diff --git a/src/player.js b/src/player.js
index 90e565ca..9cd74b00 100644
--- a/src/player.js
+++ b/src/player.js
@@ -429,7 +429,7 @@ class ClapperPlayer extends GstClapper.Clapper
             return false;
 
         const now = this.position / Gst.SECOND;
-        let chapterTimes = Object.keys(chapters);
+        const chapterTimes = Object.keys(chapters);
         if(isPrevious)
             chapterTimes.reverse();