function accountNumberValidator(accountNumber, countryCode) {
  let copy = accountNumber.replace(/[^0-9]+/g, '');
  const weights = [
    1,
    10,
    3,
    30,
    9,
    90,
    27,
    76,
    81,
    34,
    49,
    5,
    50,
    15,
    53,
    45,
    62,
    38,
    89,
    17,
    73,
    51,
    25,
    56,
    75,
    71,
    31,
    19,
    93,
    57,
  ];
  const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';

  if (countryCode.split('').some(char => !alphabet.includes(char))) return false;

  const countryCodeDigits = countryCode
    .toUpperCase()
    .split('')
    .map(char => alphabet.indexOf(char) + 10)
    .join('');

  if (copy.length !== 26) return false;

  copy += countryCodeDigits;
  copy = copy.substr(2) + copy.substr(0, 2);
  copy = copy.split('').reverse();

  return copy.reduce((accumulator, current, i) => accumulator + current * weights[i], 0) % 97 === 1;
}