LibJS: Implement Intl.ListFormat.prototype.formatToParts

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -168,6 +168,7 @@ namespace JS {
     P(fontsize)                              \
     P(forEach)                               \
     P(format)                                \
+    P(formatToParts)                         \
     P(fractionalSecondDigits)                \
     P(freeze)                                \
     P(from)                                  \

Userland/Libraries/LibJS/Runtime/Intl/ListFormatPrototype.cpp

@@ -9,6 +9,7 @@
 #include <AK/TypeCasts.h>
 #include <AK/Variant.h>
 #include <AK/Vector.h>
+#include <LibJS/Runtime/Array.h>
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/Intl/AbstractOperations.h>
 #include <LibJS/Runtime/Intl/ListFormat.h>
@@ -191,6 +192,42 @@ static String format_list(ListFormat const& list_format, Vector<String> const& l
     return result.build();
 }
 
+// 13.1.4 FormatListToParts ( listFormat, list ), https://tc39.es/ecma402/#sec-formatlisttoparts
+static Array* format_list_to_parts(GlobalObject& global_object, ListFormat const& list_format, Vector<String> const& list)
+{
+    auto& vm = global_object.vm();
+
+    // 1. Let parts be CreatePartsFromList(listFormat, list).
+    auto parts = create_parts_from_list(list_format, list);
+
+    // 2. Let result be ArrayCreate(0).
+    auto result = Array::create(global_object, 0);
+
+    // 3. Let n be 0.
+    size_t n = 0;
+
+    // 4. For each Record { [[Type]], [[Value]] } part in parts, do
+    for (auto const& part : parts) {
+        // a. Let O be OrdinaryObjectCreate(%Object.prototype%).
+        auto* object = Object::create(global_object, global_object.object_prototype());
+
+        // b. Perform ! CreateDataPropertyOrThrow(O, "type", part.[[Type]]).
+        object->create_data_property_or_throw(vm.names.type, js_string(vm, part.type));
+
+        // c. Perform ! CreateDataPropertyOrThrow(O, "value", part.[[Value]]).
+        object->create_data_property_or_throw(vm.names.value, js_string(vm, part.value));
+
+        // d. Perform ! CreateDataPropertyOrThrow(result, ! ToString(n), O).
+        result->create_data_property_or_throw(n, object);
+
+        // e. Increment n by 1.
+        ++n;
+    }
+
+    // 5. Return result.
+    return result;
+}
+
 // 13.1.5 StringListFromIterable ( iterable ), https://tc39.es/ecma402/#sec-createstringlistfromiterable
 static Vector<String> string_list_from_iterable(GlobalObject& global_object, Value iterable)
 {
@@ -263,6 +300,7 @@ void ListFormatPrototype::initialize(GlobalObject& global_object)
 
     u8 attr = Attribute::Writable | Attribute::Configurable;
     define_native_function(vm.names.format, format, 1, attr);
+    define_native_function(vm.names.formatToParts, format_to_parts, 1, attr);
 }
 
 // 13.4.3 Intl.ListFormat.prototype.format ( list ), https://tc39.es/ecma402/#sec-Intl.ListFormat.prototype.format
@@ -286,4 +324,24 @@ JS_DEFINE_NATIVE_FUNCTION(ListFormatPrototype::format)
     return js_string(vm, move(formatted));
 }
 
+// 13.4.4 Intl.ListFormat.prototype.formatToParts ( list ), https://tc39.es/ecma402/#sec-Intl.ListFormat.prototype.formatToParts
+JS_DEFINE_NATIVE_FUNCTION(ListFormatPrototype::format_to_parts)
+{
+    auto list = vm.argument(0);
+
+    // 1. Let lf be the this value.
+    // 2. Perform ? RequireInternalSlot(lf, [[InitializedListFormat]]).
+    auto* list_format = typed_this(global_object);
+    if (vm.exception())
+        return {};
+
+    // 3. Let stringList be ? StringListFromIterable(list).
+    auto string_list = string_list_from_iterable(global_object, list);
+    if (vm.exception())
+        return {};
+
+    // 4. Return FormatListToParts(lf, stringList).
+    return format_list_to_parts(global_object, *list_format, string_list);
+}
+
 }

Userland/Libraries/LibJS/Runtime/Intl/ListFormatPrototype.h

@@ -20,6 +20,7 @@ public:
 
 private:
     JS_DECLARE_NATIVE_FUNCTION(format);
+    JS_DECLARE_NATIVE_FUNCTION(format_to_parts);
 };
 
 }