isValidCardLength function

bool isValidCardLength(String? cardNumber, { String? cardBrand, })

Checks to see whether the input number is of the correct length, given the assumed brand of the card. This function does not perform a Luhn check.

@param cardNumber the card number with no spaces or dashes @param cardBrand a {@link CardBrand} used to get the correct size @return {@code true} if the card number is the correct length for the assumed brand

Implementation

bool isValidCardLength(String? cardNumber, {String? cardBrand}) {
  cardBrand ??= getPossibleCardType(cardNumber, shouldNormalize: false);
  if (cardNumber == null || StripeCard.unknown == cardBrand) {
    return false;
  }

  int length = cardNumber.length;
  switch (cardBrand) {
    case StripeCard.americanExpress:
      return length == LENGTH_AMERICAN_EXPRESS;
    case StripeCard.dinersClub:
      return length == LENGTH_DINERS_CLUB;
    default:
      return length == LENGTH_COMMON_CARD;
  }
}