Jassif Team Institution

// Access a single environment variable
const nodeEnv = process.env.NODE_ENV || 'development';
console.log(`Running in ${nodeEnv} mode`);

// Access multiple variables with destructuring
const { PORT = 3000, HOST = 'localhost' } = process.env;
console.log(`Server running at http://${HOST}:${PORT}`);

// Check if running in production
if (process.env.NODE_ENV === 'production') {
  console.log('Production optimizations enabled');
  // Enable production features
}

set PORT=3000
set NODE_ENV=development
set DB_HOST=localhost
node app.js

$env:PORT=3000
$env:NODE_ENV="development"
node app.js

PORT=3000 NODE_ENV=development DB_HOST=localhost node app.js

export PORT=3000
export NODE_ENV=development
node app.js

npm install dotenv

# .env
PORT=3000
NODE_ENV=development
DB_HOST=localhost
DB_USER=admin
DB_PASS=your_secure_password
API_KEY=your_api_key_here

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

const port = process.env.PORT || 3000;
const dbConfig = {
  host: process.env.DB_HOST,
  user: process.env.DB_USER,
  password: process.env.DB_PASS
};

console.log(`Server running on port ${port}`);

heroku config:set NODE_ENV=production DATABASE_URL=your_database_url

docker run -e NODE_ENV=production -e PORT=3000 your-image

# /etc/systemd/system/your-app.service
[Service]
Environment="NODE_ENV=production"
Environment="PORT=3000"

.env ফাইল

# .env file
API_KEY=abcdef12345

আপনার অ্যাপ্লিকেশনে ভেরিয়েবল লোড করুন

require('dotenv').config();
console.log(process.env.API_KEY);

npm install dotenv