iscpf = (cpf) => {
cpf = cpf.replace(/[^\d]+/g, '');
if(cpf.length !== 11 || /^(\d)\1+$/.test(cpf))
return false;
let soma = 0,
resto;
for (var i = 1; i <= 9; i++)
soma = soma + parseInt(cpf.substring(i-1, i)) * (11 - i);
resto = (soma * 10) % 11;
if((resto == 10) || (resto == 11))
resto = 0;
if(resto != parseInt(cpf.substring(9, 10)) )
return false;
soma = 0;
for(var i = 1; i <= 10; i++)
soma = soma + parseInt(cpf.substring(i-1, i)) * (12 - i);
resto = (soma * 10) % 11;
if((resto == 10) || (resto == 11))
resto = 0;
if(resto != parseInt(cpf.substring(10, 11) ) )
return false;
return true;
}