Form POST request, not working. Undefined in Server (HTML,JS,EXPRESS,NODE,MONGODB)

Im working in an application with a front and a back end, my back end written in nodejs, using express, multer and mongoose, is working pretty fine when i send data through postman, but as soon as i try the same request in my client made with html,css and vanilla javascript, it doesnt work, it gives me the following error:

TypeError: Cannot read property ‘path’ of undefined (which is pointing towards my network file that manages connections for a specific entity).

Despite the error mentioned above, i’ve been trying to send a file and a string from the form in html to the network file in my node server, but i keep getting the same 2 or so errors in terminal.

Here is some code so you can understand better.

server.js (main entry point)

const express = require('express');
const app = express();
const server = require('http').Server(app);
const path = require('path');

const cors = require('cors');
const bodyParser = require('body-parser');
const db = require('./db');
const router = require('./network/routes');
const config = require('./config');

db(config.dbUrl);
app.use(cors());
app.use(express.json());
app.use(bodyParser.urlencoded({ extended: true }));

app.use(`${config.publicRoute}`, express.static(path.join(__dirname, 'public')));
server.listen(config.port, function() {});
console.log(`Application listen on ${config.host}${config.port}`);
router(app);

network.js (file that manages connections for “banner” entity)

const express = require('express');
const multer = require('multer');
const router = express.Router();
const response = require('../../network/response');
const controller = require('./controller');
const path = require('path');
const storage = multer.diskStorage({
    destination: function(req, file, cb) {
        cb(null, path.join(__dirname, '../../public/files'))
    },
    filename: function(req, file, cb) {
        cb(null, path.extname(file.originalname))
    }
})
const upload = multer({ storage: storage })

router.post('/', upload.single('file'), function(req, res) {

    console.log(req.body);
    controller.addBanner(req.body.name, req.file, req.file.path)
        .then((fullMessage) => {
            response.success(req, res, fullMessage, 201);
        })
        .catch(e => {
            response.error(req, res, 'Unexpected error', "Simulated Error", 400, e);
        });
});

router.get('/', function(req, res) {
    controller.getBanners()
        .then((banners) => {
            response.success(req, res, banners, 200);
        })
        .catch(e => {
            response.error(req, res, 'Internal Error', 500, e);
        })
});

router.delete('/:id', function(req, res) {
    controller.deleteBanner(req.params.id)
        .then(() => {
            response.success(req, res, `Imagen con id: ${req.params.id} ,eliminada`, 200);
        })
        .catch(e => {
            response.error(req, res, 'Internal Error', 500, e);
        })
});

module.exports = router;

panel.html (where the form that supposedly sends the post request lies)

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- <meta http-equiv="Content-Security-Policy" content="default-src https://cdn.example.net; child-src 'none'; object-src 'none'"> -->
    <link rel="stylesheet" type="text/css" href="css/panel-style.css">
    <script defer src="panel-script.js"></script>
    <title>Panel de Control</title>
</head>

<body>
    <header>
        <img src="assets/mrvapeslogo.png" alt="mrvapes logo">
        <a href="index.html"></a>
    </header>
    <section>
        <form accept-charset="UTF-8" enctype="multipart/form-data" action="../components/banner/network.js" autocomplete="off" method="GET" target="_blank">
            <label for="user">Banners Activos</label><br/>
            <ul class="files-container">

            </ul>
        </form>
        <form accept-charset="UTF-8" enctype="multipart/form-data" action="http://localhost:3000/banner" autocomplete="off" method="POST" target="_blank">
            <div class="container">
                <div class="button-wrap">
                    <!-- <label class="button" for="upload">Subir</label> -->
                    <input type="text" id="name" placeholder="Nombre de Archivo" value="" name="name" required>
                    <input id="image" value="Subir" placeholder="Subir Archivo" type="file" required>
                    <button id="upload" name="send-post--request" value="post-request" type="submit">Enviar</button>
                    <!-- <input id="upload" type=" submit " value="Enviar " onclick="submit() "> -->
                </div>
            </div>
        </form>
    </section>
</body>

panel-script.js (client-side file that manages the logic for the http request)

const upload = document.getElementById("upload");
const image = document.getElementById("image");
const title = document.getElementById("name");

upload.addEventListener("click", (e) => {
    console.log('im in bro');
    e.preventDefault();
    var xhr = new XMLHttpRequest();
    xhr.onreadystatechange = function() {
        if (xhr.readyState === 4) {
            alert(xhr.response);
        }
    }
    xhr.open("POST", 'http://localhost:3000/banner', true);
    //xhr.setRequestHeader("Accept", "multipart/form-data");
    //xhr.setRequestHeader('Content-Type', 'multipart/form-data');
    var fileSent = {
        "name": title,
        "file": image
    };
    console.log(fileSent);
    xhr.send(fileSent);
    alert('Subida exitosa!');
})


function retrieve() {
    var xhr = new XMLHttpRequest();
    xhr.onreadystatechange = function() {
        if (xhr.readyState === 4) {
            alert(xhr.response);
        }
    }
    xhr.open('get', 'http://localhost:3000/banner', true);
    xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
    xhr.send();
}

I’m all ears towards your suggestions, thanks in advance fellow developers.