isValid method

bool isValid(
  1. String ccNum
)

Implementation

bool isValid(String ccNum) {
  int qtd = initialValue.toString().length;

  if (ccNum.length < qtd) {
    return false;
  }

  int? ccInt = int.tryParse(ccNum.substring(0, qtd));

  if (ccInt == null) {
    return false;
  }

  return finalValue == null
      ? ccInt == initialValue
      : ccInt >= initialValue && ccInt <= finalValue!;
}