What is the Twelve-Factor App methodology as it applies to Node.js?

The Twelve-Factor App is a methodology for building scalable, maintainable, cloud-native applications. Applied to Node.js: (1) Codebase: one codebase in version control; (2) Dependencies: explicitly declared in package.json — never rely on global packages; (3) Config: store config in environment variables (process.env) — not hardcoded; (4) Backing services: treat databases, queues as attached resources via URLs in config; (5) Build, release, run: separate stages — npm run build, tag release, node dist/app.js; (6) Processes: execute as stateless processes — no sticky sessions, no local file storage; (7) Port binding: self-contained HTTP service — app.listen(process.env.PORT); (8) Concurrency: scale via process model — cluster/PM2; (9) Disposability: fast startup, graceful shutdown on SIGTERM; (10) Dev/prod parity: minimize differences between environments — use Docker; (11) Logs: treat logs as event streams — write to stdout, let infrastructure route them; (12) Admin processes: run one-off admin tasks (migrations, scripts) in the same environment as the app.