diff --git a/lib/filters.js b/lib/filters.js
index 45b04781..4b431937 100644
--- a/lib/filters.js
+++ b/lib/filters.js
@@ -132,7 +132,7 @@ exports.truncate = function(str, len, append){
  */
 
 exports.truncate_words = function(str, n){
-  var str = String(str)
+  let str = String(str)
     , words = str.split(/ +/);
   return words.slice(0, n).join(' ');
 };