diff --git a/src/Twig/Extension.php b/src/Twig/Extension.php
index d60329fbf7..d6376a1397 100644
--- a/src/Twig/Extension.php
+++ b/src/Twig/Extension.php
@@ -32,6 +32,7 @@ namespace App\Twig;
 
 use Twig\Extension\AbstractExtension;
 use Twig\TwigFunction;
+use Twig\TwigTest;
 
 class Extension extends AbstractExtension
 {
@@ -42,6 +43,13 @@ class Extension extends AbstractExtension
         ];
     }
 
+    public function getTests()
+    {
+        return [
+            new TwigTest('instanceof', [Runtime::class, 'isInstanceOf']),
+        ];
+    }
+
     /**
      * get twig functions
      *
diff --git a/src/Twig/Runtime.php b/src/Twig/Runtime.php
index 5e7554e4a0..129aa9429b 100644
--- a/src/Twig/Runtime.php
+++ b/src/Twig/Runtime.php
@@ -119,11 +119,16 @@ class Runtime implements RuntimeExtensionInterface, EventSubscriberInterface
     public function isFirefox(): bool
     {
         $re_has_chrome = '/.*(?i)\bchrome\b.*/m';
-        $re_has_gecko = '/.*(?i)\bgecko\b.*/m';
+        $re_has_gecko  = '/.*(?i)\bgecko\b.*/m';
         return (preg_match(pattern: $re_has_chrome, subject: $this->request->headers->get('User-Agent')) !== 1)
             && (preg_match(pattern: $re_has_gecko, subject: $this->request->headers->get('User-Agent')) === 1);
     }
 
+    public function isInstanceOf($var, string $instance): bool
+    {
+        return $var instanceof $instance;
+    }
+
     // ----------------------------------------------------------
 
     /**