geracpf.js

function geraCpf() {
	const cpf = [
		geraInt(0, 9),
		geraInt(0, 9),
        geraInt(0, 9),
        geraInt(0, 9),
        geraInt(0, 9),
        geraInt(0, 9),
        geraInt(0, 9),
        geraInt(0, 9),
        geraInt(0, 9)].join('');
	const dv1 = calcDvMod11(cpf);
	const dv2 = calcDvMod11(`${cpf}${dv1}`);
	
    return `${cpf}${dv1}${dv2}`;
}

function geraInt(min, max) {
	return Math.floor(Math.random() * max) + min;
}

function calcDvMod11(str) {
    const tokens = str.split('');
	const mod = 11;
    let i = tokens.length + 1;
    let sum = 0;
    
    for (let token of tokens) {
        sum += parseInt(token, 10) * i--;
    }
    
    const resto = sum % mod;
    if (resto < 2) {
        return 0;
    }
    
    return mod - resto;
}