From ae9ada9dbb90362596f41bc1300b319245b44fe3 Mon Sep 17 00:00:00 2001
From: Simon Podlipsky <simon@podlipsky.net>
Date: Wed, 27 Mar 2024 13:32:25 +0100
Subject: [PATCH] feat: add support for filtering using key

---
 src/IterableObject.php       |  8 ++++++--
 src/iterable-functions.php   |  2 +-
 tests/IterableFilterTest.php | 26 ++++++++++++++++++++++++++
 3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/src/IterableObject.php b/src/IterableObject.php
index 6a987ff..c36f7f6 100644
--- a/src/IterableObject.php
+++ b/src/IterableObject.php
@@ -16,6 +16,8 @@
 use function array_map;
 use function iterator_to_array;
 
+use const ARRAY_FILTER_USE_BOTH;
+
 /**
  * @internal
  *
@@ -40,7 +42,7 @@ public function __construct(iterable $iterable, bool $preserveKeys = true)
     }
 
     /**
-     * @param (callable(TValue):bool)|null $filter
+     * @param (callable(TValue):bool)|(callable(TValue,TKey):bool)|null $filter
      *
      * @return self<TKey, TValue>
      */
@@ -56,7 +58,9 @@ static function ($value): bool {
             return new self(new CallbackFilterIterator(new IteratorIterator($this->iterable), $filter));
         }
 
-        $filtered = $filter === null ? array_filter($this->iterable) : array_filter($this->iterable, $filter);
+        $filtered = $filter === null
+            ? array_filter($this->iterable)
+            : array_filter($this->iterable, $filter, ARRAY_FILTER_USE_BOTH);
 
         return new self($filtered);
     }
diff --git a/src/iterable-functions.php b/src/iterable-functions.php
index 1253042..239eb3e 100644
--- a/src/iterable-functions.php
+++ b/src/iterable-functions.php
@@ -87,7 +87,7 @@ function iterable_to_traversable(iterable $iterable): Traversable
 /**
  * Filters an iterable.
  *
- * @param (callable(TValue):bool)|null $filter
+ * @param (callable(TValue):bool)|(callable(TValue,TKey):bool)|null $filter
  *
  * @psalm-param iterable<TKey, TValue> $iterable
  * @psalm-return iterable<TKey, TValue>
diff --git a/tests/IterableFilterTest.php b/tests/IterableFilterTest.php
index ea0b4ca..e7b1d6a 100644
--- a/tests/IterableFilterTest.php
+++ b/tests/IterableFilterTest.php
@@ -4,6 +4,7 @@
 
 namespace BenTools\IterableFunctions\Tests;
 
+use Generator;
 use SplFixedArray;
 use Traversable;
 
@@ -47,3 +48,28 @@ static function ($input): bool {
     assert($filtered instanceof Traversable);
     assertSame([1 => 'bar'], iterator_to_array($filtered));
 });
+
+it('filters a Traversable object with a callback using key', function (): void {
+    $iterable = (function (): Generator {
+        yield 'foo' => 1;
+        yield 'bar' => 1;
+    })();
+    $filter =
+    static function (int $input, string $key): bool {
+        return $key === 'bar';
+    };
+    $filtered = iterable_filter($iterable, $filter);
+    assert($filtered instanceof Traversable);
+    assertSame(['bar' => 1], iterator_to_array($filtered));
+});
+
+it('filters an array with a callback using key', function (): void {
+    $iterable = ['foo' => 1, 'bar' => 1];
+    $filter =
+    static function (int $input, string $key): bool {
+        return $key === 'bar';
+    };
+    $filtered = iterable_filter($iterable, $filter);
+    assert($filtered instanceof Traversable);
+    assertSame(['bar' => 1], iterator_to_array($filtered));
+});