I am writing a code that allows me to connect to the MongoDB database that I had made. For some reason, I am getting errors connecting my page and I don't know why. I have already looked at TypeError: connection.once(...).catch is not a function for help but that page did not answer my question. I also copied the code that my professor made and I can't seem to get it working.

This is my code:

const express = require('express');
const app = express();

const connection = require('./db/connection.js');

const dotEnv = require('dotenv').config();

connection.once('open', ()=>{
    const server = app.listen(process.env.PORT || 8080, ()=>{
    console.log("Connected and listening");
    });
});

app.use(express.static('public'));
app.use(express.urlencoded({extended:true}));

const Film = require('./models/film.js');

And this one is the connection.js file

const mongoose = require("mongoose");

let mongoDB = `name of database (this is correct, I used this to connect to a different project and it worked`;

module.exports = mongoose.connect(mongoDB);