Avoiding Event-Loop Blocking
Node.js performance depends heavily on keeping the event loop responsive. Expensive synchronous operations, huge JSON parsing or serialization, inefficient regular expressions, and CPU-heavy algorithms can delay unrelated requests.
Performance optimization should begin with measurement rather than assumptions.
Avoid CPU-Heavy Work in Request Handlers
app.get('/report', async (req, res) => {
const report = await generateReportInWorker(req.query.id);
res.json(report);
});💡 CPU-intensive report generation can be moved to a worker or background job so the HTTP event loop remains responsive.
Key Takeaways
- Keep request handlers lightweight when possible.
- Move expensive CPU work to workers or background processes.
- Measure event-loop latency to detect blocking workloads.
Knowledge Check
What is a common cause of poor Node.js concurrency?