How To Use dotenv (.env) In Node.js?

When working on a Node.js project, you often need to manage sensitive data like API keys, database credentials, and other environment-specific configurations. Instead of hardcoding these values directly into your code, a better practice is to store them in a .env file. This allows you to keep your configuration separate from your codebase and ensures that sensitive information is not exposed in your source code, especially when pushing it to version control systems like Git.

What Is dotenv?

dotenv is a zero-dependency Node.js module that loads environment variables from a .env file into process.env. The .env file should be placed in the root directory of your project. This file contains key-value pairs of environment variables that can be used within your application.

Steps to use dotenv

1. Open up any terminal inside your project work space and install dotenv.

    npm install dotenv
   

2. Create a .env file in the root directory of your project.

    my-node-app/
    ├── node_modules/
    ├── other_folder/
    ├── .env
    ├── index.js
    ├── package.json
    └── package-lock.json
   

3. Add your environment variable in .env file as key value pairs .

    DB_URL=mongodb+srv://username:password@cluster0.pahbl.mongodb.net
    DB_NAME=mydb
    PORT=5000
   

4. Import and configure the dotenv package at the top of your main JavaScript file (e.g., index.js).

    const dotenv = require('dotenv')
    dotenv.config()
    //or
    require('dotenv').config();
   

5. Load the environment variable from .env file.

    const dbUrl = process.env.DB_URL;
    const dbName = process.env.DB_NAME;
   

   Default Values: You can also set default values directly in your code in case an environment variable is not defined in the .env file. For example, you can use the following syntax for the PORT variable:

    const port = process.env.PORT || 3000;
   

Important Notes

Never Commit Your .env File to Version Control: Since the .env file contains sensitive information (like API keys and database passwords), you should never commit it to version control (Git). To prevent this, add the .env file to your .gitignore:

# .gitignore
.env

Conclusion

Using the dotenv package in Node.js is a simple and effective way to manage environment variables. It helps keep sensitive data like API keys and database credentials safe, and it makes your code more maintainable by separating configuration from code logic.

By following the steps outlined in this article, you can easily manage different configurations for different environments and ensure that your application behaves consistently across different stages of development.

Happy coding!