function sendEmail(userEmail, htmlString, requestSnap, FIREBASE_WEB) {

 fileName ="test.pdf";
 folderName = "./" + uuid.v4();
 mkdirp(folderName, function(err) {
    if (err) console.error(err)
        else console.log(folderName + ' folder created!')
    });

pdf.create(htmlString + userEmail, options).toFile(folderName + '/' + fileName, function(err, res) { // if the file doesnt exist it will be created
    if (err) return console.log(err);
    console.log(res);
});

var transporter = nodemailer.createTransport(smtpTransport({
    service: 'Gmail',
    auth: {
        user: '...',
        pass: '...'
    }
}));

console.log("nPATH " + folderName + "/" + fileName);

var mailOptions = {
    from: 'marija.lukaroska.cw@gmail.com',
    to: userEmail,
    subject: 'So mail vo pdf-ot',
    text: 'Hellow',
    attachments: [{
        path: folderName + "/" + fileName
    }]
};

transporter.sendMail(mailOptions, function(error, info) {
    if (error) {
        console.log("ERROR kkkk " + error);
    } else {
        console.log('Email sent: ' + info.response);
        console.log("REQUEST SNAP " + JSON.stringify(requestSnap));
    }

    deleteFolderRecursive(folderName);
});