[9.x] Add missing method to View/ComponentAttributeBag (#45016)

* add 'missing' method ComponentAttributeBag

* add tests for ComponentAttributeBag for 'has' and 'missing'

* code style

* Update ComponentAttributeBag.php

Co-authored-by: Taylor Otwell <taylor@laravel.com>

src/Illuminate/View/ComponentAttributeBag.php

@@ -69,6 +69,17 @@ public function has($key)
         return array_key_exists($key, $this->attributes);
     }
 
+    /**
+     * Determine if a given attribute is missing from the attribute array.
+     *
+     * @param  string  $key
+     * @return bool
+     */
+    public function missing($key)
+    {
+        return ! $this->has($key, $this->attributes);
+    }
+
     /**
      * Only include the given attribute from the attribute array.
      *

tests/View/ViewComponentAttributeBagTest.php

@@ -94,4 +94,14 @@ public function testAttributeRetrieval()
             'test-extract-2' => 'defaultValue',
         ]));
     }
+
+    public function testAttibuteExistence()
+    {
+        $bag = new ComponentAttributeBag(['name' => 'test']);
+
+        $this->assertTrue((bool) $bag->has('name'));
+        $this->assertFalse((bool) $bag->missing('name'));
+        $this->assertFalse((bool) $bag->has('class'));
+        $this->assertTrue((bool) $bag->missing('class'));
+    }
 }