Node.js Patterns
Production-grade Node.js backend patterns.
Async Patterns
Prefer Async/Await
javascript// Good async function getUser(id) { const user = await db.findUser(id); return user; } // Avoid raw callbacks or.then() chains
Parallel Execution
javascript// Sequential (slow) const user = await fetchUser(id); const posts = await fetchPosts(id); // Parallel (fast) const [user, posts] = await Promise.all([ fetchUser(id), fetchPosts(id), ]);
Error Handling
Global Handler
javascriptprocess.on('uncaughtException', (err) => { console.error('Uncaught:', err); // Graceful shutdown server.close(() => process.exit(1)); }); process.on('unhandledRejection', (reason) => { console.error('Unhandled Rejection:', reason); });
Express Error Middleware
javascriptapp.use((err, req, res, next) => { const status = err.status || 500; res.status(status).json({ error: err.message, ...(process.env.NODE_ENV === 'development' && { stack: err.stack }), }); });
Module Design
- Single responsibility per module
- Export a class or factory function, not plain objects
- Use dependency injection for testability
- Prefer CommonJS (require) or ESM (import), consistent throughout
Production Hardening
- Cluster mode for multi-core
- Process manager (PM2) with auto-restart
- Health check endpoints
- Graceful shutdown (SIGTERM handler)
- Memory limit monitoring
- Structured logging (pino/winston)
