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

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

@@ -47,6 +47,7 @@ void DurationPrototype::initialize(GlobalObject& global_object)
     define_native_function(vm.names.abs, abs, 0, attr);
     define_native_function(vm.names.toString, to_string, 0, attr);
     define_native_function(vm.names.toJSON, to_json, 0, attr);
+    define_native_function(vm.names.toLocaleString, to_locale_string, 0, attr);
     define_native_function(vm.names.valueOf, value_of, 0, attr);
 }
 
@@ -323,6 +324,18 @@ JS_DEFINE_NATIVE_FUNCTION(DurationPrototype::to_json)
     return js_string(vm, temporal_duration_to_string(duration->years(), duration->months(), duration->weeks(), duration->days(), duration->hours(), duration->minutes(), duration->seconds(), duration->milliseconds(), duration->microseconds(), duration->nanoseconds(), "auto"sv));
 }
 
+// 7.3.24 Temporal.Duration.prototype.toLocaleString ( [ locales [ , options ] ] ), https://tc39.es/proposal-temporal/#sec-temporal.duration.prototype.tolocalestring
+// NOTE: This is the minimum toLocaleString implementation for engines without ECMA-402.
+JS_DEFINE_NATIVE_FUNCTION(DurationPrototype::to_locale_string)
+{
+    // 1. Let duration be the this value.
+    // 2. Perform ? RequireInternalSlot(duration, [[InitializedTemporalDuration]]).
+    auto* duration = TRY(typed_this_object(global_object));
+
+    // 3. Return ! TemporalDurationToString(duration.[[Years]], duration.[[Months]], duration.[[Weeks]], duration.[[Days]], duration.[[Hours]], duration.[[Minutes]], duration.[[Seconds]], duration.[[Milliseconds]], duration.[[Microseconds]], duration.[[Nanoseconds]], "auto").
+    return js_string(vm, temporal_duration_to_string(duration->years(), duration->months(), duration->weeks(), duration->days(), duration->hours(), duration->minutes(), duration->seconds(), duration->milliseconds(), duration->microseconds(), duration->nanoseconds(), "auto"sv));
+}
+
 // 7.3.25 Temporal.Duration.prototype.valueOf ( ), https://tc39.es/proposal-temporal/#sec-temporal.duration.prototype.valueof
 JS_DEFINE_NATIVE_FUNCTION(DurationPrototype::value_of)
 {

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

@@ -37,6 +37,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(abs);
     JS_DECLARE_NATIVE_FUNCTION(to_string);
     JS_DECLARE_NATIVE_FUNCTION(to_json);
+    JS_DECLARE_NATIVE_FUNCTION(to_locale_string);
     JS_DECLARE_NATIVE_FUNCTION(value_of);
 };
 

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

@@ -0,0 +1,19 @@
+describe("correct behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.Duration.prototype.toLocaleString).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        expect(new Temporal.Duration(1, 2, 3, 4, 5, 6, 7, 8, 9, 10).toLocaleString()).toBe(
+            "P1Y2M3W4DT5H6M7.00800901S"
+        );
+    });
+});
+
+describe("errors", () => {
+    test("this value must be a Temporal.Duration object", () => {
+        expect(() => {
+            Temporal.Duration.prototype.toLocaleString.call("foo");
+        }).toThrowWithMessage(TypeError, "Not an object of type Temporal.Duration");
+    });
+});