diff --git a/src/es6/config.js b/src/es6/config.js
index 48a6b43..a2fe72d 100644
--- a/src/es6/config.js
+++ b/src/es6/config.js
@@ -12,7 +12,7 @@ const Config = {
      * @type string
      * @since 0.6.0
      */
-    "calendarType": 'persian',
+    'calendarType': 'persian',
 
 
     /**