Node.js Debugging

What is Debugging in Node.js?

Node has a built-in inspector that connects to Chrome DevTools or VS Code, giving breakpoints, step-through execution and variable inspection — far more effective than scattering console.log calls.

Debugging example

node --inspect src/index.js         # attach a debugger
node --inspect-brk src/index.js     # pause on the first line
# then open chrome://inspect in Chrome

Key points to remember

• VS Code can launch and attach with a one-click debug configuration.
• console.table and console.dir with { depth: null } beat plain logging for objects.
• The NODE_DEBUG environment variable enables Node’s internal logging.
• node --test --watch reruns tests on save.

Common mistakes with Debugging

• Exposing the inspector port on a public server — it allows arbitrary code execution.
• Leaving console.log calls in production code instead of using a real logger.