Updating mongodb data from form using expressjs the ObjectId() make an error

the db connection is like this with ObjectId()

const mongodb = require('mongodb');
const mongoClient = mongodb.MongoClient;
const ObjectId = mongodb.ObjectId;
const url = 'mongodb://127.0.0.1:27017/';
let _db ;

const mongodbConnection = ()=>{
    mongoClient
        .connect(url, { useNewUrlParser: true })
        .then((client) => {
            _db = client.db('crud');
            console.log(`mongo db is connected and the database is ${_db}`);
        })
        .catch((error) => {
            throw console.error(err)
        });
}

const getDb= ()=>{
    return _db;
}

const _ID = (id)=>{
    return new ObjectId(id);
}

module.exports={mongodbConnection,getDb,_ID};


this for the update route from form
route.post('/edit', (req,res)=>{
    const fullname = req.body.fullname;
    const phone = req.body.phone;
    const id = JSON.stringify(req.body._id); ;
    mongodb()
      .collection("Regiter")
      .updateOne(
        { _id: _ID(id)},
        { $set: { Fullname: fullname, PhoneNumber: phone } }
      )
      .then(result => {
        res.redirect("/display");
        console.log(result.modifiedCount);
      })
      .catch(err => {
        console.log(err);
      });
}); 

the problem is when converting req.body._id to ObjectId to update