Código limpio sin loops

https://github.com/joecohens/collections-challenge

Transcript

1. CÓDIGO LIMPIO SIN LOOPS JOSEPH COHEN @JOECOHENS
2. UN POCO DE MI... CEO @SHOPERTI CTO @DINKBIT DEV @ALTTHREE
3. $totalSalesByItem = 0; foreach ($customers as $customer) { $countryCode = $customer->country; if ($countryCode == 'MEX') { $orders = $customer->orders; foreach ($orders as $order) { if ($order->status == 'paid') { foreach ($order->items as $item) { $totalSalesByItem += $item->total; } } } } } return '$'.number_format($totalSalesByItem, 2);
5. UN POCO DE TEORÍA
6. CÓDIGO IMPERATIVO VS DECLARATIVO
7. IMPERATIVO
8. function getUsersEmails($users) { $emails = []; for ($i = 0; $i < count($users); $i++) { $user = $users[$i]; if ($user->email !== null) { $emails[] = $user->email; } } return $emails; }
9. DECLARATIVO
10. SQL SELECT email FROM users WHERE email IS NOT NULL
11. FUNCIONES DE ORDEN SUPERIOR (HIGHER ORDER FUNCTIONS)
12. JQUERY $("#btn").click(function() { alert("PELIGRO!"); });
13. $router->get('/home', function() { return 'PELIGRO!'; });
14. BUSCANDO PATRONES
15. $emails = []; foreach ($users as $user) { $email = $user->getEmail(); $emails[] = $email; } return $emails;
16. $cartTotals = []; foreach ($cart->items as $item) { $product = [ 'id' => $item->id, 'name' => $item->name, 'total' => $item->quantity * $item->price, ]; $cartTotals[] = $product; } return $cartTotals;
17. // $emails = []; // foreach ($users as $user) { $email = $user->getEmail(); $emails[] = $email; // } // return $emails;
18. // $cartTotals = []; // foreach ($cart->items as $item) { $product = [ 'id' => $item->id, 'name' => $item->name, 'total' => $item->quantity * $item->price, ]; $cartTotals[] = $product; } // return $cartTotals;
19. $results = []; foreach ($items as $item) { $result = [ // 'id' => $item->id, // 'name' => $item->name, // 'total' => $item->quantity * $item->price, ]; $results[] = $result; } return $results;
20. $results = []; foreach ($items as $item) { $result = // $user->getEmail(); $results[] = $result; } return $results;
21. FUNCIONES ANÓNIMAS PHP < 5.3 (YA ESTAMOS EN 7)
23. $callback = function ($item) { return $item->getEmail(); }; // $results = []; // foreach ($items as $item) { $result = $callback($item); // $results[] = $result; // } // return $results;
24. $callback = function ($item) { return [ 'id' => $item->id, 'name' => $item->name, 'total' => $item->quantity * $item->price, ]; }; // $results = []; // foreach ($items as $item) { $result = $callback($item); // $results[] = $result; } // return $results;
25. function map($items, $func) { $results = []; foreach ($items as $item) { $result = $func($item); $results[] = $result; } return $results; }
26. $emails = map($users, function ($user) { return $user->getEmail(); })
27. OTRO EJEMPLO DE HIGHER ORDER FUNCTIONS
28. function each($items, $func) { for ($i = 0; $i < count($items); $i++) { $func($items[$i]); } }
29. function each($items, $func) { foreach ($items as $item) { $func($item); } }
30. for ($i = 0; $i < count($productsToDelete); $i++) { $productsToDelete[$i]->delete(); }
31. each($productsToDelete, function ($product) { $product->delete(); });
32. DIFERENCIA ENTRE MAP Y EACH
33. // Mal! Debes de usar `map`. each($customers, function ($customer) use (&$emails) { $emails[] = $customer->email; }); // Bien! $emails = map($customers, function ($customer) { return $customer->email; });
34. UN EJEMPLO MÁS
35. $admins = []; foreach ($users as $user) { if ($user->isAdmin()) { $admins[] = $user; } } return $admins;
36. $activeUsers = []; foreach ($users as $user) { if ($user->status == 'active') { $activeUsers[] = $user; } } return $activeUsers;
37. // $admins = []; // foreach ($users as $user) { if ($user->isAdmin()) { // $admins[] = $user; } // } // return $admins;
38. // $activeUsers = []; // foreach ($users as $user) { if ($user->status == 'active') { // $activeUsers[] = $user; } // } // return $activeUsers;
39. $callback = function ($item) { return $item->isAdmin(); } // $results = []; // foreach ($items as $item) { if ($callback($item)) { // $results[] = $item; } // } // return $results;
40. $callback = function ($item) { return $item->status == 'active'; } // $results = []; // foreach ($items as $item) { if ($callback($item)) { // $results[] = $item; } // } // return $results;
41. $activeUsers = filter($users, function ($item) { return $item->status == 'active'; });
42. NATIVOS
43. NATIVOS > for
44. NATIVOS > for > foreach
45. NATIVOS > for > foreach > array_map
46. NATIVOS > for > foreach > array_map > array_filter
47. NATIVOS > for > foreach > array_map > array_filter > ...
48. EJEMPLO
49. function getActiveUsersEmails($users) { $emails = []; foreach ($users as $user) { if ($user->status == 'active') { $emails[] = $user->email; } } return $emails; }
50. PARTIENDO EN PASOS
51. // function getActiveUsersEmails($users) // { $activeUsers = array_filter($users, function ($user) { return $user->status == 'active'; }); // $emails = []; // foreach ($users as $user) { // if ($user->status == 'active') { // $emails[] = $user->email; // } // } // return $emails; // }
