add json decode filter to twig

Documentation/Manual.rst

@@ -5450,6 +5450,19 @@ using the `qfqlink` filter::
 
 will render a link to *http://www.example.com*.
 
+Json Decode
+^^^^^^^^^^^
+A String can be JSON decoded in Twig the following way::
+
+  {% set decoded = '["this is one", "this is two"]' | json_decode%}
+
+This can then be used as a normal object in Twig::
+
+  {{ decoded[0] }}
+
+will render *this is one*.
+
+
 Available Store Variables
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 

extension/Classes/Core/Report/Report.php

@@ -712,6 +712,13 @@ class Report {
         }, ['is_safe' => ['html']]);
         $twig->addFilter($filter);
 
+        // Json decode Filter
+        // E.g.: {% set obj = '["this is one", "this is two"]' | json_decode%}
+        $filter = new \Twig\TwigFilter('json_decode', function ($string) {
+            return json_decode($string);
+        }, ['is_safe' => ['html']]);
+        $twig->addFilter($filter);
+
         // render Twig
         $contentTwig = $twig->render($twig_template, array(
             'context' => $resultAssoc,  // backward compatibility for MNF