getFormattedCardNumber method

String getFormattedCardNumber(
  1. int spacing
)

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);
}