verify result is undefined

[NathanHazout]

Hello,

Given this snippet of code:

let myCertificatePath = path.join(__dirname, 'nathan.crt');
let caBundlePath = path.join(__dirname, 'ca-bundle.pem');
x509.verify(myCertificatePath, caBundlePath, function(err, result){
    console.log("finished validation");
    if(err){
        console.log("validation error");
        console.log(err);
    } else {
        console.log("validation result");
        console.log(result);
    }
});

My console log prints:

validation result
undefined

What does it mean? What could lead result to be undefined, without any errors?