MongoDB connection with mongodb driver in Node.js

Introduction

Connecting to MongoDB lets your Node.js app store and get data easily.

When you want to save user info from a website.

When you need to read data from a database to show on a page.

When you want to update or delete records in your app.

When you build a backend that talks to a database.

When you want to keep data safe and organized.

Syntax

Node.js

import { MongoClient } from 'mongodb';

const uri = 'your_mongodb_connection_string';
const client = new MongoClient(uri);

async function run() {
  try {
    await client.connect();
    console.log('Connected to MongoDB');
    // Use the client here
  } finally {
    await client.close();
  }
}

run().catch(console.dir);

Replace 'your_mongodb_connection_string' with your actual MongoDB URI.

Always use async/await to handle the connection properly.

Examples

Connects to a local MongoDB server running on default port 27017.

Node.js

import { MongoClient } from 'mongodb';

const uri = 'mongodb://localhost:27017';
const client = new MongoClient(uri);

async function run() {
  await client.connect();
  console.log('Connected to local MongoDB');
  await client.close();
}

run();

Connects to a MongoDB Atlas cloud database using a connection string with username and password.

Node.js

import { MongoClient } from 'mongodb';

const uri = 'mongodb+srv://user:[e-mail]/mydb?retryWrites=true&w=majority';
const client = new MongoClient(uri);

async function run() {
  await client.connect();
  console.log('Connected to MongoDB Atlas');
  await client.close();
}

run();

Sample Program

This program connects to a local MongoDB, inserts one document into 'testcollection' in 'testdb', then closes the connection.

Node.js

import { MongoClient } from 'mongodb';

const uri = 'mongodb://localhost:27017';
const client = new MongoClient(uri);

async function run() {
  try {
    await client.connect();
    console.log('Connected to MongoDB');
    const database = client.db('testdb');
    const collection = database.collection('testcollection');
    const doc = { name: 'Alice', age: 25 };
    const result = await collection.insertOne(doc);
    console.log('Inserted document id:', result.insertedId);
  } finally {
    await client.close();
  }
}

run().catch(console.dir);

Important Notes

Make sure MongoDB server is running before connecting.

Use try/finally to close the connection even if errors happen.

The insertedId is a unique ID MongoDB creates for each document.

Summary

Use MongoClient from 'mongodb' package to connect.

Always connect and close the client properly with async/await.

Replace the URI with your MongoDB server address.