MongoAtlas Error: invalid schema, expected mongodb - node.js

Question

I am trying to connect to MongoAtlas, however I keep getting
Error: invalid schema, expected mongodb
It seems to be that I can connect, but it cannot get my db from MongoAtlas. My try catch error returns me (node:5964) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'collection' of undefined
.env
PORT = 9055
MONGO_URI =mongodb+srv://<my-db-username>:<my-password>#cluster0.vossd.mongodb.net/<db-name>?
retryWrites=true&w=majority
server.js
require('dotenv').config();
const port = Number.parseInt(process.env.PORT, 10);
const mongoUri = process.env.MONGO_URI;
const {MongoClient} = require('mongodb');
const express = require('express');
const Application = require('./application');
const application = Application();
const Health = require('./health');
const Product = require('./product');
const Cart = require('./cart');
const Order = require('./order');
async function main() {
let db;
try {
db = await MongoClient.connect(mongoUri);
console.log(db)
} catch (err) {
console.log(err);
}
application.use('/health', Health());
application.use('/product', Product(db));
application.use('/cart', Cart(db));
application.use('/order', Order(db));
const server = application.listen(port, () => {
const host = server.address().address;
const port = server.address().port;
console.log(`Shopping website server up and running, listening at http://${host}:${port}`);
});
}
main();
Everything works fine when I'm connected to my local db, so I'm unsure as to what I'm doing incorrectly. Any advice is much appreciated. Thank you!

Answer 1

This cannot read property 'collection' of undefined might be misleading as you have caught the error happening on connection. Hence db is null so if you access collection it will give this error. Below is the sample code from Mongo Atlas.
const MongoClient = require('mongodb').MongoClient;
const uri = "mongodb+srv://<username>:<password>#test.w7hgn.mongodb.net/<dbname>?retryWrites=true&w=majority";
const client = new MongoClient(uri, { useNewUrlParser: true }); // <-- note the option
client.connect(err => {
const collection = client.db("test").collection("devices");
// perform actions on the collection object
client.close();
});