How to add 'createdBy' field in appointments?

app.post("/BatchData", (req, res) => {
    console.log(req.body);
    var eventData = [];
    if (req.body.action == "insert" || (req.body.action == "batch" && req.body.added.length > 0)) {
        (req.body.action == "insert") ? eventData.push(req.body.value) : eventData = req.body.added;
        for (var i = 0; i < eventData.length; i++) {
            var sdate = new Date(eventData[i].StartTime);
            var edate = new Date(eventData[i].EndTime);
            eventData[i].StartTime = (new Date(+sdate - (sdate.getTimezoneOffset() * 60000)));
            eventData[i].EndTime = (new Date(+edate - (edate.getTimezoneOffset() * 60000)));
            eventData[i].CreatedBy =  //here i want to add the users emailadress from the token;
            dbo.collection('ScheduleData').insertOne(eventData[i]);
        }
    }

I tried to add the token middleware to the function, like this:

app.post("/BatchData", authRequired, (req, res) => {

but as soon i add that extra argument, it stops retrieving the appointments, without any error message.  This is my authRequired function:

const User = require('../models/user');
const jwt = require('jsonwebtoken');
const config = require('../config/database')

function authRequired(req, res, next) {
    const token = req.get("authorization");
    if (!token) {
        res.json({ success: false, message: "No token provided" });
    } else {
        jwt.verify(token, config.secret, (err, decoded) => {
            if (err) {
                res.json({ success: false, message: "Token is invalid" + err });
            } else {
                req.decoded = decoded;
                next();
            }
        });
    }
}

module.exports = {
    authRequired: authRequired
};

Another option would be to send the emailaddress via the frontend. How do I add a custom field 'createdBy' (without any graphical input elements) to send a value from my component along with the appointment data in the Mongo collection? Do I add that in the onPopUpOpen() function?

Can you maybe help me on how to put users emailadres there at the 'createdBy' field? I retrieve the users info by this code:

ngOnInit() {
  this.auth.getProfile().subscribe((profile : any) => {
    this.userName = profile.user.username;
    this.email = profile.user.email;
    console.log(profile.user.email)
  })
 }

If you need any more info, please let me know

Thanks in advance