countriesForTimezone method
ISO codes whose timezone list contains timezone. Useful for
pre-selecting a country from the current system timezone. Returns an
empty list when the timezone is unknown.
Implementation
Future<List<String>> countriesForTimezone(String timezone) async {
final map = await getCountryTimezones();
final matches = <String>[];
for (final entry in map.entries) {
if (entry.value.contains(timezone)) matches.add(entry.key);
}
matches.sort();
return matches;
}