Index: lib/url.js
===================================================================
--- a/lib/url.js
+++ b/lib/url.js
@@ -29,17 +29,17 @@
  * @param {?Frame}  frame
  * @param {URL}    [originUrl]
  * @return {string}
  */
 exports.extractHostFromFrame = (frame, originUrl) =>
 {
   for (; frame; frame = frame.parent)
   {
-    let hostname = frame.url.hostname;
+    let {hostname} = frame.url;
     if (hostname)
       return hostname;
   }
 
   return originUrl ? originUrl.hostname : "";
 };
 
 function isDomain(hostname)