diff --git a/lib/url.js b/lib/url.js
index ab82cc2abbd8e8..d754fea3b25359 100644
--- a/lib/url.js
+++ b/lib/url.js
@@ -358,9 +358,7 @@ Url.prototype.parse = function parse(url, parseQueryString, slashesDenoteHost) {
     // First, make 100% sure that any "autoEscape" chars get
     // escaped, even if encodeURIComponent doesn't think they
     // need to be.
-    const result = autoEscapeStr(rest);
-    if (result !== undefined)
-      rest = result;
+    rest = autoEscapeStr(rest);
   }
 
   var questionIdx = -1;
@@ -441,8 +439,7 @@ function validateHostname(self, rest, hostname) {
 
 // Automatically escape all delimiters and unwise characters from RFC 2396.
 // Also escape single quotes in case of an XSS attack.
-// Return undefined if the string doesn't need escaping,
-// otherwise return the escaped string.
+// Return the escaped string.
 function autoEscapeStr(rest) {
   var escaped = '';
   var lastEscapedPos = 0;
@@ -538,12 +535,13 @@ function autoEscapeStr(rest) {
     }
   }
   if (lastEscapedPos === 0)  // Nothing has been escaped.
-    return;
+    return rest;
+
   // There are ordinary characters at the end.
   if (lastEscapedPos < rest.length)
-    return escaped + rest.slice(lastEscapedPos);
-  else  // The last character is escaped.
-    return escaped;
+    escaped += rest.slice(lastEscapedPos);
+
+  return escaped;
 }
 
 // format a parsed object into a url string