diff --git a/vendor/assets/javascripts/textAngular-sanitize.min.js b/vendor/assets/javascripts/textAngular-sanitize.min.js
index 215353cff0..77ab9f161d 100644
--- a/vendor/assets/javascripts/textAngular-sanitize.min.js
+++ b/vendor/assets/javascripts/textAngular-sanitize.min.js
@@ -3,6 +3,8 @@
  * (c) 2010-2014 Google, Inc. http://angularjs.org
  * License: MIT
  */
+if (!angular.lowercase) angular.lowercase = str => angular.isString(str) ? str.toLowerCase() : str;
+
 !function(a,b,c){"use strict";/**
  * @ngdoc module
  * @name ngSanitize