LibJS+LibUnicode: Designate a sort order for Intl.PluralRules categories

This is a normative change in the ECMA-402 spec. See:
62fe5db

Libraries/LibJS/Runtime/Intl/PluralRulesPrototype.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022-2023, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2022-2024, Tim Flynn <trflynn89@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -90,7 +90,8 @@ JS_DEFINE_NATIVE_FUNCTION(PluralRulesPrototype::resolved_options)
     // 3. Let options be OrdinaryObjectCreate(%Object.prototype%).
     auto options = Object::create(realm, realm.intrinsics().object_prototype());
 
-    // 4. Let pluralCategories be a List of Strings containing all possible results of PluralRuleSelect for the selected locale pr.[[Locale]].
+    // 4. Let pluralCategories be a List of Strings containing all possible results of PluralRuleSelect for the selected
+    //    locale pr.[[Locale]], sorted according to the following order: "zero", "one", "two", "few", "many", "other".
     auto available_categories = plural_rules->formatter().available_plural_categories();
 
     auto plural_categories = Array::create_from<Unicode::PluralCategory>(realm, available_categories, [&](auto category) {

Libraries/LibJS/Tests/builtins/Intl/PluralRules/PluralRules.prototype.resolvedOptions.js

@@ -79,30 +79,17 @@ describe("correct behavior", () => {
     });
 
     test("plural categories", () => {
-        // The spec doesn't dictate an order of elements, and the generated CLDR data is ordered by
-        // hash map iteration. Instead of using toEqual(), just make sure all elements are the same.
-        const contains = (actual, expected) => {
-            if (actual.length !== expected.length) return false;
-            return expected.every(e => actual.includes(e));
-        };
-
         const enCardinal = new Intl.PluralRules("en", { type: "cardinal" }).resolvedOptions();
-        expect(enCardinal.pluralCategories).toBeDefined();
+        expect(enCardinal.pluralCategories).toEqual(["one", "other"]);
-        expect(contains(enCardinal.pluralCategories, ["other", "one"])).toBeTrue();
 
         const enOrdinal = new Intl.PluralRules("en", { type: "ordinal" }).resolvedOptions();
-        expect(enOrdinal.pluralCategories).toBeDefined();
+        expect(enOrdinal.pluralCategories).toEqual(["one", "two", "few", "other"]);
-        expect(contains(enOrdinal.pluralCategories, ["other", "one", "two", "few"])).toBeTrue();
 
         const gaCardinal = new Intl.PluralRules("ga", { type: "cardinal" }).resolvedOptions();
-        expect(gaCardinal.pluralCategories).toBeDefined();
+        expect(gaCardinal.pluralCategories).toEqual(["one", "two", "few", "many", "other"]);
-        expect(
-            contains(gaCardinal.pluralCategories, ["other", "one", "two", "few", "many"])
-        ).toBeTrue();
 
         const gaOrdinal = new Intl.PluralRules("ga", { type: "ordinal" }).resolvedOptions();
-        expect(gaOrdinal.pluralCategories).toBeDefined();
+        expect(gaOrdinal.pluralCategories).toEqual(["one", "other"]);
-        expect(contains(gaOrdinal.pluralCategories, ["other", "one"])).toBeTrue();
     });
 
     test("rounding priority", () => {

Libraries/LibUnicode/NumberFormat.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2024, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2021-2024, Tim Flynn <trflynn89@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -733,6 +733,7 @@ public:
             result.append(plural_category_from_string({ category, static_cast<size_t>(length) }));
         }
 
+        quick_sort(result);
         return result;
     }
 

Libraries/LibUnicode/PluralRules.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022-2024, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2022-2024, Tim Flynn <trflynn89@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -18,12 +18,13 @@ PluralForm plural_form_from_string(StringView);
 StringView plural_form_to_string(PluralForm);
 
 enum class PluralCategory {
-    Other,
+    // NOTE: These are sorted in preferred order for Intl.PluralRules.prototype.resolvedOptions.
     Zero,
     One,
     Two,
     Few,
     Many,
+    Other,
 
     // https://unicode.org/reports/tr35/tr35-numbers.html#Explicit_0_1_rules
     ExactlyZero,