diff --git a/app/assets/javascripts/initializers/initializeCommentDate.js b/app/assets/javascripts/initializers/initializeCommentDate.js
index f7e201a10..34204945f 100644
--- a/app/assets/javascripts/initializers/initializeCommentDate.js
+++ b/app/assets/javascripts/initializers/initializeCommentDate.js
@@ -1,6 +1,8 @@
 /* Show comment date/time according to user's locale */
 /* global addLocalizedDateTimeToElementsTitles */
 
+'use strict';
+
 function initializeCommentDate() {
   var commentsDates = document.querySelectorAll('.comment-date time');