Securely Manage Environment Variables in Node.js Applications

require('dotenv').config(); // Load environment variables from .env file

// Accessing environment variables
const DB_HOST = process.env.DB_HOST || 'localhost';
const DB_USER = process.env.DB_USER || 'root';
const DB_PASSWORD = process.env.DB_PASSWORD; // No default for sensitive credentials
const API_KEY = process.env.API_KEY;
const NODE_ENV = process.env.NODE_ENV || 'development';

function connectToDatabase() {
    if (!DB_PASSWORD) {
        console.error('Error: DB_PASSWORD environment variable is not set.');
        // In a real application, you might throw an error or exit process
        return null;
    }
    console.log(`Connecting to database at ${DB_HOST} as ${DB_USER}...`);
    // Example database connection (pseudo-code)
    // return new DatabaseClient({
    //     host: DB_HOST,
    //     user: DB_USER,
    //     password: DB_PASSWORD
    // });
    console.log('Database connection details loaded securely.');
}

function makeApiRequest() {
    if (!API_KEY) {
        console.error('Error: API_KEY environment variable is not set.');
        return null;
    }
    console.log(`Making API request with key: ${API_KEY.substring(0, 5)}...`); // Log first 5 chars for debug
    // Example API call (pseudo-code)
    // return fetch(`https://api.example.com/data?key=${API_KEY}`);
    console.log('API request made with securely loaded key.');
}

console.log(`Application running in ${NODE_ENV} mode.`);

connectToDatabase();
makeApiRequest();

// Example of a .env file content:
// DB_HOST=your_db_host
// DB_USER=your_db_user
// DB_PASSWORD=your_db_secret_password
// API_KEY=your_api_secret_key_12345
// NODE_ENV=production