diff --git a/lib/cartodb/middleware/cors.js b/lib/cartodb/middleware/cors.js
index ee924a90..65b7cf4f 100644
--- a/lib/cartodb/middleware/cors.js
+++ b/lib/cartodb/middleware/cors.js
@@ -1,6 +1,6 @@
-module.exports = function cors(extraHeaders) {
+module.exports = function cors (extraHeaders) {
     return function corsMiddleware (req, res, next) {
-        var baseHeaders = "X-Requested-With, X-Prototype-Version, X-CSRF-Token";
+        let baseHeaders = "X-Requested-With, X-Prototype-Version, X-CSRF-Token";
 
         if(extraHeaders) {
             baseHeaders += ", " + extraHeaders;