diff --git a/lib/main/build-site.js b/lib/main/build-site.js
index 11b9f9d00..a98beb9f1 100644
--- a/lib/main/build-site.js
+++ b/lib/main/build-site.js
@@ -137,7 +137,7 @@ function tidyHighlights($) {
       $element.attr('class', attr || null);
     });
     // Collapse nested highlights.
-    _.each(['comment', 'string'], function(cls) {
+    _.each(['comment', 'string'], cls => {
       $parent.find(`[class~="${ cls }"] > [class~="${ cls }"]`).each(function() {
         const $parent = $(this).parent();
         $parent.text($parent.text());