validNumber method
Implementation
bool validNumber(String ccNum) {
if (!checkLuhn) {
return true;
}
if (ccNum.length < 2) {
return false;
}
String cNum = ccNum.replaceAll(RegExp(r'\D'), '');
int mod = cNum.length % 2;
int sum = 0;
try {
for (int pos = cNum.length - 1; pos >= 0; pos--) {
int digit = int.parse(cNum[pos]);
if (pos % 2 == mod) {
digit *= 2;
if (digit > 9) {
digit -= 9;
}
}
sum += digit;
}
return sum % 10 == 0;
} on Exception {
return false;
}
}