Environment Variables and process

Node.js provides a global process object.

It gives information and control over the running Node process.

process.env

Environment variables store configuration outside the code.

Example:

const port = process.env.PORT || 3000
const dbUrl = process.env.DATABASE_URL

Common values:

• PORT,
• DATABASE_URL,
• JWT_SECRET,
• NODE_ENV,
• API keys.

Why env vars matter

Do not hardcode secrets:

const jwtSecret = 'my-secret'

Better:

const jwtSecret = process.env.JWT_SECRET

Different environments can use different values:

• local,
• staging,
• production.

process.argv

process.argv contains command line arguments.

console.log(process.argv)

Useful for CLI scripts.

process.exit

Exit with success:

process.exit(0)

Exit with failure:

process.exit(1)

Interview answer

The process object provides information about the running Node.js process. process.env is used for configuration and secrets through environment variables. process.argv reads command-line arguments, and exit codes communicate success or failure to the operating system.