How to Manage Environment Variables using ES6 in Node.js with dotenv

In modern web development, handling sensitive data like API keys, database credentials, or secret tokens securely is crucial. A popular method for managing such environment variables is by using .env files. In this article, we will explore how to use the dotenv package in a Node.js environment with ES6 Modules (ESM).

What is dotenv?

The dotenv package allows you to load environment variables from a .env file into process.env in Node.js. This approach helps keep sensitive information out of your codebase and version control, making it safer and easier to manage configurations across different environments (development, staging, production, etc.).

Setting Up a Node.js Project with ES6 Modules

Before we start using the dotenv package, we need to set up a Node.js project that uses ES6 Modules (import/export).

• Initialize a Node.js Project

• Open your terminal and run the following command to create a new project:

mkdir my-dotenv-project cd my-dotenv-project npm init -y

• Enable ES6 Modules

• In your package.json file, add the following to enable ES6 module support:

{ "type": "module" }

• Install dotenv Package
• Now, install the dotenv package via npm:

npm install dotenv

Creating and Configuring the .env File

The .env file stores your environment variables in a key-value format. Here’s how to create and configure it:

• Create a .env File
• In the root of your project, create a file named .env

• Add Environment Variables
• Add key-value pairs representing your environment variables. For example:

API_KEY=your-api-key-here DB_PASSWORD=your-database-password-here SECRET_TOKEN=your-secret-token-here

• Important: Ensure that .env is added to your .gitignore file to prevent it from being committed to version control.

Using dotenv with ES6 Modules

To load the environment variables defined in the .env file into your Node.js project using ES6 Modules, follow these steps:

• Create Your JavaScript File
• Create an index.js file ( or any JavaScript file where you want to use the environment variables).

• Import dotenv and Load Variables
• In your index.js, use the ES6 import syntax to import the dotenv package and load the environment variables In this code:

import dotenv from 'dotenv'; 
  // Load environment variables from .env file 
dotenv.config();
 // Access environment variables using  
const apiKey = process.env.API_KEY; process.env  
const dbPassword = process.env.DB_PASSWORD; 
const secretToken = process.env.SECRET_TOKEN; 
// Log the variables (for testing purposes) 
console.log('API Key:', apiKey);
console.log('Database Password:', dbPassword);
console.log('Secret Token:', secretToken); 

• dotenv.config() loads the environment variables from the .env file into process.env.

• You can then access each environment variable using process.env.VARIABLE_NAME.

Run Your Application
To test if it works, run the following command in your terminal: node index.js This should output the values from your .env file (if you’ve set them correctly).

Best Practices for Using dotenv

• Keep .env File Secret
• Always ensure that your .env file is not committed to version control (e.g., Git). To do this, add .env to your .gitignore file: .env

• Use Default Values with dotenv
• It’s a good practice to set default values for critical environment variables to ensure your application doesn’t break if a variable is missing. You can achieve this like so:

const apiKey = process.env.API_KEY || 'default-api-key'; const dbPassword = process.env.DB_PASSWORD || 'default-db-password';

• Use Descriptive Names
• Name your environment variables descriptively to make them easy to understand for other developers who may work with your codebase.

Use Different .env Files for Different Environments

• You can create multiple .env files for different environments (e.g., .env.development, .env.production). Use a tool like cross-env or configure your build system to load the correct .env file depending on the environment.

Example: Building a Simple App Using dotenv

• Let’s create a simple app that connects to a database (we will just simulate this with a console log) using the environment variables.

• Update .env
• Add the following to your .env file:

DB_HOST=localhost DB_USER=root DB_PASSWORD=secretpassword

• Create index.js

import dotenv from 'dotenv'; dotenv.config(); const dbHost = process.env.DB_HOST; const dbUser = process.env.DB_USER; const dbPassword = process.env.DB_PASSWORD; // Simulate a database connection console.log(`Connecting to database at ${dbHost}...`); console.log(`Using user: ${dbUser}`); console.log(`Password: ${dbPassword}`);

• Run the App
• Run the application with: node index.js The output should look like: Connecting to database at localhost... Using user: root Password: secretpassword

Using dotenv with ES6 modules in Node.js is a great way to manage sensitive data and environment-specific configurations. By keeping your credentials and configuration separate from your code, you ensure better security, flexibility, and maintainability in your applications. With the steps outlined above, you should be able to easily set up dotenv in your Node.js project and start using environment variables for various purposes.

Happy coding!