isCpf method Null safety

bool isCpf(
  1. String cpf
)

Checks if the cpf is valid.

Implementation

static bool isCpf(String cpf) {
  // if (cpf == null) {
  //   return false;
  // }

  // get only the numbers
  final numbers = cpf.replaceAll(RegExp(r'[^0-9]'), '');
  // Test if the CPF has 11 digits
  if (numbers.length != 11) {
    return false;
  }
  // Test if all CPF digits are the same
  if (RegExp(r'^(\d)\1*$').hasMatch(numbers)) {
    return false;
  }

  // split the digits
  final digits = numbers.split('').map(int.parse).toList();

  // Calculate the first verifier digit
  var calcDv1 = 0;
  for (var i in Iterable<int>.generate(9, (i) => 10 - i)) {
    calcDv1 += digits[10 - i] * i;
  }
  calcDv1 %= 11;

  final dv1 = calcDv1 < 2 ? 0 : 11 - calcDv1;

  // Tests the first verifier digit
  if (digits[9] != dv1) {
    return false;
  }

  // Calculate the second verifier digit
  var calcDv2 = 0;
  for (var i in Iterable<int>.generate(10, (i) => 11 - i)) {
    calcDv2 += digits[11 - i] * i;
  }
  calcDv2 %= 11;

  final dv2 = calcDv2 < 2 ? 0 : 11 - calcDv2;

  // Test the second verifier digit
  if (digits[10] != dv2) {
    return false;
  }

  return true;
}