52. // function getActiveUsersEmails($users) // { // $activeUsers = array_filter($users, function ($user) { // return $user->status == 'active'; // }); $emails = []; foreach ($activeUsers as $user) { $emails[] = $user->email; } return $emails; // }
54. function getActiveUsersEmails($users) { $activeUsers = array_filter($users, function ($user) { return $user->status == 'active'; }); $emails = array_map(function ($user) { return $user->email; }, $activeUsers); return $emails; }
55. // function getActiveUsersEmails($users) // { $activeUsers // = array_filter($users, function ($user) { // return $user->status == 'active'; // }); // $emails = array_map(function ($user) { // return $user->email; }, $activeUsers); // return $emails; // }
56. function getActiveUsersEmails($users) { return array_map(function ($user) { return $user->email; }, array_filter($users, function ($user) { return $user->status == 'active'; })); }
58. INTRODUCCIÓN A COLECCIONES
59. class Collection { protected $items; public function __construct($items) { $this->items = $items; } public function map($callback) { return new static(array_map($callback, $this->items)); } public function filter($callback) { return new static(array_filter($this->items, $callback)); } public function toArray() { return $this->items; } }
60. PIPELINES (MI COSA FAVORITA)
61. function getActiveUsersEmails($users) { return (new Collection($users))->filter(function ($user) { return $user->status == 'active'; })->map(function($users)) { return $user->email; })->toArray(); }
62. // class Collection // { // protected $items; // // public function __construct($items) // { // $this->items = $items; // } public static function make($items) { return new static($items); } // ...
63. function getActiveUsersEmails($users) { return Collection::make($users)->filter(function ($user) { return $user->status == 'active'; })->map(function($users)) { return $user->email; })->toArray(); }
64. INMUTABILIDAD
65. // class Collection // { // .. public function map($callback) { return new static(array_map($callback, $this->items)); } public function filter($callback) { return new static(array_filter($this->items, $callback)); } // ... // }
66. USANDO COLECCIONES COMO ARRAYS
67. IMPLEMENTAR INTERFACES EN COLLECTION
68. IMPLEMENTAR INTERFACES EN COLLECTION > ArrayAccess
69. IMPLEMENTAR INTERFACES EN COLLECTION > ArrayAccess > Countable
70. IMPLEMENTAR INTERFACES EN COLLECTION > ArrayAccess > Countable > IteratorAggregate
71. class Collection implements ArrayAccess, Countable, IteratorAggregate { protected $items; public function __construct($items) { $this->items = $items; } public function offsetExists($offset) { return array_key_exists($offset, $this->items); } public function offsetGet($offset) { return $this->items[$offset]; } public function offsetSet($offset, $value) { if ($offset === null) { $this->items[] = $value; } else { $this->items[$offset] = $value; } } public function offsetUnset($offset) { unset($this->items[$offset]); } public function count() { return count($this->items); } public function getIterator() { return new ArrayIterator($this->items); } }
72. $items = Collection::make([ 'Rasmus' => 'Lerdof', 'Adam' => 'Watham', 'Joe' => 'Cohen', ]); echo $items[2]; // => Joe Cohen echo count($items); // => 3
74. Toda la librería de Illuminate Support composer require illuminate/support Sólo las colecciones composer require tightenco/collect
75. CHALLENGE 1 1 https://github.com/joecohens/collections-challenge.git
76. ➜ example git:(master) php problem.php $360,273.00
77. <?php $data = file_get_contents(__DIR__.'/stubs/data.json'); $customers = json_decode($data); $totalSalesByItem = 0; foreach ($customers as $customer) { $countryCode = $customer->country; if ($countryCode == 'MEX') { $orders = $customer->orders; foreach ($orders as $order) { if ($order->status == 'paid') { foreach ($order->items as $item) { $totalSalesByItem += $item->total; } } } } } echo '$'.number_format($totalSalesByItem, 2)."\n";
78. <?php require __DIR__.'/vendor/autoload.php'; $data = file_get_contents(__DIR__.'/stubs/data.json'); $customers = new \Illuminate\Support\Collection(json_decode($data));
79. $totalSalesByItem = $customers->filter(function ($customer) { return $customer->country == 'MEX'; })->flatMap(function ($customer) { return $customer->orders; })->filter(function ($order) { return $order->status == 'paid'; })->flatMap(function ($order) { return $order->items; })->reduce(function ($carry, $item) { return $carry + $item->total; }); echo '$'.number_format($totalSalesByItem, 2)."\n";
80. $customers = json_decode($data); $totalSalesByItem = 0; foreach ($customers as $customer) { $countryCode = $customer->country; if ($countryCode == 'MEX') { $orders = $customer->orders; foreach ($orders as $order) { if ($order->status == 'paid') { foreach ($order->items as $item) { $totalSalesByItem += $item->total; } } } } } echo '$'.number_format($totalSalesByItem, 2)."\n";
81. ➜ example git:(master) php solution.php $360,273.00
82. BIBLIOGRAFÍA POR @ADAMWATHAN Refactoring to Collections https://adamwathan.me/refactoring- to-collections/ Ejemplos, casos prácticos y más.
83. Haz lo que más te gusta y harás cosas increíbles — Joseph Cohen
84. GRACIAS JOSEPH COHEN @JOECOHENS CEO @SHOPERTI & CTO @DINKBIT DEV @ALTTHREE