It's my way or the highway - How to make your code usable by others

With npm, composer, gem, pip and numerous other package managers, we have more libraries at our disposal then ever before.

The problem with a lot of those libraries is that they address just one aspect: functionality, neglecting another important one: the developer who is implementing the library.

Did you ever find yourself at 3AM, scrolling through pages and pages of documentation, wishing you wrote a piece of code on your own instead of waisting your time implementing someone elses? During this talk we will go over a couple of OOP principles and design patterns that will greatly reduce someones time when implementing something you wrote, while increasing the quality of the code in general.

Transcript

1. Hi
2. I am a developer
3. I ! sometimes @BogdanHabic
5. It’s my way or the highway How to make your code usable by others
7. curl -sS https://getcomposer.org/installer | php
8. sudo gem install cocoapods
9. brew install node
10. composer require nesbot/carbon gem install rails -v 4.2.4 pod 'GoogleMaps' npm install express pip install -e django/
12. AR DDD SOLID DRY TDD
13. BDD DDD Law of Demeter AOP EE
15. Inheritance Encapsulation Polymorphism
16. Why does it come to this?
17. • Cowboy coding • Tight deadlines • “ I’ll refactor this later ”
18. function doWork2(idLinije) { httpObject = GetXmlHttpObject(); if (httpObject != null) { var url = "comboLinije.php" //url = url + "?idLinije=" + idLinije; //url= url + "&smer" + smer; url = url + "?kodLinije=" + idLinije httpObject.open("GET", url ,true); httpObject.send(null); httpObject.onreadystatechange = setOutput2; } }
19. Bad design
20. global $wpdb;
21. How can we fix this?
22. “I’ll refactor this later” = “We can still be friends”
23. DRY
24. SOLID
25. Object Calisthenics
26. Design patterns
29. • Only One Level Of Indentation Per Method
 • Don't Use The ELSE Keyword
 • Wrap All Primitives And Strings
30. • First Class Collections • One Dot Per Line • Don't Abbreviate
31. • Keep All Entities Small
 • No Classes With More Than Two Instance Variables
 • No Getters/Setters/Properties
32. What makes a piece of code: “ Nice to use ”
33. Easy to implement
34. It’s eloquent
35. com.sun.java.swing.plaf.nim bus.InternalFrameInternalF rameTitlePaneInternalFram eTitlePaneMaximizeButton WindowNotFocusedState
36. Internal frame internal frame, title pane, internal frame. title pane maximize button window not focused state
37. It just
 WORKS
38. How to write code that just
 WORKS ?
39. The Developer should not care about the internals
40. The code should “ lead ” the Developer
41. The behavior should be easily changeable by the Developer
42. • Interfaces • Abstract classes • Traits • Exceptions
43. • Strategy • Command Bus
45. Here is all the paperwork needed.
46. interface StringDecorator { /** * Decorates the string. * * @param string $string * @return string */ public String decorate($string); }
47. • Known “ consumption “ • Expected behavior • It’s self explanatory
48. Abstract classes
49. abstract class RegexDecorator implements StringDecorator { protected $regularExpression; protected $replacement; public final function __construct() { $this->regularExpression = $this->getRegularExpression(); $this->replacement = $this->getReplacement(); } public abstract function getRegularExpression(); public abstract function getReplacement(); protected function replace($string) { return preg_replace($this->regularExpression, $this->replacement, $string); } public function decorate($string) { return $this->replace($string); } }
50. abstract class RegexDecorator implements StringDecorator {
51. protected $regularExpression; protected $replacement;
52. public abstract function getRegularExpression(); public abstract function getReplacement();
53. protected function replace($string) { return preg_replace($this->regularExpression, $this->replacement, $string); }
54. public function decorate($string) { return $this->replace($string); }
55. public final function __construct() { $this->regularExpression = $this->getRegularExpression(); $this->replacement = $this->getReplacement(); }
56. abstract class RegexDecorator implements StringDecorator { protected $regularExpression; protected $replacement; public final function __construct() { $this->regularExpression = $this->getRegularExpression(); $this->replacement = $this->getReplacement(); } public abstract function getRegularExpression(); public abstract function getReplacement(); protected function replace($string) { return preg_replace($this->regularExpression, $this->replacement, $string); } public function decorate($string) { return $this->replace($string); } }
57. • Forced to declare attributes • Known “ consumption “ • Expected behavior • It’s self explanatory
58. Traits
59. trait StringDecoratorTrait { public function decorate($string) { foreach($this->getDecorators() as $decorator) { $decoratorInstance = new $decorator(); $string = $decoratorInstance->decorate($string); } return $string; } abstract public function getDecorators(); }
60. class MyDecoratorQueue { use StringDecoratorTrait; public function getDecorators() { return [ 'App\Decorators\FirstCapitalLetter', 'App\Decorators\ReplaceSpacesWithUnderscores', 'App\Decorators\LastLetterSmall', ]; } }
61. • It’s modular • It’s extendible • It’s simple
62. Exceptions
63. It’s OK to break someones code
64. public function decorate($string) { foreach($this->getDecorators() as $decorator) { $decoratorInstance = new $decorator(); $string = $decoratorInstance->decorate($string); if(!is_string($string)) throw new Exception(“The return value should be a string”); } return $string; }
66. The •
67. Developer UX
69. Strategy
70. Command Bus
71. Bogdan Habić
72. Računarski fakultet
74. Thank you
75. https://joind.in/15224 @BogdanHabic