From 7577986980b9e80473e3e0f3d00e01a55e1087f5 Mon Sep 17 00:00:00 2001
From: Oliver Vogel <oliver@olivervogel.com>
Date: Sat, 30 Sep 2023 16:48:34 +0200
Subject: [PATCH] Add filter method to Collection

---
 src/Collection.php       | 15 +++++++++++++++
 tests/CollectionTest.php | 10 ++++++++++
 2 files changed, 25 insertions(+)

diff --git a/src/Collection.php b/src/Collection.php
index 5434f83bc..76e35b139 100644
--- a/src/Collection.php
+++ b/src/Collection.php
@@ -134,6 +134,21 @@ public function map(callable $callback): self
         return new self($items);
     }
 
+    /**
+     * Run callback on each item of the collection an remove it if it does not return true
+     *
+     * @param callable $callback
+     * @return Collection
+     */
+    public function filter(callable $callback): self
+    {
+        $items = array_filter($this->items, function ($item) use ($callback) {
+            return $callback($item);
+        });
+
+        return new self($items);
+    }
+
     public function pushEach(array $data, ?callable $callback = null): CollectionInterface
     {
         if (! is_iterable($data)) {
diff --git a/tests/CollectionTest.php b/tests/CollectionTest.php
index 9703486ef..67488a62e 100644
--- a/tests/CollectionTest.php
+++ b/tests/CollectionTest.php
@@ -45,6 +45,16 @@ public function testCount()
         $this->assertEquals(3, count($collection));
     }
 
+    public function testFilter()
+    {
+        $collection = new Collection(['foo', 'bar', 'baz']);
+        $this->assertEquals(3, $collection->count());
+        $collection = $collection->filter(function ($text) {
+            return substr($text, 0, 1) == 'b';
+        });
+        $this->assertEquals(2, $collection->count());
+    }
+
     public function testFirstLast()
     {
         $collection = new Collection(['foo', 'bar', 'baz']);