Adding support for filters

Author: atlza

README.md

@@ -82,14 +82,15 @@ $twig = $this->twig->getTwig();
 
 Some helpers are added the functionality of auto-escaping for security.
 
-### Adding Your Functions
+### Adding Your Functions & filters
 
-You can add your functions with configuration:
+You can add your functions and filters with configuration:
 
 ~~~php
 $config = [
 	'functions' => ['my_helper'],
 	'functions_safe' => ['my_safe_helper'],
+	'filters' => ['my_filter'],
 ];
 $this->twig = new \Kenjis\CI4Twig\Twig($config);
 ~~~

src/CI4Twig/Twig.php

@@ -40,6 +40,11 @@ class Twig
         'site_url',
     ];
 
+    /**
+     * @var array Filters to add to Twig
+     */
+    private $filters = [];
+
     /**
      * @var array Functions with `is_safe` option
      *
@@ -87,6 +92,14 @@ public function __construct($params = [])
             unset($params['functions_safe']);
         }
 
+        if (isset($params['filters'])) {
+            $this->filters =
+                array_unique(
+                    array_merge($this->filters, $params['filters'])
+                );
+            unset($params['filters']);
+        }
+
         if (isset($params['paths'])) {
             $this->paths = $params['paths'];
             unset($params['paths']);
@@ -179,12 +192,29 @@ public function render($view, $params = []): string
         // We call addFunctions() here, because we must call addFunctions()
         // after loading CodeIgniter functions in a controller.
         $this->addFunctions();
+        $this->addFilters();
 
         $view = $view . '.twig';
 
         return $this->twig->render($view, $params);
     }
 
+    protected function addFilters()
+    {
+        if( !empty($this->filters) ){
+            foreach ($this->filters as $filter) {
+                if (function_exists($filter)) {
+                    $this->twig->addFilter(
+                        new \Twig\TwigFilter(
+                            $filter,
+                            $filter
+                        )
+                    );
+                }
+            }
+        }
+    }
+
     protected function addFunctions()
     {
         // Runs only once