Added key parameter to filter strategy callback.

Updated documentation for filter strategy.

Author: Paul

README.md

@@ -518,7 +518,7 @@ Filter(Strategy|Mapping|array|mixed $expression, callable $callback = null)
 ```
 
  1. `$expression` – Expression.
- 2. `$callback` – Callback function that receives the current value as its first argument.
+ 2. `$callback` – Callback function that receives the current value as its first argument, the current key as its second argument and context as its third argument.
 
 #### Example
 

src/Strategy/Filter.php

@@ -4,15 +4,19 @@
 use ScriptFUSION\Mapper\Mapping;
 
 /**
- * Filters null values or values rejected by the specified callback
+ * Filters null values or values rejected by the specified callback.
  */
 class Filter extends Delegate
 {
+ /**
+ * @var callable|null
+ */
  private $callback;
 
  /**
  * @param Strategy|Mapping|array|mixed $expression Expression.
- * @param callable|null $callback Callback function that receives the current value as its first argument.
+ * @param callable|null $callback Callback function that receives the current value as its first argument, the
+ * current key as its second argument and context as its third argument.
  */
  public function __construct($expression, callable $callback = null)
  {
@@ -27,18 +31,20 @@ public function __invoke($data, $context = null)
  return null;
  }
 
- $filter = function (array $data, $context) {
- $callback = $this->callback ?: function ($value) {
- return $value !== null;
- };
+ return iterator_to_array(self::filter($this->callback ?: [$this, 'filterNulls'], $data, $context));
+ }
 
- foreach ($data as $datum) {
- if ($callback($datum, $context)) {
- yield $datum;
- }
+ private static function filter(callable $callback, array $data, $context)
+ {
+ foreach ($data as $key => $datum) {
+ if ($callback($datum, $key, $context)) {
+ yield $key => $datum;
  }
- };
+ }
+ }
 
- return iterator_to_array($filter($data, $context));
+ private static function filterNulls($value)
+ {
+ return $value !== null;
  }
 }

test/Unit/Mapper/Strategy/FilterTest.php

@@ -12,32 +12,38 @@ final class FilterTest extends \PHPUnit_Framework_TestCase
  public function testDefaultCallback()
  {
  $filter = new Filter(null);
- $filter->setMapper(MockFactory::mockMapper([null, 0, "0", null]));
+ $filter->setMapper(MockFactory::mockMapper([null, 0, '0', null]));
 
- self::assertEquals([0, "0"], array_values($filter([])));
+ self::assertSame([1 => 0, 2 => '0'], $filter([]));
  }
 
- public function testCustomCallback()
+ public function testFilterByValue()
  {
  $filter = new Filter(null, function ($value) {
  return $value['foo'] === 'bar';
  });
 
  $filter->setMapper(MockFactory::mockMapper([
- [
- 'foo' => 'bar',
- ],
- [
- 'foo' => 'baz',
- ],
+ $bar = ['foo' => 'bar'],
+ ['foo' => 'baz'],
  ]));
 
- self::assertEquals([['foo' => 'bar']], $filter([]));
+ self::assertSame([$bar], $filter([]));
+ }
+
+ public function testFilterByKey()
+ {
+ $filter = new Filter(null, function ($_, $key) {
+ return $key % 2;
+ });
+ $filter->setMapper(MockFactory::mockMapper(range('a', 'e')));
+
+ self::assertSame([1 => 'b', 3 => 'd'], $filter([]));
  }
 
  public function testContextPassed()
  {
- $filter = new Filter(null, function ($_, $context) {
+ $filter = new Filter(null, function ($_, $__, $context) {
  self::assertSame('foo', $context);
  });
  $filter->setMapper(MockFactory::mockMapper(['bar']));