How to use a MongoDB database with Node.js

We can easily connect Node.js to MongoDB, a highly scalable and flexible NoSQL database, you can easily connect from Node.js using the mongodb package.

How to Connect Node.js to MongoDB

First, we install the mongodb package using npm:

npm install mongodb

This package will allow us to connect and perform operations with the MongoDB database from Node.js.

Creating the Connection File

Now we create a file to handle the connection to MongoDB (for example dbConnection.mjs). In this file, we will use the mongodb module to connect to the database.

import { MongoClient } from 'mongodb';

const uri = 'mongodb://localhost:27017'; // Connection URL to your database
const dbName = 'mydatabase'; // Name of your database

async function connect() {
  try {
    const client = new MongoClient(uri);
    await client.connect();
    const db = client.db(dbName);
    console.log('Connection to MongoDB established.');
    return db;
  } catch (error) {
    console.error('Error connecting to MongoDB:', error);
    throw error;
  }
}

export default connect;

Using the Connection in Your Application

Now that we have defined the connection function in dbConnection.mjs, we can import it and use it anywhere in our application to perform operations with the MongoDB database.

For example, in another file of your application app.mjs, we can use the connect function to get a connection to the database and perform operations like searching for documents, inserting new data, updating records, etc.

Let’s see it with an example:

import connect from './dbConnection.mjs';

async function fetchData() {
  const db = await connect();
  try {
    const collection = db.collection('my_collection');
    const result = await collection.find({}).toArray();
    console.log('Documents retrieved:', result);
  } catch (error) {
    console.error('Error fetching data:', error);
  } finally {
    db.close();
  }
}

fetchData();

In this example, we are retrieving all documents from the collection 'my_collection' and displaying the result in the console.

CRUD Operations

Once we have the connection file, we can use it to perform CRUD operations (Create, Read, Update, Delete) on our MongoDB database from Node.js.

Creating Data

const MongoClient = require('mongodb').MongoClient;

const url = 'mongodb://localhost:27017';
const dbName = 'my_database';

MongoClient.connect(url, { useNewUrlParser: true, useUnifiedTopology: true }, (err, client) => {
  if (err) throw err;

  const db = client.db(dbName);
  const collection = db.collection('my_collection');

  const newDocument = { name: 'Example', age: 30 };

  collection.insertOne(newDocument, (err, result) => {
    if (err) throw err;
    console.log('Document inserted successfully');
    client.close();
  });
});

Reading Data

const MongoClient = require('mongodb').MongoClient;

const url = 'mongodb://localhost:27017';
const dbName = 'my_database';

MongoClient.connect(url, { useNewUrlParser: true, useUnifiedTopology: true }, (err, client) => {
  if (err) throw err;

  const db = client.db(dbName);
  const collection = db.collection('my_collection');

  collection.find({}).toArray((err, docs) => {
    if (err) throw err;
    console.log('Documents found:');
    console.log(docs);
    client.close();
  });
});

Updating Data

const MongoClient = require('mongodb').MongoClient;

const url = 'mongodb://localhost:27017';
const dbName = 'my_database';

MongoClient.connect(url, { useNewUrlParser: true, useUnifiedTopology: true }, (err, client) => {
  if (err) throw err;

  const db = client.db(dbName);
  const collection = db.collection('my_collection');

  const filter = { name: 'Example' };
  const newValue = { $set: { age: 35 } };

  collection.updateOne(filter, newValue, (err, result) => {
    if (err) throw err;
    console.log('Document updated successfully');
    client.close();
  });
});

Deleting Data

const MongoClient = require('mongodb').MongoClient;

const url = 'mongodb://localhost:27017';
const dbName = 'my_database';

MongoClient.connect(url, { useNewUrlParser: true, useUnifiedTopology: true }, (err, client) => {
  if (err) throw err;

  const db = client.db(dbName);
  const collection = db.collection('my_collection');

  const filter = { name: 'Example' };

  collection.deleteOne(filter, (err, result) => {
    if (err) throw err;
    console.log('Document deleted successfully');
    client.close();
  });
});

Download the Code

All the code from this post is available for download on GitHub