diff --git a/lib/url.js b/lib/url.js
index f2a627fbbeaf9e..e75b829ddff0f2 100644
--- a/lib/url.js
+++ b/lib/url.js
@@ -634,7 +634,7 @@ Url.prototype.resolveObject = function(relative) {
   // strip single dots, resolve double dots to parent dir
   // if the path tries to go above the root, `up` ends up > 0
   var up = 0;
-  for (let i = srcPath.length; i >= 0; i--) {
+  for (var i = srcPath.length - 1; i >= 0; i--) {
     last = srcPath[i];
     if (last === '.') {
       spliceOne(srcPath, i);