Error: "TypeError: Cannot read properties of undefined (reading 'collection')"

I'm trying to retrieve data from MongoDB atlas in Visual Studio Code, but I'm getting this error:

Mongo connected
--- TypeError: Cannot read properties of undefined (reading 'collection')
    at mongoDB (mernapp/backend/db.js:10:59)
    at Object.<anonymous> (mernapp/backend/index.js:5:1)
    at Module._compile (node:internal/modules/cjs/loader:1275:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1329:10)
    at Module.load (node:internal/modules/cjs/loader:1133:32)
    at Module._load (node:internal/modules/cjs/loader:972:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:83:12)
    at node:internal/main/run_main_module:23:47

This is my db.js file:

const mongoose = require('mongoose');
const express = require("express");
const app = express();
const mongoURI = "mongodb+srv://varuag:xyz987@foodly.njjoa4i.mongodb.net/"
const mongoDB = async() => {
    try{
        mongoose.set('strictQuery',false)
        mongoose.connect(mongoURI)
        console.log('Mongo connected')
        const fetched_data = await mongoose.connection.db.collection("food_items");
        fetched_data.find({}, {projection: {}}).toArray(function(err, data){
            if(err) console.log('---', err);
            else console.log(data);
        })
    } catch(err) {
        console.log("---", err)
        process.exit();
    }
}
module.exports = mongoDB;

And, this is my index.js file:

const express = require("express");
const app = express();
const port = 5000;
const mongoDB = require("./db");
mongoDB();

app.get('/', (req, res) => {
    res.send("Hello World");
})

app.listen(port, () => {
    console.log(`The backend is listening on port ${port}`);
})

I tried changing

fetched_data.find({}) 

to

fetched_data.find({}, {projection: {}})

I'm new to this tech so I asked bard and got this as a solution but still not getting any data from database.

In your db.js file on line 8 add await as in the following code:

await mongoose.connect(mongoURI)

What's happening is you are trying to access the raw mongo instance and fetching data before the connection is made.

mongoose.connection.db //The mongodb.Db instance, set when the connection is opened

Reference: https://mongoosejs.com/docs/api/connection.html#Connection.prototype.db

UPDATE:

Regarding your comment below the following reference says toArray() does not take in any parameters.

https://www.mongodb.com/docs/manual/reference/method/cursor.toArray/#mongodb-method-cursor.toArray

You should change your code to use the following.

const data = fetched_data.find({}, {projection: {}}).toArray();
console.log(data);