Learn .env in Express.js for Beginners (Effortless Setup)

In this guide, you'll learn how to securely manage your MongoDB connection string using the .env file in an Express.js backend project. Let's dive in! 🚀

Step 1: Install dotenv 📦

First, install the dotenv package to read environment variables from your .env file:

npm install dotenv

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Step 2: Create a .env File 🛠️

Create a .env file in the root of your project and store your MongoDB URI in it. For example:

MONGO_URI=mongodb+srv://<username>:<password>@cluster0.mongodb.net/<database>?retryWrites=true&w=majority

Replace <username>, <password>, and <database> with your actual database credentials.

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Step 3: Load Environment Variables 🌐

In your main project file (e.g., index.js or app.js), import and configure dotenv at the very top:

import dotenv from 'dotenv';
dotenv.config();

This ensures that all variables in your .env file are loaded into process.env.

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Step 4: Use the Environment Variable 🛡️

Now, use the environment variable MONGO_URI in your MongoDB connection:

mongoose.connect(process.env.MONGO_URI, {
    useNewUrlParser: true,
    useUnifiedTopology: true,
})
.then(() => console.log('Connected to MongoDB'))
.catch(err => console.error('Error connecting to MongoDB:', err));

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Step 5: Add .env to .gitignore 🚫

To prevent exposing sensitive data (like your MongoDB URI) in version control, add .env to your .gitignore file:

.env

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Security Tip 🔒

Never hardcode sensitive information like usernames, passwords, or database URLs directly in your code. Always use environment variables for a secure and clean setup.

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Full Example: index.js 📝

Here’s a complete example of an Express.js app connected to MongoDB using the .env file:

import express from 'express';
import mongoose from 'mongoose';
import cors from 'cors';
import UserRoute from './routes/UserRoute.js';
import dotenv from 'dotenv';

dotenv.config();

const app = express();

mongoose.connect(process.env.MONGO_URI, {
    useNewUrlParser: true,
    useUnifiedTopology: true,
});

const db = mongoose.connection;
db.on('error', (error) => console.log(error));
db.once('open', () => console.log('Database Connected'));

app.use(cors());
app.use(express.json());

// Routes
app.use(UserRoute);

app.listen(5080, () => console.log('Server is running'));

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Ready to Go! 🎉

If you’ve followed these steps correctly, your project should now be securely connected to MongoDB using environment variables. Happy coding! 😊

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