Node.js Patterns#

Production-grade Node.js backend patterns.

Async Patterns#

Prefer Async/Await#

// Good
async function getUser(id) {
  const user = await db.findUser(id);
  return user;
}

// Avoid raw callbacks or.then() chains

Parallel Execution#

// 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#

process.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#

app.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)

Node.js Patterns

Node.js Patterns#

Async Patterns#

Prefer Async/Await#

Parallel Execution#

Error Handling#

Global Handler#

Express Error Middleware#

Module Design#

Production Hardening#

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