code: function isCreditCard(str) {
    (0, _assertString.default)(str);
    var sanitized = str.replace(/[- ]+/g, '');
  
    if (!creditCard.test(sanitized)) {
      return false;
    }
  
    var sum = 0;
    var digit;
    var tmpNum;
    var shouldDouble;
  
    for (var i = sanitized.length - 1; i >= 0; i--) {
      digit = sanitized.substring(i, i + 1);
      tmpNum = parseInt(digit, 10);
  
      if (shouldDouble) {
        tmpNum *= 2;
  
        if (tmpNum >= 10) {
          sum += tmpNum % 10 + 1;
        } else {
          sum += tmpNum;
        }
      } else {
        sum += tmpNum;
      }
  
      shouldDouble = !shouldDouble;
    }
  
    return !!(sum % 10 === 0 ? sanitized : false);
  }
docs: /* eslint-enable max-len