LibJS: Implement Intl.getCanonicalLocales

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -175,6 +175,7 @@ namespace JS {
     P(get)                                   \
     P(getBigInt64)                           \
     P(getBigUint64)                          \
+    P(getCanonicalLocales)                   \
     P(getDate)                               \
     P(getDay)                                \
     P(getFloat32)                            \

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

@@ -4,7 +4,9 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <LibJS/Runtime/Array.h>
 #include <LibJS/Runtime/GlobalObject.h>
+#include <LibJS/Runtime/Intl/AbstractOperations.h>
 #include <LibJS/Runtime/Intl/DisplayNamesConstructor.h>
 #include <LibJS/Runtime/Intl/Intl.h>
 
@@ -27,6 +29,27 @@ void Intl::initialize(GlobalObject& global_object)
 
     u8 attr = Attribute::Writable | Attribute::Configurable;
     define_direct_property(vm.names.DisplayNames, global_object.intl_display_names_constructor(), attr);
+
+    define_native_function(vm.names.getCanonicalLocales, get_canonical_locales, 1, attr);
+}
+
+// 8.3.1 Intl.getCanonicalLocales ( locales ), https://tc39.es/ecma402/#sec-intl.getcanonicallocales
+JS_DEFINE_NATIVE_FUNCTION(Intl::get_canonical_locales)
+{
+    auto locales = vm.argument(0);
+
+    // 1. Let ll be ? CanonicalizeLocaleList(locales).
+    auto locale_list = canonicalize_locale_list(global_object, locales);
+    if (vm.exception())
+        return {};
+
+    MarkedValueList marked_locale_list { vm.heap() };
+    marked_locale_list.ensure_capacity(locale_list.size());
+    for (auto& locale : locale_list)
+        marked_locale_list.append(js_string(vm, move(locale)));
+
+    // 2. Return CreateArrayFromList(ll).
+    return Array::create_from(global_object, marked_locale_list);
 }
 
 }

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

@@ -17,6 +17,9 @@ public:
     explicit Intl(GlobalObject&);
     virtual void initialize(GlobalObject&) override;
     virtual ~Intl() override = default;
+
+private:
+    JS_DECLARE_NATIVE_FUNCTION(get_canonical_locales);
 };
 
 }