Create validator to CNPJ using typescript

validateCNPJ.ts

const validateCNPJ = (cnpj: string): boolean => {
  if (!cnpj) return false;

  const onlyNumbersCNPJ = cnpj.replace(/[^\d]+/g, "");

  const invalidCNPJs = Array.from("0123456789").map((i) => i.repeat(14));

  if (onlyNumbersCNPJ.length !== 14 || invalidCNPJs.includes(onlyNumbersCNPJ)) {
    return false;
  }

  let size = onlyNumbersCNPJ.length - 2;
  let numbers = onlyNumbersCNPJ.substring(0, size);

  const digits = onlyNumbersCNPJ.substring(size);

  let sum = 0;
  let pos = size - 7;

  for (let i = size; i >= 1; i--) {
    sum += numbers.charAt(size - i) * pos--;
    if (pos < 2) pos = 9;
  }

  let result = sum % 11 < 2 ? 0 : 11 - (sum % 11);
  if (result !== Number(digits.charAt(0))) return false;

  size += 1;
  numbers = cnpj.substring(0, size);
  sum = 0;
  pos = size - 7;
  for (let i = size; i >= 1; i--) {
    sum += numbers.charAt(size - i) * pos--;
    if (pos < 2) pos = 9;
  }
  result = sum % 11 < 2 ? 0 : 11 - (sum % 11);
  return result === Number(digits.charAt(1));
};

export { validateCNPJ };