How do I debug Node.js applications?

Question

How do I debug a Node.js server application?

Right now I\'m mostly using alert debugging with print statements like this:

sys.puts(sys.inspe         


        

Answer 1

Debugging

• Joyent's Guide
• Debugger
• Node Inspector
• Visual Studio Code
• Cloud9
• Brackets

Profiling

1. node --prof ./app.js
2. node --prof-process ./the-generated-log-file

Heapdumps

• node-heapdump with Chrome Developer Tools

Flamegraphs

• 0x
• jam3/devtool then Chrome Developer Tools Flame Charts
• Dtrace and StackVis — Only supported on SmartOS
• clinicjs

Tracing

• Interactive Stack Traces with TraceGL

Logging

Libraries that output debugging information

• Caterpillar
• Tracer
• scribbles

Libraries that enhance stack trace information

• Longjohn

Benchmarking

• Apache Bench: ab -n 100000 -c 1 http://127.0.0.1:9778/
• wrk

Other

• Trace
• Vantage
• Bugger
• Google Tracing Framework
• Paul Irish's Guide

Legacy

These use to work but are no longer maintained or no longer applicable to modern node versions.

• https://github.com/bnoordhuis/node-profiler - replaced by built-in debugging
• https://github.com/c4milo/node-webkit-agent - replaced by node inspector
• https://nodetime.com/ - defunct