Node.js debugging
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The document provides an overview of debugging techniques for Node.js applications, emphasizing the use of various tools like the built-in debugger, Eclipse IDE, Chrome DevTools, and WebStorm for effective debugging. Key commands and features such as setting breakpoints, watching expressions, and execution control are highlighted. It also mentions the compatibility issues with plugins and the advantages of certain IDEs for Node.js debugging.
Node.js debugging
- 1. Pittsburgh http://www.meetup.com/Pittsburgh-Node-js/ Last Wednesday of every month 7-9pm Right here at LeBrew House!
- 2. Nicholas McClay Designer and Developer @nickmcclay
- 4. In the beginning there was ‘debugger’ http://nodejs.org/api/debugger.html To debug in console: node debug test.js note: 'debug' not '--debug', this is a different command we'll see later This hook to V8's debugger is what all Node debug tools bind to.
- 5. Debug command highlights • Stepping – cont, next, step, out - What you think they do • Breakpoints – setBreakpoint()/sb() - Set breakpoint on current line or at statement – clearBreakpoint/clearBreakpoint()/cb(...) - clear breakpoint (duh)
- 6. Debug command highlights • Info – backtrace/bt - Print backtrace of current execution frame – watch(expr) - Add expression to watch list – unwatch(expr) - Remove expression from watch list – watchers - List all watchers and their values – repl - Open debugger's repl for evaluation in debugging script's context • Execution control – run - Run script (automatically runs on debugger's start) – restart - Restart script – kill - Kill script
- 7. Can’t we use something a little less… Arcane? Unusual? Ugly? 1990?
- 8. Eclipse IDE Eclipse Node Debugger Walk Through: https://github.com/joyent/node/wiki/Using- Eclipse-as-Node-Applications-Debugger Chrome Dev Tools + V8 Debugger: http://code.google.com/p/chromedevtools/ Warning, plug-in compatibility can be a nightmare! Aptana or other highly customized Eclipse based IDE's may not work.
- 9. Eclipse advanced debugging To debug with real source instead of 'VirtualProject' files http://code.google.com/p/chromedevt ools/wiki/FeatureDebugOnRealFiles Screen capture of setup http://www.youtube.com/watch?v=GV xFFw7lkYg
- 10. Webstorm IDE Happy Node.js debugging right out of the box! Coffeescript debugging coming in version 4.0!
- 12. node-inspector Webkit Inspector debugging https://github.com/dannycoates/node-inspector front-end JavaScript debugger reused for back-end JavaScript, what a great idea! 1.) npm install –g node-inspector 2.) node --debug-brk test.js 3.) node-inspector 4.) Open browser to http://localhost:8080/debug?port=5858
- 13. Final Thoughts • --debug vs --debug-brk • Remote Debugging • Long stack traces http://stackoverflow.com/questions/7697038/more- than-10-lines-in-a-node-js-stack-error