How to read the value or a field in mongodb atlas collection document and display results as json in postman using javascript,express and nodejs

Question

How do I write a query for mongodb atlas to read a field form a document of a collection in mongodb atlas database and display a result in postman as javascript?

I've tried using projections and toArray() and forEach() methods. It displays {} . Not sure what am doing wrong. Need to display an information.

MongoClient.connect(uri, { useNewUrlParser: true }, (error, client, db) =>  {
    if(error) {
        console.log('Error occurred while connecting to MongoDB Atlas... instance due to:\n',error);
    } else {
        //declare database instance
        db = client.db('v');
        //show database connection
        console.log("Database connection established!");
        console.log("Connected to `" + dbname + "!");                      
        //retrieves balance
        const cursor = db.collection('users').find({}).toArray();
        console.log("user" + " " + phoneNumber + " " + " balance is:" ); 

        //json response message           
        res.status(200).json({ balance: cursor });
    }
});

This is the result

{
    "balance": {}
}

Answer 1

The find() of mongodb is an asynchronous method, so you have to pass a callback function to get the data. Try the below code:

MongoClient.connect(uri, {
    useNewUrlParser: true
}, (error, client) => {
    if (error) {
        console.log('Error occurred while connecting to MongoDB Atlas... instance due to:\n', error);
        return res.status(500).json({
            error: err
        });
    } else {
        //declare database instance
        const db = client.db('v');

        //show database connection
        console.log("Database connection established!");
        console.log("Connected to `" + dbname + "!");

        const collection = db.collection('users');

        //retrieves balance
        collection.find().toArray((err, cursor) => {
            if (err) {
                console.log(err);
                return res.status(500).json({
                    error: err
                });
            }
            console.log(cursor);
            //json response message           
            return res.status(200).json({
                balance: cursor
            });
        });
    }
});

Hope this helps :)