validate method

@override String? validate(String? input)

Implementation

@override
String? validate(String? input) {
  if (input == null || input.trim().isEmpty) {
    return kOtpRequiredError;
  }
  if (input.length != length) {
    return kOtpLengthFormat.replaceFirst('%d', length.toString());
  }
  if (!RegExp(patternOtp).hasMatch(input)) {
    return kOtpNumericError;
  }
  return null;
}