LibJS: Implement Intl.supportedValuesOf

This is a stage 3 ECMA-402 proposal:
https://tc39.es/proposal-intl-enumeration/

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

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/QuickSort.h>
 #include <LibJS/Runtime/Array.h>
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/Intl/AbstractOperations.h>
@@ -17,6 +18,11 @@
 #include <LibJS/Runtime/Intl/PluralRulesConstructor.h>
 #include <LibJS/Runtime/Intl/RelativeTimeFormatConstructor.h>
 #include <LibJS/Runtime/Intl/SegmenterConstructor.h>
+#include <LibJS/Runtime/Temporal/TimeZone.h>
+#include <LibUnicode/CurrencyCode.h>
+#include <LibUnicode/DateTimeFormat.h>
+#include <LibUnicode/Locale.h>
+#include <LibUnicode/NumberFormat.h>
 
 namespace JS::Intl {
 
@@ -47,6 +53,7 @@ void Intl::initialize(GlobalObject& global_object)
     define_direct_property(vm.names.Segmenter, global_object.intl_segmenter_constructor(), attr);
 
     define_native_function(vm.names.getCanonicalLocales, get_canonical_locales, 1, attr);
+    define_native_function(vm.names.supportedValuesOf, supported_values_of, 1, attr);
 }
 
 // 8.3.1 Intl.getCanonicalLocales ( locales ), https://tc39.es/ecma402/#sec-intl.getcanonicallocales
@@ -66,4 +73,85 @@ JS_DEFINE_NATIVE_FUNCTION(Intl::get_canonical_locales)
     return Array::create_from(global_object, marked_locale_list);
 }
 
+// 1.4.4 AvailableTimeZones (), https://tc39.es/proposal-intl-enumeration/#sec-availablecurrencies
+static Vector<StringView> available_time_zones()
+{
+    // 1. Let names be a List of all supported Zone and Link names in the IANA Time Zone Database.
+    auto names = TimeZone::all_time_zones();
+
+    // 2. Let result be a new empty List.
+    Vector<StringView> result;
+
+    // 3. For each element name of names, do
+    for (auto name : names) {
+        // a. Assert: ! IsValidTimeZoneName( name ) is true.
+        // b. Let canonical be ! CanonicalizeTimeZoneName( name ).
+        auto canonical = TimeZone::canonicalize_time_zone(name).value();
+
+        // c. If result does not contain an element equal to canonical, then
+        if (!result.contains_slow(canonical)) {
+            // i. Append canonical to the end of result.
+            result.append(canonical);
+        }
+    }
+
+    // 4. Sort result in order as if an Array of the same values had been sorted using %Array.prototype.sort% using undefined as comparefn.
+    quick_sort(result);
+
+    // 5. Return result.
+    return result;
+}
+
+// 2.2.2 Intl.supportedValuesOf ( key ), https://tc39.es/proposal-intl-enumeration/#sec-intl.supportedvaluesof
+JS_DEFINE_NATIVE_FUNCTION(Intl::supported_values_of)
+{
+    // 1. Let key be ? ToString(key).
+    auto key = TRY(vm.argument(0).to_string(global_object));
+
+    Span<StringView const> list;
+
+    // 2. If key is "calendar", then
+    if (key == "calendar"sv) {
+        // a. Let list be ! AvailableCalendars( ).
+        list = Unicode::get_available_calendars();
+    }
+    // 3. Else if key is "collation", then
+    else if (key == "collation"sv) {
+        // a. Let list be ! AvailableCollations( ).
+        // NOTE: We don't yet parse any collation data, but "default" is allowed.
+        static constexpr auto collations = AK::Array { "default"sv };
+        list = collations.span();
+    }
+    // 4. Else if key is "currency", then
+    else if (key == "currency"sv) {
+        // a. Let list be ! AvailableCurrencies( ).
+        list = Unicode::get_available_currencies();
+    }
+    // 5. Else if key is "numberingSystem", then
+    else if (key == "numberingSystem"sv) {
+        // a. Let list be ! AvailableNumberingSystems( ).
+        list = Unicode::get_available_number_systems();
+    }
+    // 6. Else if key is "timeZone", then
+    else if (key == "timeZone"sv) {
+        // a. Let list be ! AvailableTimeZones( ).
+        static auto time_zones = available_time_zones();
+        list = time_zones.span();
+    }
+    // 7. Else if key is "unit", then
+    else if (key == "unit"sv) {
+        // a. Let list be ! AvailableUnits( ).
+        static auto units = sanctioned_simple_unit_identifiers();
+        list = units.span();
+    }
+    // 8. Else,
+    else {
+        // a. Throw a RangeError exception.
+        return vm.throw_completion<RangeError>(global_object, ErrorType::IntlInvalidKey, key);
+    }
+
+    // 9. Return ! CreateArrayFromList( list ).
+    return Array::create_from<StringView>(global_object, list, [&](auto value) { return js_string(vm, value); });
+}
+
 }