal.Duration.prototype.years, https://tc39.es/proposal-temporal/#sec-get-temporal.duration.prototype.years
+JS_DEFINE_NATIVE_FUNCTION(DurationPrototype::years_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.[[Years]].
+    return Value(duration->years());
 }
 
 }
diff --git a/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.h b/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.h
index b758b546aa149c..ee5b1f7ab89179 100644
--- a/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.h
+++ b/Userland/Libraries/LibJS/Runtime/Temporal/DurationPrototype.h
@@ -17,6 +17,9 @@ class DurationPrototype final : public Object {
     explicit DurationPrototype(GlobalObject&);
     virtual void initialize(GlobalObject&) override;
     virtual ~DurationPrototype() override = default;
+
+private:
+    JS_DECLARE_NATIVE_FUNCTION(years_getter);
 };
 
 }
diff --git a/Userland/Libraries/LibJS/Tests/builtins/Temporal/Duration/Duration.prototype.years.js b/Userland/Libraries/LibJS/Tests/builtins/Temporal/Duration/Duration.prototype.years.js
new file mode 100644
index 00000000000000..3b59d4c9ee7057
--- /dev/null
+++ b/Userland/Libraries/LibJS/Tests/builtins/Temporal/Duration/Duration.prototype.years.js
@@ -0,0 +1,14 @@
+describe("correct behavior", () => {
+    test("basic functionality", () => {
+        const duration = new Temporal.Duration(123);
+        expect(duration.years).toBe(123);
+    });
+});
+
+test("errors", () => {
+    test("this value must be a Temporal.Duration object", () => {
+        expect(() => {
+            Reflect.get(Temporal.Duration.prototype, "years", "foo");
+        }).toThrowWithMessage(TypeError, "Not a Temporal.Duration");
+    });
+});