localeToVarName method
Converts a locale code to a lowerCamelCase Dart variable name.
Examples:
en_US → enUS
ar_AR → arAR
fr → fr
zh_CN → zhCN
Implementation
String localeToVarName(String locale) => locale.replaceAllMapped(
RegExp(r'_([A-Za-z]+)'),
(m) => m.group(1)!.toUpperCase(),
);