How to Connect to MongoDB Database using Node.js and Express.js

Connecting to a database is an essential step in creating a web application. MongoDB is a popular NoSQL database that is commonly used with Node.js and Express.js.

Here are the steps to connect to a MongoDB database using Node.js and Express.js:

1. Install MongoDB: If you haven’t already installed MongoDB, you can download it from the official website and follow the installation instructions for your operating system.
2. Install Node.js and Express.js: Make sure you have Node.js and Express.js installed on your machine. You can do this by running the following commands in your terminal:

   npm install node
   npm install express

3. Install the MongoDB driver for Node.js: You can install the MongoDB driver for Node.js using the npm package manager by running the following command in your terminal:

   npm install mongodb

4. Create a new Node.js and Express.js project: Create a new directory for your project and run the following commands in your terminal to create a new Node.js and Express.js project:

   mkdir my-mongodb-project
   cd my-mongodb-project
   npm init -y
   npm install express mongodb

5. Connect to the MongoDB database: In your Node.js and Express.js project, you can connect to the MongoDB database by using the following code:

const express = require('express');
const mongodb = require('mongodb');
const app = express();

// Replace the connection string with your MongoDB connection string
const connectionString = 'YOUR_MONGODB_CONNECTION_STRING';

app.get('/', async (req, res) => {
  const client = await mongodb.MongoClient.connect(connectionString, {
    useUnifiedTopology: true
  });
  // Perform operations on the database
  const db = client.db('my-database');
  const collection = db.collection('my-collection');
  const data = await collection.find({}).toArray();
  res.json(data);
  client.close();
});

app.listen(3000, () => console.log('Server running on port 3000'));

Replace YOUR_MONGODB_CONNECTION_STRING with your actual MongoDB connection string. You can obtain this connection string from your MongoDB Atlas dashboard or from your local MongoDB installation.

With these steps, you should now be able to connect to your MongoDB database using Node.js and Express.js. Now, you can perform CRUD operations and create a powerful web application with MongoDB as your database.