How do I debug Node.js applications?

javascript

debugging

nodejs

performance

byAlex Kataev·Aug 19, 2024

To debug Node.js, use node --inspect to activate Chrome's DevTools or VS Code breakpoints. Inside your app, plant debugger; where you want the execution to pause. Pull up Chrome and navigate to chrome://inspect to open the DevTools, or kick-off your Node.js code within VS Code, setting breakpoints visually. Hit F5 in VS Code to initiate debugging with awesome features like code inspection and step-through.

// So here is the game-plan...
debugger; // Drop your breakpoint here.

// Switch on Chrome DevTools for debug mode.
// Just like turning on night-vision goggles!
node --inspect your_file.js

// Within the VS Code matrix:
// Click adjacent to the line number to position a breakpoint.
// Don't worry, it doesn't hurt. 
// Press F5 and become The One.

Dialling up the debug game

To crank up your debugging wizardry, employ these potent tools and cyberspace gadgets:

Trial node-inspector for a feature-rich debugging interface: npm install -g node-inspector and then node-debug app.js did the job.
For deep-diving into performance data, nothing beats 0x, Clinicjs, and TraceGL.
Spotting memory leaks is no more a nuisance, deceive them with heap snapshots a.k.a node-heapdump.
Reveal the CPU's secrets with node --prof and interpret that treasure-map by node --prof-process.
Unravel the log's mysteries with custom logging using Caterpillar or Tracer. It's like finding secret messages in an old bottle.

The art of error prophecy

Boost debugging precision with these error-clarifying and time-twisting live-editing tools:

Longjohn stretches stack traces, unmasking the true faces of asynchronous code errors.
Vantage.js tosses in a terminal-based real-time interface, the best VIP view for live debugging.
Bugger masterfully paints Chrome’s debugging picture on Node.js in a user-friendly browser canvas.

Armament for the debug detective

Flex your Node.js debugging muscles with these sterling resources and tips:

For 24x7 performance patrols, check out RisingStack's Trace.
Trust and deploy the Google Tracing Framework for excavating JavaScript performance mysteries.
Tune into the wisdom of Paul Irish's and his bag full of Chrome profiling and debugging automation tricks.
Apply benchmarking tools like Apache Bench or wrk to task your app. It's gym-time for your code!
Eclipse users, get your supernova ready with guide from Node.js GitHub wiki for an Eclipse setup.
When all fails resort to the good ol' debugging with node debug script.js. It's like the grandpa's magic trick.

The knowledge pool for continuous learning

Keep your debug skills razor-sharp with these resources:

Visit Node.js’s official debugger documentation to brush up on the basics.
To teeter on the edge of cutting-edge techniques, explore the Node.js GitHub wiki.
Stay ahead of the curve by diving into developer communities. Remember, sharing is caring!

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