CPF validator using typescript | validate CPF using typescript

validateCPF.ts

const validateCPF = (cpf: string): boolean => {
  if (!cpf) return false;

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

  const invalidCPFs = Array.from("0123456789").map((i) => i.repeat(11));

  if (onlyNumbersCPF.length !== 11 || invalidCPFs.includes(onlyNumbersCPF)) {
    return false;
  }

  let sum = 0;
  let rest;

  for (let i = 1; i <= 9; i++) {
    sum += parseInt(onlyNumbersCPF.substring(i - 1, i)) * (11 - i);
  }

  rest = (sum * 10) % 11;

  if (rest === 10 || rest === 11) {
    rest = 0;
  }

  if (rest !== parseInt(onlyNumbersCPF.substring(9, 10))) {
    return false;
  }

  sum = 0;

  for (let i = 1; i <= 10; i++) {
    sum += parseInt(onlyNumbersCPF.substring(i - 1, i)) * (12 - i);
  }

  rest = (sum * 10) % 11;

  if (rest === 10 || rest === 11) {
    rest = 0;
  }

  if (rest !== parseInt(onlyNumbersCPF.substring(10, 11))) {
    return false;
  }

  return true;
};

export { validateCPF };