Add ability to check existence of multiple keys

README.md

@@ -20,7 +20,7 @@ Import any function with `use function Equip\Arr\func;`.
 
 ### List of functions
 
-`exists($source, $key)` check if a key exists in an array.
+`exists($source, $keys)` check if a key or keys exist in an array.
 
 `to_array($value)` convert a value to an array.
 

src/array.php

@@ -5,16 +5,19 @@
 use Traversable;
 
 /**
- * Check if a key exists in an array.
+ * Check if a key or keys exist in an array.
  *
  * @param array|Traversable $array
- * @param string|integer $key
+ * @param string|integer|array $keys
  *
  * @return boolean
  */
-function exists($array, $key)
+function exists($array, $keys)
 {
-    return array_key_exists($key, to_array($array));
+    $keys = to_array($keys);
+
+    $intersection = array_intersect_key(to_array($array), array_flip($keys));
+    return count($intersection) === count($keys);
 }
 
 /**

tests/ArrayTest.php

@@ -156,6 +156,29 @@ public function testTail()
         $this->assertSame(['c'], tail($this->list));
     }
 
+    public function testExists()
+    {
+        // Works with single keys
+        $this->assertTrue(exists($this->hash, 'company'));
+        $this->assertTrue(exists($this->list, 1));
+        $this->assertFalse(exists($this->hash, 'missing'));
+        $this->assertFalse(exists($this->list, 10));
+
+        // Works with arrays of keys
+        $this->assertTrue(exists($this->hash, ['company', 'owner']));
+        $this->assertTrue(exists($this->list, [0, 2]));
+
+        // False if not all keys are present
+        $this->assertFalse(exists($this->hash, ['company', 'missing']));
+        $this->assertFalse(exists($this->list, [0, 10]));
+
+        // Works with empty arrays
+        $this->assertFalse(exists([], 'missing'));
+        $this->assertFalse(exists([], 10));
+        $this->assertFalse(exists([], ['missing', 'also missing']));
+        $this->assertTrue(exists([], []));
+    }
+
     public function testToArray()
     {
         // Works with arrays