Validação de CPF

cpf-validator.ts

function validaCPF(cpf: string): boolean {
  cpf = cpf.replace(/\D/g, '');

  if (cpf.length !== 11 || /^(\d)\1+$/.test(cpf)) return false;

  const calcularDigito = (base: number) => {
    let soma = 0;
    for (let i = 0; i < base - 1; i++) {
      soma += parseInt(cpf.charAt(i)) * (base - i);
    }
    const resto = (soma * 10) % 11;
    return resto >= 10 ? 0 : resto;
  };

  const digito1 = calcularDigito(10);
  const digito2 = calcularDigito(11);

  return cpf.charAt(9) === digito1.toString() && cpf.charAt(10) === digito2.toString();
}