Refactoring to Collections

A presentation inspired by Adam Wathan's book "Refactoring to Collections". Presented June 2nd, 2016 @ the Laravel Austin (@LaravelAustin)

Transcript

1. REFACTORING TO COLLECTIONS 1
2. HIGHER ORDER FUNCTIONS A function that takes another function as a parameter, returns a function, or does both. 2
3. "Higher order functions are powerful because they let us create abstractions around common programming patterns" 3
4. FUNCTIONAL BUILDING BLOCKS 4
5. EACH No more than a foreach loop wrapped inside of a higher order function. 5
6. function each($items, $func) { foreach ($items as $item) { $func($item); } } 6
7. Imagine a world without a foreach loop 7
8. function each($items, $func) { for ($i = 0; $i < count($items); $i++) { $func($items[$i]); } } 8
9. MAP Used to transform each item in an array into something else, creating a new array in the process. 9
10. function map($items, $func) { $result = []; foreach ($items as $item) { $result[] = $func($item); } return $result; } 10
11. FILTER Used to filter out any elements of an array that you don't want. 11
12. function filter($items, $func) { $result = []; foreach ($items as $item) { if ($func($item)) { $result[] = $func($item); } } return $result; } 12
13. REJECT A close cousin of filter, that simply flips the conditional to be more expressive. 13
14. REDUCE Used to take some array of items and reduce it down to a single value. 14
15. function reduce($items, $callback, $initial) { $accumulator = $initial; foreach ($items as $item) { $accumulator = $callback($accumulator, $item); } return $accumulator; } 15
16. Speaking of patterns.... 16
17. function map($items, $func) { return reduce($items, function ($mapped, $item) use ($func) { $mapped[] = $func($item); return $mapped; }); } 17
18. THINKING IN STEPS Break a problem into many steps. Turn "I can't because..." into "I could if..." 18
19. THE PROBLEM WITH PRIMITIVES We have to operate on them from the outside by passing them as parameters into other functions. 19
20. $camelString = lcfirst( str_replace(' ', '', ucwords(str_replace('_', ' ', $snakeString)) ) ); 20
21. $camelString = $snakeString->replace('_', ' ') ->ucwords() ->replace(' ', '') ->lcfirst(); 21
22. PRACTICE 22