Clean Code

A brief overview of how to write clean code,

Transcript

1. clean code from theory to practice by Luís Zamith
2. @zamith
4. Clean Code TAKING YOUR PROGRAMS TO THE LAUDRY
5. 1. Looks like you cared 2. Pretty much what you expected 3. Language looks as perfect fit for problem My definition
6. Design Patterns circular friction reduction device with central axis =
7. bad code class Report def initialize @title = 'Monthly Report' @text = [ 'Things are going', 'really, really well.' ] end def output_report ...HTML specific stuff... end end template method: reports
8. template method: reports better code class Report def initialize @title = 'Monthly Report' @text = ['Things are going', 'really, really well.'] end def output_report output_start output_head @text.each do |line| output_line(line) end output_end end def output_start; end def output_head output_line(@title) end def output_line(line) raise 'Called abstract method: output_line' end def output_end; end end
9. Design Principles THE THEORY BEHIND THE THEORY
10. S O L I D ingle responsibility pen closed iskov substitution nterface segragation ependency inversion Uncle Bob Martin
11. RECAP DESIGN PRINCIPLES DESIGN PATTERNS + = CLEAN CODE
12. Code Smells Sir, your issues have some code.
13. long method Smell number 1
14. Can’t tell what it does at a glance, it’s TOO LONG More than one level of nesting, probably TOO LONG TOO LONG More than one level of abstraction, may be Flog score greater than 15, may be TOO LONG REFACTOR
15. Extract Method: Split method into many auxiliary methods Solution #1
16. Replace temp with query: Move local variables into methods Solution #2
17. large class Smell number 2
18. Need to scroll to know what it does, it’s TOO BIG More private methods than public, it’s TOO BIG TOO BIG More than seven methods, probably Flog score greater than 50, may be TOO BIG REFACTOR
19. Extract class: If the class has multiple responsibilities Solution #1
20. Extract service object: If the class has many objects related to a single action Solution #2
21. strategy pattern: reports report = Report.new(HTMLFormatter.new) report.output_report report.formatter = PlainTextFormatter.new report.output_report
22. beware of the god class
23. feature envy Smell number 3 All your features are mine
24. Smelling feature envy: 4SYMPTOMS
25. Smelling feature envy: Many references to the same object
26. Smelling feature envy: Local variables or params that are used more than instance variables and methods
27. Smelling feature envy: Methods that include a class name in their name
28. Smelling feature envy: Private methods on the same class with the same parameter
29. Extract method: If possible move part of a method to the appropriate class Solution #1
30. Move method: Move the entire method into the right class Solution #2
31. DESIGN PRINCIPLES DESIGN PATTERNS + = CLEAN CODE
32. missing some style
33. Learn the principles patterns Know the use e smells
34. thanks!
36. blog.zamith.pt luís zamith twitter+github: @zamith