LibJS+LibUnicode: Port retrieving available regional time zones to ICU

Tests/LibUnicode/TestTimeZone.cpp

@@ -49,6 +49,18 @@ TEST_CASE(available_time_zones)
     EXPECT(!time_zones.contains_slow("EAT"sv));
 }
 
+TEST_CASE(available_time_zones_in_region)
+{
+    {
+        auto time_zones = Unicode::available_time_zones_in_region("AD"sv);
+        EXPECT_EQ(time_zones, to_array({ "Europe/Andorra"_string }));
+    }
+    {
+        auto time_zones = Unicode::available_time_zones_in_region("ES"sv);
+        EXPECT_EQ(time_zones, to_array({ "Africa/Ceuta"_string, "Atlantic/Canary"_string, "Europe/Madrid"_string }));
+    }
+}
+
 TEST_CASE(resolve_primary_time_zone)
 {
     EXPECT_EQ(Unicode::resolve_primary_time_zone("UTC"sv), "Etc/UTC"sv);

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

@@ -8,9 +8,9 @@
 #include <LibJS/Runtime/Array.h>
 #include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/Intl/Locale.h>
-#include <LibTimeZone/TimeZone.h>
 #include <LibUnicode/DateTimeFormat.h>
 #include <LibUnicode/Locale.h>
+#include <LibUnicode/TimeZone.h>
 #include <LibUnicode/UnicodeKeywords.h>
 
 namespace JS::Intl {
@@ -142,12 +142,11 @@ NonnullGCPtr<Array> time_zones_of_locale(VM& vm, StringView region)
     // 3. Let region be the substring of locale corresponding to the unicode_region_subtag production of the unicode_language_id.
 
     // 4. Let list be a List of unique canonical time zone identifiers, which must be String values indicating a canonical Zone name of the IANA Time Zone Database, ordered as if an Array of the same values had been sorted using %Array.prototype.sort% using undefined as comparefn, of those in common use in region. If no time zones are commonly used in region, let list be a new empty List.
-    auto list = TimeZone::time_zones_in_region(region);
-    quick_sort(list);
+    auto list = Unicode::available_time_zones_in_region(region);
 
     // 5. Return ! CreateArrayFromList( list ).
-    return Array::create_from<StringView>(realm, list, [&vm](auto value) {
-        return PrimitiveString::create(vm, String::from_utf8(value).release_value());
+    return Array::create_from<String>(realm, list, [&vm](auto value) {
+        return PrimitiveString::create(vm, value);
     });
 }
 

Userland/Libraries/LibUnicode/TimeZone.cpp

@@ -76,26 +76,35 @@ static constexpr bool is_legacy_non_iana_time_zone(StringView time_zone)
     return legacy_zones.contains_slow(time_zone);
 }
 
+static Vector<String> icu_available_time_zones(Optional<ByteString> const& region)
+{
+    UErrorCode status = U_ZERO_ERROR;
+
+    char const* icu_region = region.has_value() ? region->characters() : nullptr;
+
+    auto time_zone_enumerator = adopt_own_if_nonnull(icu::TimeZone::createTimeZoneIDEnumeration(UCAL_ZONE_TYPE_ANY, icu_region, nullptr, status));
+    if (icu_failure(status))
+        return { "UTC"_string };
+
+    auto time_zones = icu_string_enumeration_to_list(move(time_zone_enumerator), [](char const* zone) {
+        return !is_legacy_non_iana_time_zone({ zone, strlen(zone) });
+    });
+
+    quick_sort(time_zones);
+    return time_zones;
+}
+
 Vector<String> const& available_time_zones()
 {
-    static auto time_zones = []() -> Vector<String> {
-        UErrorCode status = U_ZERO_ERROR;
-
-        auto time_zone_enumerator = adopt_own_if_nonnull(icu::TimeZone::createEnumeration(status));
-        if (icu_failure(status))
-            return { "UTC"_string };
-
-        auto time_zones = icu_string_enumeration_to_list(move(time_zone_enumerator), [](char const* zone) {
-            return !is_legacy_non_iana_time_zone({ zone, strlen(zone) });
-        });
-
-        quick_sort(time_zones);
-        return time_zones;
-    }();
-
+    static auto time_zones = icu_available_time_zones({});
     return time_zones;
 }
 
+Vector<String> available_time_zones_in_region(StringView region)
+{
+    return icu_available_time_zones(region);
+}
+
 Optional<String> resolve_primary_time_zone(StringView time_zone)
 {
     UErrorCode status = U_ZERO_ERROR;

Userland/Libraries/LibUnicode/TimeZone.h

@@ -14,6 +14,7 @@ namespace Unicode {
 
 String current_time_zone();
 Vector<String> const& available_time_zones();
+Vector<String> available_time_zones_in_region(StringView region);
 Optional<String> resolve_primary_time_zone(StringView time_zone);
 
 }