Fight the Rot - Refactor stinky JavaScript

Is you node.js application hard to maintain? Is your buglist growing while the list of deployable features shrinks? Is bad code slowing you down? Then the rot has taken over and you are probably afraid of touching your code.

I will show you how to start refactoring, when there are no tests around, no documentation exists, and architecture is hard to understand. Covering strategy, unit tests, documentation, measuring progress, tools, best practices and things to avoid.

Transcript

1. Fight the Rot Refactor stinky JavaScript @damienklinnert Donnerstag, 18. Juli 13
2. a typical day? • Mr. Wheatley, owner of Copy+Paste Inc., asks for a (simple) change in his web store • backstage passes should rise by 3 points in quality, if there are less than 6 days to event Donnerstag, 18. Juli 13
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4. WAAAAAT??? Donnerstag, 18. Juli 13
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6. the hacky way ™ Donnerstag, 18. Juli 13
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9. done!(?) git add * && git commit && git push Donnerstag, 18. Juli 13
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11. Refactoring Donnerstag, 18. Juli 13
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19. step by step tut Donnerstag, 18. Juli 13
20. done!(?) git add * && git commit && git push Donnerstag, 18. Juli 13
21. refactoring is disciplined technique for restructuring an existing body of code, altering its internal structure without changing its external behavior Donnerstag, 18. Juli 13
22. refactoring • break dependencies • bring system under tests • refactor • add feature • measure code quality Donnerstag, 18. Juli 13
23. break dependencies • factories, abstract factories • dependency injection knit.js • pass as parameter Donnerstag, 18. Juli 13
24. add tests • mocha, karma.js • instrument with istanbul, js-coverage • test current behavior, not expected Donnerstag, 18. Juli 13
25. refactor • few good tools around for js • pair programming Donnerstag, 18. Juli 13
26. add feature • design patterns Donnerstag, 18. Juli 13
27. measure code quality • plato.js • jscomplexity • node-madge Donnerstag, 18. Juli 13
28. clean code • everything is pretty much what you expect • documented • as if by one and the same author • following your style guide Donnerstag, 18. Juli 13
29. bad code • detect with jsmeter • or jshint complexity settings • not linted • not tested • complex Donnerstag, 18. Juli 13
30. thank you! follow me on twitter @damienklinnert Donnerstag, 18. Juli 13