LibJS: Populate pluralCategories in Intl.PluralRules.resolvedOptions

Author: https://github.com/trflynn89
Commit: https://github.com/SerenityOS/serenity/commit/f11cb7c075
Pull-request: https://github.com/SerenityOS/serenity/pull/14512
Reviewed-by: https://github.com/IdanHo
Reviewed-by: https://github.com/alimpfard
Reviewed-by: https://github.com/linusg

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

@@ -8,6 +8,7 @@
 #include <LibJS/Runtime/Array.h>
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/Intl/PluralRulesPrototype.h>
+#include <LibUnicode/PluralRules.h>
 
 namespace JS::Intl {
 
@@ -58,11 +59,14 @@ JS_DEFINE_NATIVE_FUNCTION(PluralRulesPrototype::resolved_options)
         MUST(options->create_data_property_or_throw(vm.names.maximumSignificantDigits, Value(plural_rules->max_significant_digits())));
 
     // 5. Let pluralCategories be a List of Strings containing all possible results of PluralRuleSelect for the selected locale pr.[[Locale]].
-    // FIXME: Implement this when the data is available in LibUnicode.
-    MarkedVector<Value> plural_categories { vm.heap() };
+    auto available_categories = Unicode::available_plural_categories(plural_rules->locale(), plural_rules->type());
+
+    auto* plural_categories = Array::create_from<Unicode::PluralCategory>(global_object, available_categories, [&](auto category) {
+        return js_string(vm, Unicode::plural_category_to_string(category));
+    });
 
     // 6. Perform ! CreateDataProperty(options, "pluralCategories", CreateArrayFromList(pluralCategories)).
-    MUST(options->create_data_property_or_throw(vm.names.pluralCategories, Array::create_from(global_object, plural_categories)));
+    MUST(options->create_data_property_or_throw(vm.names.pluralCategories, plural_categories));
 
     // 7. Return options.
     return options;

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

@@ -79,9 +79,29 @@ describe("correct behavior", () => {
     });
 
     test("plural categories", () => {
-        // FIXME: Write better tests when this is implemented.
-        const en = new Intl.PluralRules("en");
-        expect(en.resolvedOptions().pluralCategories).toBeDefined();
-        expect(en.resolvedOptions().pluralCategories).toEqual([]);
+        // 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(contains(enCardinal.pluralCategories, ["other", "one"])).toBeTrue();
+
+        const enOrdinal = new Intl.PluralRules("en", { type: "ordinal" }).resolvedOptions();
+        expect(enOrdinal.pluralCategories).toBeDefined();
+        expect(contains(enOrdinal.pluralCategories, ["other", "one", "two", "few"])).toBeTrue();
+
+        const gaCardinal = new Intl.PluralRules("ga", { type: "cardinal" }).resolvedOptions();
+        expect(gaCardinal.pluralCategories).toBeDefined();
+        expect(
+            contains(gaCardinal.pluralCategories, ["other", "one", "two", "few", "many"])
+        ).toBeTrue();
+
+        const gaOrdinal = new Intl.PluralRules("ga", { type: "ordinal" }).resolvedOptions();
+        expect(gaOrdinal.pluralCategories).toBeDefined();
+        expect(contains(gaOrdinal.pluralCategories, ["other", "one"])).toBeTrue();
     });
 });