Node.js
Setting Environment Variables in package.json
Learn how to streamline your development workflow by securely setting and managing environment variables directly within your package.json file.
Learn how to streamline your development workflow by securely setting and managing environment variables directly within your package.json file.
This article explains how to effectively use environment variables in your npm scripts within a package.json file, although you can't directly set them there. It covers the concept of environment variables, methods to define them, how to access them in package.json scripts, ensuring cross-platform compatibility, and accessing them within your application code. Additionally, it highlights important security considerations and best practices for clarity and consistency.
While you can't directly set environment variables within the package.json file, you can use them effectively in your npm scripts. Here's a breakdown:
1. Understanding Environment Variables
Environment variables are key-value pairs that exist outside your code, providing configuration information to your application. They are useful for:
2. Defining Environment Variables
You have several options for defining environment variables:
Directly in the terminal: This is temporary and only lasts for the current session.
API_KEY=your_api_key node app.jsUsing a .env file: This is a common practice for managing environment variables. You can use the dotenv package to load variables from this file.
# .env file
API_KEY=your_api_key
NODE_ENV=development// app.js
require('dotenv').config();
console.log(process.env.API_KEY); // Accessing the environment variableSystem-wide environment variables: These are persistent but may not be suitable for all use cases.
3. Accessing Environment Variables in package.json Scripts
You can access environment variables within your package.json scripts using the process.env object in Node.js.
{
"name": "my-app",
"scripts": {
"start": "NODE_ENV=production node app.js",
"dev": "NODE_ENV=development nodemon app.js",
"build": "webpack --mode=production"
}
}In this example:
NODE_ENV=production sets the NODE_ENV environment variable to "production" before running node app.js.NODE_ENV=development sets the NODE_ENV environment variable to "development" before running nodemon app.js.build script doesn't explicitly set an environment variable but relies on the default behavior of tools like webpack.4. Using cross-env for Cross-Platform Compatibility
The way environment variables are set directly in scripts can differ between operating systems. To ensure cross-platform compatibility, use the cross-env package:
{
"scripts": {
"start": "cross-env NODE_ENV=production node app.js"
}
}5. Accessing Environment Variables in Your Application
Once you've set environment variables, you can access them in your JavaScript code using process.env:
// app.js
console.log(`Running in ${process.env.NODE_ENV} mode`);
if (process.env.NODE_ENV === 'production') {
// Production-specific logic
} else {
// Development-specific logic
}Important Considerations:
.env file (which should be added to your .gitignore).This Node.js code demonstrates environment-based configuration and API key management. It uses environment variables to determine the running environment and load sensitive data like API keys. The code includes environment-specific logic and handles cases where the API key is missing. The package.json file defines scripts for development and production workflows, utilizing tools like cross-env and nodemon. A .env file, ignored by version control, stores the API key securely. This setup ensures flexibility and security across different environments.
// app.js
// Accessing environment variables
const environment = process.env.NODE_ENV || 'development'; // Default to 'development'
const port = process.env.PORT || 3000;
console.log(`Running in ${environment} mode on port ${port}`);
// Environment-specific logic
if (environment === 'production') {
console.log('Production-specific setup...');
} else {
console.log('Development-specific setup...');
}
// Example API key usage (replace with your actual API key)
const apiKey = process.env.API_KEY;
if (apiKey) {
console.log('API key is available.');
// Make API calls using the apiKey
} else {
console.warn('API key not found. Some functionality may be limited.');
}
// ... rest of your application codepackage.json:
{
"name": "my-app",
"scripts": {
"start": "node app.js",
"dev": "cross-env NODE_ENV=development nodemon app.js",
"build": "cross-env NODE_ENV=production webpack --mode=production"
},
"dependencies": {
"cross-env": "^7.0.3",
"dotenv": "^16.0.3",
"nodemon": "^2.0.20",
"webpack": "^5.75.0"
}
}.env (should be added to .gitignore):
API_KEY=your_actual_api_key
Explanation:
NODE_ENV for environment differentiation and PORT for server configuration.cross-env for cross-platform compatibility.To run the application:
npm install
npm run dev
npm run build
node dist/main.js (or the appropriate command for your build output)This example demonstrates how to effectively use environment variables in a Node.js application, ensuring security and flexibility across different environments. Remember to replace placeholder values with your actual configuration.
Best Practices:
.env File: Always store sensitive data like API keys and database credentials in a .env file. This file should be added to your .gitignore to prevent it from being committed to version control.Advanced Usage:
dotenv-expand to dynamically set environment variables based on user input or other factors.Troubleshooting:
.env file, system-wide).cross-env to ensure that your scripts work consistently across different operating systems.console.log(process.env) to inspect the available environment variables and their values during development.Alternatives to Environment Variables:
Security Considerations:
.env file to store sensitive data securely.By following these best practices and understanding the nuances of environment variables, you can effectively manage configuration settings, enhance security, and streamline your development workflow.
This article explains how to leverage environment variables within your package.json scripts for enhanced configuration and flexibility.
Key Takeaways:
.env file (common practice), or system-wide.process.env within your package.json scripts to access defined environment variables.cross-env package to ensure consistent environment variable setting across different operating systems.process.env.Best Practices:
.env files and add them to your .gitignore.In conclusion, while you can't directly embed environment variables within the package.json file itself, you can seamlessly integrate them into your npm scripts. This approach brings numerous benefits, including enhanced security for sensitive data, streamlined environment management, and improved code clarity. By understanding the methods for defining, accessing, and utilizing environment variables effectively, developers can significantly enhance their project configuration and overall development workflow. Remember to prioritize security by never committing sensitive information directly to version control and instead leverage .env files for secure storage. By adhering to best practices and utilizing the techniques outlined in this article, you can harness the power of environment variables to create more robust, adaptable, and secure Node.js applications.
How to use .env variables in package.json | by Ray Knight | Medium | A simple cross platform way to utilize secrets in build scripts without writing shell scripts
node.js - How to use environment variables in package.json - Stack ... | Jan 7, 2016 ... In case you use .env file, let's use grep or eval to get a value environment variable from the .env file. Updated start2 as @Paul suggested:
How to use environment variables in NPM scripts safely ... - SwC | The term NODE_ENV might be substituted with something else, but the essence of the problem is that some code is trying to set an environment variable in a ... javascript - Setting process.env var in package.json - Stack Overflow | Mar 6, 2017 ... You cannot just set environment variables in package.json. You can set them in your script sections using:
How to set environment variables from within package json ... | How to set some environment variables from within package.json to be used with npm start like commands? ... the app with just one command, npm start.