Added array_key_exists wrapper function

CHANGELOG.md

@@ -6,6 +6,7 @@
     * Added a new `clear_images_by_default` system property to stop cache clear events from removing processed images [#1481](https://github.com/getgrav/grav/pull/1481)
     * Added new `onTwigLoader()` event to enable utilization of loader methods
     * Added new `Twig::addPath()` and `Twig::prependPath()` methods to wrap loader methods and support namespacing [#1604](https://github.com/getgrav/grav/issues/1604)
+    * Added new `array_key_exists()` Twig function wrapper
 1. [](#bugfix)
     * Allow `session.timetout` field to be set to `0` via blueprints [#1598](https://github.com/getgrav/grav/issues/1598)
     

system/src/Grav/Common/Twig/TwigExtension.php

@@ -107,6 +107,7 @@ class TwigExtension extends \Twig_Extension
         return [
             new \Twig_SimpleFunction('array', [$this, 'arrayFunc']),
             new \Twig_SimpleFunction('array_key_value', [$this, 'arrayKeyValueFunc']),
+            new \Twig_SimpleFunction('array_key_exists', [$this, 'arrayKeyExistsFunc']),
             new \Twig_simpleFunction('authorize', [$this, 'authorize']),
             new \Twig_SimpleFunction('debug', [$this, 'dump'], ['needs_context' => true, 'needs_environment' => true]),
             new \Twig_SimpleFunction('dump', [$this, 'dump'], ['needs_context' => true, 'needs_environment' => true]),
@@ -818,6 +819,19 @@ class TwigExtension extends \Twig_Extension
         }
     }
 
+    /**
+     * Check to see if an array key exists
+     *
+     * @param string $key           key of item
+     * @param string $current_array optional array to add to
+     *
+     * @return array
+     */
+    public function arrayKeyExistsFunc($key, $current_array = null)
+    {
+        return array_key_exists($key, $current_array);
+    }
+
     /**
      * Returns a string from a value. If the value is array, return it json encoded
      *