Node.js Flags & Options
JavaScript runtime built on V8.All Node.js pages
- node --env-file=.env: load environment variables without dotenvnode --env-file=.env app.js loads variables from a .env file into process.env, no dotenv package needed (Node 20.6+). Precedence, multiple files, loadEnvFile().
- node --import and -r (--require): preload a module before the app startsnode -r ./setup.cjs and node --import ./setup.mjs load a module before the app starts. Order, NODE_OPTIONS, dotenv, loaders, missing preload errors, pitfalls.
- node --inspect: open the debugger for Chrome DevTools and VS Codenode --inspect starts the V8 inspector on 127.0.0.1:9229 for Chrome DevTools and VS Code. --inspect-brk, custom ports, address in use errors and security risks.
- node --watch: restart the app when a file changes (no nodemon)node --watch app.js restarts the script when it or an imported module changes, without nodemon (Node 18.11+). --watch-path, preserved output, limits, pitfalls.