diff --git a/public/js/lib/editor/index.js b/public/js/lib/editor/index.js
index 4bead7ef..830670e3 100644
--- a/public/js/lib/editor/index.js
+++ b/public/js/lib/editor/index.js
@@ -133,7 +133,7 @@ export default class Editor {
     this.config = config
 
     // define modes from mode mime
-    let ignoreOverlay = {
+    const ignoreOverlay = {
       token: function (stream, state) {
         stream.next()
         return null