Clean Code - princípios e práticas para um código sustentável

Palestra sobre Clean Code - princípios e práticas para um código sustentável " apresentada no JsDay 2017 em Feira de Santana

Transcript

1. clean code princípios e práticas para um código sustentável
2. whoami dev na Jusbrasil contribuidor projetos open source
3. código feio
4. function randomNumber() { return 5; }
5. if value is True: doSomething() elif value is False: doSomething2() else: doSomething3()
6. if (x != 0 && x != 1 && x != 2 && x != 3 && x > 4) { doSomething(); }
7. if (player.hasPermission("se.block.smoke")) if (block != Material.LEVER) { if (block != Material.BED) { if (block != Material.BED_BLOCK) { if (block != Material.CACTUS) { if (block != Material.BRICK_STAIRS) { if (block != Material.BIRCH_WOOD_STAIRS) { if (block != Material.BREWING_STAND) { if (block != Material.CAKE) { if (block != Material.CAKE_BLOCK) { if (block != Material.CAULDRON) { if (block != Material.CHEST) { if (block != Material.CLAY) { if (block != Material.SAND) { if (block != Material.BURNING_FURNACE) { if (block != Material.COBBLESTONE_STAIRS) { if (block != Material.FENCE) { if (block != Material.FENCE_GATE) { if (block != Material.FIRE) { if (block != Material.GRAVEL) { if (block != Material.IRON_DOOR_BLOCK) { if (block != Material.IRON_FENCE) { if (block != Material.IRON_DOOR) {
8. if (block != Material.BURNING_FURNACE) { if (block != Material.COBBLESTONE_STAIRS) { if (block != Material.FENCE) { if (block != Material.FENCE_GATE) { if (block != Material.FIRE) { if (block != Material.GRAVEL) { if (block != Material.IRON_DOOR_BLOCK) { if (block != Material.IRON_FENCE) { if (block != Material.IRON_DOOR) { if (block != Material.LADDER) { if (block != Material.MELON) { if (block != Material.LEAVES) { if (block != Material.LOCKED_CHEST) { if (block != Material.SANDSTONE_STAIRS) { if (block != Material.SMOOTH_STAIRS) { if (block != Material.SPRUCE_WOOD_STAIRS) { if (block != Material.TNT) { if (block != Material.WOOD_DOUBLE_STEP) { if (block != Material.WOOD_DOOR) { if (block != Material.WEB) { if (block != Material.ICE) { if (block != Material.SNOW_BLOCK) { if (block != Material.SNOW) { if (block != Material.WATER_LILY) { if (block != Material.TORCH) {
9. if (block != Material.RAILS) { if (block != Material.POWERED_RAIL) { if (block != Material.DETECTOR_RAIL) { if (block != Material.DEAD_BUSH) { if (block != Material.GRASS) { if (block != Material.NETHER_BRICK_STAIRS) { if (block != Material.NETHER_FENCE) { if (block != Material.NETHER_WARTS) { if (block != Material.HUGE_MUSHROOM_1) { if (block != Material.HUGE_MUSHROOM_2) { if (block != Material.BROWN_MUSHROOM) { if (block != Material.GLASS) { if (block != Material.JUNGLE_WOOD_STAIRS) { if (block != Material.WATER) { if (block != Material.SUGAR_CANE_BLOCK) { if (block != Material.WOOD_DOUBLE_STEP) { if (block != Material.WALL_SIGN) { if (block != Material.WOOD_PLATE) { if (block != Material.STONE_PLATE) { if (block != Material.STONE_BUTTON) { if (block != Material.WOOD_STAIRS) { if (block != Material.TRAP_DOOR) { if (block != Material.TRIPWIRE) { if (block != Material.TRIPWIRE_HOOK) { if (block != Material.WOOD_STEP) { if (block != Material.THIN_GLASS) { if (block != Material.REDSTONE_TORCH_OFF) { if (block != Material.REDSTONE_TORCH_ON) { if (block != Material.SAPLING) { String s = new SerializableLocation(loc).unpack().toString(); this.plugin.Blindeness.add(s); this.plugin.Blindeness.save(); if (this.String1 == this.plugin.getConfig().getString("_Block_Blindeness")) { player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] You Created a" + ChatColor.DARK_RED + " BlindenessEffectBlock" + ChatColor.DARK_GREEN + " at " + ChatColor.RED + s); } else { player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] You Created a" + ChatColor.DARK_RED + " BlindenessEffectBlock" + ChatColor.DARK_GREEN + " at " + ChatColor.RED + s); } } else { player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else
