Node.js password hash and salt questions

I'm implementing an authenticated web app and I've some questions about username and password storage.

There is no possibility of implementing any TFA method and I need some expert advice about the way I'm saving in the database the hashed password and the salt.

These are my JS functions to generate the salt and the way I hash the password:

createSalt = function() {
var len = 30;
return crypto.randomBytes(Math.ceil(len * 3 / 4))
    .toString('base64') // convert to base64 format
    .slice(0, len) // return required number of characters
    .replace(/\+/g, '0') // replace '+' with '0'
    .replace(/\//g, '0'); // replace '/' with '0'
}

hashPassword = function(password, salt) {
    var hash = crypto.createHash('sha256');
    hash.update(password || "");
    hash.update(salt || "");
    return hash.digest('hex');
}

Any comment or improvement?

Thanks in advice.

via Pablo