isCreditCard function

bool isCreditCard(
  1. String input
)

Check if string input is a credit card or not

Implementation

bool isCreditCard(String input) {
  String sanitized = input.replaceAll(r"/[- ]+/g", '');
  if (_regExp.hasMatch(sanitized)) {
    return false;
  }
  int sum = 0;
  String digit;
  int tmpNum;
  bool shouldDouble = true;
  for (var i = sanitized.length - 1; i >= 0; i--) {
    digit = sanitized.substring(i, (i + 1));
    tmpNum = int.parse(digit, radix: 10);
    if (shouldDouble) {
      tmpNum *= 2;
      if (tmpNum >= 10) {
        sum += ((tmpNum % 10) + 1);
      } else {
        sum += tmpNum;
      }
    } else {
      sum += tmpNum;
    }
    shouldDouble = !shouldDouble;
  }

  return !!((sum % 10) == 0);
}