Environment Variables in Node.js

Overview

Environment variables are a way to store configuration settings and sensitive information separately from your code. This helps keep your application secure and flexible across different environments (development, testing, production).

Setting Up Environment Variables

In a Node.js application, you can create a file named .env in the root directory to define your environment variables:

# .env
DATABASE_URL=mongodb://localhost:27017/mydatabase
SECRET_KEY=mysecretkey

Using dotenv Package

To load environment variables from the .env file, you need to install the dotenv package:

npm install dotenv

Then, require and configure it at the beginning of your application:

// server.js or app.js
require('dotenv').config(); // Load environment variables

const dbUrl = process.env.DATABASE_URL;
console.log('Database URL:', dbUrl);

Accessing Environment Variables

You can access environment variables in your application using process.env.VARIABLE_NAME. Here's an example:

// Using environment variables
const express = require('express');
const app = express();
require('dotenv').config();

app.get('/', (req, res) => {
  res.send('Secret Key: ' + process.env.SECRET_KEY);
});

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

Best Practices

Here are some best practices for using environment variables:

• Never commit your .env file to version control (add it to .gitignore).
• Use descriptive variable names to make it clear what each variable does.
• Consider using a service like dotenv-safe for additional security.