Do not attempt escape of non-string dependencies

Author: kgram

lib/url/escape.js

@@ -1,4 +1,7 @@
 module.exports = function escape(url) {
+    if (typeof url !== 'string') {
+        return url
+    }
     // If url is already wrapped in quotes, remove them
     if (/^['"].*['"]$/.test(url)) {
         url = url.slice(1, -1);