10. if (block != Material.RAILS) { if (block != Material.POWERED_RAIL) { if (block != Material.DETECTOR_RAIL) { if (block != Material.DEAD_BUSH) { if (block != Material.GRASS) { if (block != Material.NETHER_BRICK_STAIRS) { if (block != Material.NETHER_FENCE) { if (block != Material.NETHER_WARTS) { if (block != Material.HUGE_MUSHROOM_1) { if (block != Material.HUGE_MUSHROOM_2) { if (block != Material.BROWN_MUSHROOM) { if (block != Material.GLASS) { if (block != Material.JUNGLE_WOOD_STAIRS) { if (block != Material.WATER) { if (block != Material.SUGAR_CANE_BLOCK) { if (block != Material.WOOD_DOUBLE_STEP) { if (block != Material.WALL_SIGN) { if (block != Material.WOOD_PLATE) { if (block != Material.STONE_PLATE) { if (block != Material.STONE_BUTTON) { if (block != Material.WOOD_STAIRS) { if (block != Material.TRAP_DOOR) { if (block != Material.TRIPWIRE) { if (block != Material.TRIPWIRE_HOOK) { if (block != Material.WOOD_STEP) { if (block != Material.THIN_GLASS) { if (block != Material.REDSTONE_TORCH_OFF) { if (block != Material.REDSTONE_TORCH_ON) { if (block != Material.SAPLING) { String s = new SerializableLocation(loc).unpack().toString(); this.plugin.Blindeness.add(s); this.plugin.Blindeness.save(); if (this.String1 == this.plugin.getConfig().getString("_Block_Blindeness")) { player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] You Created a" + ChatColor.DARK_RED + " BlindenessEffectBlock" + ChatColor.DARK_GREEN + " at " + ChatColor.RED + s); } else { player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] You Created a" + ChatColor.DARK_RED + " BlindenessEffectBlock" + ChatColor.DARK_GREEN + " at " + ChatColor.RED + s); } } else { player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else player.sendMessage(ChatColor.DARK_GREEN + "[SpecialEffects] Can't" + ChatColor.DARK_RED + " create a EffectBlock" + ChatColor.DARK_GREEN + " Using this material"); } else
11. http://codecrap.com/
12. who?
14. código feio é um problema?
15. computadores não ligam para beleza
16. ninguém vai ler, só eu!
17. é só uma poc
18. é rapidinho, depois eu mudo
19. CHUCK NORRIS IS WATCHING YOU
20. código limpo legível e reusável
21. regra do escoteiro
22. don’t repeat yourself
23. keep it simple
24. seja o autor do seu código
25. práticas
26. nomes
27. use nomes pronunciáveis
28. let x = “http://j.us”;
29. let encurtadorURL = “http://api.j.us”;
30. use nomes buscáveis
31. setTimeout(notifyUser, 120);
32. const TWO_MINUTES = 120; setTimeout(notifyUser, TWO_MINUTES);
33. use nomes claros
34. function calcula(valor) { return valor * 1.1; }
35. function calculaGorjeta(valor) { return valor * 1.1; }
36. funções
37. funções devem fazer apenas uma coisa
38. function notifyClients(clients) { clients.forEach(clientId) => { const client = db.find(clientId); if (client.isActive()) { notify(client); } } }
39. function notifyActiveClients(clients) { client.filter(isActive).forEach(notify); } function isActive(clientId) { const client = db.find(clientId); return client.isActive(); }
40. não use flags como parâmetros
41. function createUser(user, isAdmin) { db.save(user); if (isAdmin) { promoteUser(user); } }
42. function createUser(user) { db.save(user); } function createAdmin(user) { createUser(user); promoteUser(user); }
43. objetos
44. Single Responsibility Principle (SRP)
45. class UserSettings { constructor(user) { this.user = user; } changeSettings(settings) { if (this.verifyCredentials()) { … } } verifyCredentials() { … } }
46. class UserFriends { constructor(user) { this.user = user; } addFriends(friend) { if (this.verifyCredentials()) { … } } verifyCredentials() { … } }
47. class UserAuth { constructor(user) { this.user = user; } verifyCredentials() { … } } class UserSettings { constructor(user) { this.user = user; this.auth = new UserAuth(user); } changeSettings(settings) { if (this.auth.verifyCredentials()) { … } } }
48. cuidados gerais
49. código duplicado
50. variáveis não usadas
51. “unreachable” code
52. console.log
53. …
54. linter
55. linter
56. Testes
57. testes são códigos para verificar que seu código está funcionando como esperado
58. func testeSoma() { let resultado = soma(1, 1); expect(resultado).toBe(2); }
59. func testeSplitHostAndPort() { let url = “jusbrasil.com.br:3333”; let {host, port} = splitHostAndPort(url); expect(host).toBe(“jusbrasil.com.br”); expect(port).toBe(3333); }
60. testes me deixam mais lento?
61. TDD
63. testes ajudam a manter a manutenção e o reuso do código
64. Com TDD todo código novo nasce com testes
65. TDD ajuda a focar na resolução do problema
66. func testLogin() { let user = db.find(userId); user.login(password); assert(user.isLogged()); }
67. func testBot() { let bot = new Bot(); expect(bot.x).toBe(0); expect(bot.y).toBe(0); bot.walkToLeft(5); expect(bot.x).toBe(-5); }
69. coding style
70. const semEstilo = { foo: 3, 'bar': 4, 'data-blah': 5, };
71. const comEstilo = { foo: 3, bar: 4, data-blah: 5, };
72. • airbnb • Google • Mozilla • Idiomatic.js • jQuery Core • Node.js • …
73. type check TypeScript Flow
74. // @flow function square(n: number): number { return n * n; } square("2"); // Error!
75. Coding Dojo
76. code review
77. legado???
78. legado +6 meses sem manutenção deploy não funcionava 33% cobertura de testes
79. livros
80. ????
81. @andrewsmedina github.com/andrewsmedina twitter.com/andrewsmedina
82. perguntas?