Why image not getting sent with post request?

Question

I have a form that upon submission should send the user input as post request.

The code for the form is:

 <form class="news-container" enctype="multipart/form-data">
        <h1>Post Your News</h1>
        <br/>
        <br/>
        <input type="text" name="title" class="title" placeholder="Title"/>
        <br/>
        <br/>
        <input type="textbox" name="content" class="content" placeholder="Content"/>
        <br/>
        <br/>
        <input type="file" name="thumbnail" class="thumbnail"></input>
        <br/>
        <br/>
        <select class="category" name="category">
            <option value="Political" name="Political">Political</option>
            <option value="Technical" name="'Technical">Technical</option>
            <option value="Entertainment" name="Entertainment">Entertainment</option>
            <option value="Sports" name="Sports">Sports</option>
        </select>
        <br/>
        <br/>
        <input type="checkbox" name="featured"><span>Featured Content</span></input>
        <br/>
        <br/>
        <input type="submit"  class="submit-btn"></input>
    </form>

The submit-handler for the form is:

submitbtn.addEventListener('click', (e) => {
    e.preventDefault();
    var flag=validateForm();
    console.log(flag)
    if(flag)
    {
    const data=new FormData(form);
    console.log(data)
    postData(data);    
    }
})

async function postData(data) {
    await fetch('http://localhost:5000/create', {
        method: 'POST',
        body: data
    })
}

Since I am sending files also with the form input I am using multipart/form-data as the encoding type. The code for server file which has the multer for image-upload is:

const  express=require('express');
const app= express();
const router=express.Router();
const multer=require('multer');
const storage=multer.memoryStorage();
const uploads=multer({storage});
// const News=require('./news/news');

app.use('/', router)
app.use(express.static('./public'));            //keep in mind while serving a directory , it will by default serve the index.html file in that directory.

router.post('/create',uploads.single('thumbnail'),(req,res)=>{
    console.log(req.body);
    res.send("Successful");
})

app.listen(5000,()=>{
    console.log("Server listening on 5000 port");
})

However the image is not getting sent with the post request.