Refactoring with examples

The Why, Whens, and Hows refactoring. Inspired by Refactoring: Ruby Edition.

Transcript

1. Refactoring Adam Jonas
2. Other places I live... adamjonas.com @adamcjonas adam.jonas@flatironschool.com
3. How I learned Spanish as an adult - Vocabulary - Patterns - Fluency
4. How I've learned to code - Vocab - Exercises - Patterns - Projects
5. Refactoring Patterns - If you don't know the patterns, you are less likely to capture their wisdom. - We learn through heuristics.
6. Learning Great Habits “I'm not a great programmer; I'm just a good programmer with great habits.” - Kent Beck
7. More Kent Beck Wisdom... Make it work Make it right Make it fast Refactoring is about making it right
8. Etymology of Refactoring From factoring: x2 + x - 12 = 0 => (x + 4)(x - 3) = 0
9. Refactoring is... A change made to the internal structure of software to make it easier to understand and cheaper to modify without changing its observable behavior. [p. 53]
10. Refactoring and Baby Pandas - Who doesn't like rainbows? baby pandas? parfait? - But why is refactoring important?
11. Advantages 1. Remove Duplication 2. Simplify Code 3. Increases readability and clarify your code's intent.
12. Why should I do it? - Code I wrote yesterday isn't as good as today - Know more about the system and I can apply that knowledge. - Make it easier to add new code - Help the next person understand -
13. "Programs must be written for people to read, and only incidentally for machines to execute." - Abelson & Sussman, Structure and Interpretation of Computer Programs "Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” - Refactoring [p.11] Why change code that works?
14. Got to have tests to let you know when it's broken. TDD: Red, Green, Refactor Know when you broke your code
15. Code Smells - Duplicated Code - Long method - Large class - Long parameter list - Local variable assigned more than once, but not a loop or collection
16. - Replace Loop With a Collection - Extraction method - Dynamic Method Definition Refactoring Patterns
17. Each with a <<
18. Make each with << a collection
19. Each, <<, and Conditional
20. Each, <<, & Conditional using select
21. Combo of the last two
22. So...
23. Building an object with each
24. Inject
25. Extraction Pattern Turn a fragment into a method whose name explains the purpose of the method. In the wild:
26. Refactor
27. Refactor #2
28. Refactor Summary
29. You warmed up yet?
30. Practical Example => Making it work
31. Repo Parameters
32. Dynamic Method Definition
33. Issue Parms
34. Dynamic Method Definition Issue Parameters
35. Better or worse?
36. Questions?
37. Photos: - http://www.flickr.com/photos/cobalt/5637229371 - http://www.flickr.com/photos/sheeshoo/258734514 - http://www.flickr.com/photos/ruoxinyi/4596954281 - http://www.flickr.com/photos/rockerbotrhi/3858953947/ - http://www.flickr.com/photos/kenberg/6311136154/ - http://www.flickr.com/photos/sanchom/2963072255 - http://www.flickr.com/photos/broken_simulacra/118535492 - http://cdn.memegenerator.net/instances/400x/26336623.jpg Books: Refactoring: Ruby Edition By Fields, Harvie, Fowler with Beck, 2010 Structure and Interpretation of Computer Programs, By Abelson, Sussman, 1985 Catalog: - http://www.refactoring.com/catalog/index.html Sources