LibJS: Implement Intl.Locale.prototype.minimize

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -289,6 +289,7 @@ namespace JS {
     P(millisecond)                           \
     P(milliseconds)                          \
     P(min)                                   \
+    P(minimize)                              \
     P(minute)                                \
     P(minutes)                               \
     P(month)                                 \

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

@@ -42,6 +42,7 @@ void LocalePrototype::initialize(GlobalObject& global_object)
 
     u8 attr = Attribute::Writable | Attribute::Configurable;
     define_native_function(vm.names.maximize, maximize, 0, attr);
+    define_native_function(vm.names.minimize, minimize, 0, attr);
     define_native_function(vm.names.toString, to_string, 0, attr);
 
     // 14.3.2 Intl.Locale.prototype[ @@toStringTag ], https://tc39.es/ecma402/#sec-Intl.Locale.prototype-@@tostringtag
@@ -79,6 +80,26 @@ JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::maximize)
     return Locale::create(global_object, *locale);
 }
 
+// 14.3.4 Intl.Locale.prototype.minimize ( ), https://tc39.es/ecma402/#sec-Intl.Locale.prototype.minimize
+JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::minimize)
+{
+    // 1. Let loc be the this value.
+    // 2. Perform ? RequireInternalSlot(loc, [[InitializedLocale]]).
+    auto* locale_object = typed_this(global_object);
+    if (!locale_object)
+        return {};
+
+    auto locale = Unicode::parse_unicode_locale_id(locale_object->locale());
+    VERIFY(locale.has_value());
+
+    // 3. Let minimal be the result of the Remove Likely Subtags algorithm applied to loc.[[Locale]]. If an error is signaled, set minimal to loc.[[Locale]].
+    if (auto minimal = Unicode::remove_likely_subtags(locale->language_id); minimal.has_value())
+        locale->language_id = minimal.release_value();
+
+    // 4. Return ! Construct(%Locale%, minimal).
+    return Locale::create(global_object, *locale);
+}
+
 // 14.3.5 Intl.Locale.prototype.toString ( ), https://tc39.es/ecma402/#sec-Intl.Locale.prototype.toString
 JS_DEFINE_NATIVE_FUNCTION(LocalePrototype::to_string)
 {

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

@@ -20,6 +20,7 @@ public:
 
 private:
     JS_DECLARE_NATIVE_FUNCTION(maximize);
+    JS_DECLARE_NATIVE_FUNCTION(minimize);
     JS_DECLARE_NATIVE_FUNCTION(to_string);
 
     JS_DECLARE_NATIVE_GETTER(base_name);

Userland/Libraries/LibJS/Tests/builtins/Intl/Locale/Locale.prototype.minimize.js

@@ -0,0 +1,34 @@
+test("length is 0", () => {
+    expect(Intl.Locale.prototype.minimize).toHaveLength(0);
+});
+
+test("normal behavior", () => {
+    expect(new Intl.Locale("en").minimize().toString()).toBe("en");
+
+    expect(new Intl.Locale("en-Latn").minimize().toString()).toBe("en");
+    expect(new Intl.Locale("ar-Arab").minimize().toString()).toBe("ar");
+    expect(new Intl.Locale("en-US").minimize().toString()).toBe("en");
+    expect(new Intl.Locale("en-GB").minimize().toString()).toBe("en-GB");
+
+    expect(new Intl.Locale("en-Latn-US").minimize().toString()).toBe("en");
+    expect(new Intl.Locale("en-Shaw-GB").minimize().toString()).toBe("en-Shaw");
+    expect(new Intl.Locale("en-Arab-US").minimize().toString()).toBe("en-Arab");
+    expect(new Intl.Locale("en-Latn-GB").minimize().toString()).toBe("en-GB");
+    expect(new Intl.Locale("en-Latn-FR").minimize().toString()).toBe("en-FR");
+
+    expect(new Intl.Locale("it-Kana-CA").minimize().toString()).toBe("it-Kana-CA");
+
+    expect(new Intl.Locale("th-Thai-TH").minimize().toString()).toBe("th");
+    expect(new Intl.Locale("es-Latn-419").minimize().toString()).toBe("es-419");
+    expect(new Intl.Locale("ru-Cyrl-RU").minimize().toString()).toBe("ru");
+    expect(new Intl.Locale("de-Latn-AT").minimize().toString()).toBe("de-AT");
+    expect(new Intl.Locale("bg-Cyrl-RO").minimize().toString()).toBe("bg-RO");
+    expect(new Intl.Locale("und-Latn-AQ").minimize().toString()).toBe("und-AQ");
+});
+
+test("keywords are preserved", () => {
+    expect(new Intl.Locale("en-Latn-US-u-ca-abc").minimize().toString()).toBe("en-u-ca-abc");
+    expect(new Intl.Locale("en-Latn-US", { calendar: "abc" }).minimize().toString()).toBe(
+        "en-u-ca-abc"
+    );
+});