validateLangCode function

String validateLangCode(
  1. String code
)

Validates the given code as a supported language code.

Converts code to lowercase and checks if it exists in supportedLangCodes. If the code is invalid, throws UnsupportedLanguageException.

Example:

final lang = validateLangCode('Ne'); // returns 'ne'
validateLangCode('xx'); // throws UnsupportedLanguageException

code: The language code to validate (case-insensitive).

Returns the normalized (lowercase) version of the code if valid.

Throws UnsupportedLanguageException if the code is not supported.

Implementation

String validateLangCode(String code) {
  final normalized = code.toLowerCase();
  if (!supportedLangCodes.contains(normalized)) {
    throw UnsupportedLanguageException(code);
  }
  return normalized;
}