From 4fc0ea5389424876bdbd858bbb3df97e9adc0b28 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateus=20Guimar=C3=A3es?= <mateus.jatene@gmail.com>
Date: Mon, 22 May 2017 12:28:01 -0300
Subject: [PATCH] add intersect by keys method to collections

---
 src/Illuminate/Support/Collection.php   | 11 +++++++++++
 tests/Support/SupportCollectionTest.php | 12 ++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/src/Illuminate/Support/Collection.php b/src/Illuminate/Support/Collection.php
index ad3d258f0656..cb5868218160 100644
--- a/src/Illuminate/Support/Collection.php
+++ b/src/Illuminate/Support/Collection.php
@@ -658,6 +658,17 @@ public function intersect($items)
         return new static(array_intersect($this->items, $this->getArrayableItems($items)));
     }
 
+    /**
+     * Intersect the collection with the given items by key
+     * 
+     * @param  mixed  $items
+     * @return static
+     */
+    public function intersectByKeys($items)
+    {
+        return new static(array_intersect_key($this->items, $this->getArrayableItems($items)));
+    }
+
     /**
      * Determine if the collection is empty or not.
      *
diff --git a/tests/Support/SupportCollectionTest.php b/tests/Support/SupportCollectionTest.php
index f02d55053606..59fdafbb8f09 100755
--- a/tests/Support/SupportCollectionTest.php
+++ b/tests/Support/SupportCollectionTest.php
@@ -570,6 +570,18 @@ public function testIntersectCollection()
         $this->assertEquals(['first_word' => 'Hello'], $c->intersect(new Collection(['first_world' => 'Hello', 'last_word' => 'World']))->all());
     }
 
+    public function testIntersectByKeysNull()
+    {
+        $c = new Collection(['name' => 'Mateus', 'age' => 18]);
+        $this->assertEquals([], $c->intersectByKeys(null)->all());
+    }
+
+    public function testIntersectByKeys()
+    {
+        $c = new Collection(['name' => 'Mateus', 'age' => 18]);
+        $this->assertEquals(['name' => 'Mateus'], $c->intersectByKeys(new Collection(['name' => 'Mateus', 'surname' => 'Guimaraes']))->all());
+    }
+
     public function testUnique()
     {
         $c = new Collection(['Hello', 'World', 'World']);