getFormattedCardNumber method
Implementation
String getFormattedCardNumber(int spacing) {
String number = cardNumber;
List<String> parts = [];
bool finish = false;
for (int i = 1; i <= number.length; i++) {
if (i % 4 == 0) {
parts.add(number.substring(i - 4, i));
finish = true;
} else {
finish = false;
}
}
if (!finish) {
int part = number.length ~/ 4;
parts.add(number.substring(part * 4));
}
String separator = '';
for (int i = 0; i < spacing; i++) separator += ' ';
return parts.join(separator);
}