Connecting to local mongodb server using nodejs

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1

Hello! I am a beginner. I recently started node.js tutorial on w3schools on node.js. I stumbled on the place where I have to connect to mongodb. So, I created my project folder, changed to it, ran npm init, installed mongodb. Then I had to create a .js file with the following content:

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/mydb";

MongoClient.connect(url, function(err, db) {
  if (err) throw err;
  console.log("Database created!");
  db.close();
});

But when I run it, the black cursor moves on a new line in the terminal and blinks for several seconds. It just hangs there and I get no error messages nor command prompt. After a few minutes I choose to Ctrl+C to stop it. I tried to use 127.0.0.1 instead of localhost, but that didn’t work either.
So, I started to read the doc on mongodb.com, which suggests using this code:

const { MongoClient, ServerApiVersion } = require("mongodb");
// Replace the placeholder with your Atlas connection string
const uri = "mongodb://localhost:27017";
// Create a MongoClient with a MongoClientOptions object to set the Stable API version
const client = new MongoClient(uri,  {
        serverApi: {
            version: ServerApiVersion.v1,
            strict: true,
            deprecationErrors: true,
        }
    }
);
async function run() {
  try {
    // Connect the client to the server (optional starting in v4.7)
    await client.connect();
    // Send a ping to confirm a successful connection
    await client.db("admin").command({ ping: 1 });
    console.log("Pinged your deployment. You successfully connected to MongoDB!");
  } finally {
    // Ensures that the client will close when you finish/error
    await client.close();
  }
}
run().catch(console.dir);

I am not aware of what all of this code does but at least it prints that it successfully connected and there is command prompt after running it.
I start my server by running: sudo systemctl start mongod
I can check that it is running by: sudo systemctl status mongod
I use Debian 11
I have mongosh installed, it says:
`Connecting to: mongodb://127.0.0.1:27017/?directConnection=true&serverSelectionTimeoutMS=2000&appName=mongosh+1.10.1
Using MongoDB: 6.0.8
Using Mongosh: 1.10.1

For mongosh info see: https://docs.mongodb.com/mongodb-shell/
`
My question is firstly what is wrong with the w3schools tutorial code? I could take the latter from mongodb docs but it looks bulky. I wanted to start small and I just can’t get why it doesn’t work. Thanks.

2

Is this not as your code is not closing the connection, but the longer sample code is?

    await client.close();
3

Sounds reasonable. How do I check it. The line is present though.

4

Actually…testing locally it seems the callback is not hit…the w3schools tutorial does not seem to work, which is weird, as their example are normally good.

5

Yes, I like their tutorials.

6

Sure someone with more experience of this can explain why the callback is not working as lots of example I can see online do the same.

Looking in the release notes, 4.7 of the driver made it optional to call the connect method:

I also saw mentions of deprecating the callbacks in favour of the promise returns, which explains the style in the second example.