checkDigit method
Computes the check digit from data
.
Implementation
@override
int checkDigit(String data) {
if (data.length < 4) {
throw ArgumentError(
'Must not be null and must contain at least 4 digits',
);
}
final sum = _compute(data, hasCheckDigit: false);
return ((sum / 10).ceil() * 10) - sum;
}