Apply this patch https://gist.github.com/jiixyj/93277b471590c26cbc3d.

Author: susekaboss

common/content/util.js

@@ -827,7 +827,7 @@ const Util = Module("util", {
             return {
                 __proto__: ary,
                 __iterator__: function () this.iteritems(),
-                __noSuchMethod__: function (meth, args) {
+                mapImpl: function (meth, args) {
                     var res = util.Array[meth].apply(null, [this.__proto__].concat(args));
 
                     if (util.Array.isinstance(res))
@@ -836,7 +836,8 @@ const Util = Module("util", {
                 },
                 toString: function () this.__proto__.toString(),
                 concat: function () this.__proto__.concat.apply(this.__proto__, arguments),
-                map: function () this.__noSuchMethod__("map", Array.slice(arguments))
+                map: function () this.mapImpl("map", Array.slice(arguments)),
+                flatten: function () this.mapImpl("flatten", arguments)
             };
         }
     }, {

common/modules/template-tag.js

@@ -178,8 +178,9 @@ function templateXML(portion, ...args) // {{{
             break;
         case ATTR2:
             whiteSpace.lastIndex = offset;
-            whiteSpace.exec(str);
-            offset = whiteSpace.lastIndex;
+                if (whiteSpace.exec(str)) {
+                        offset = whiteSpace.lastIndex;
+                   }
             close = str[offset++];
             if (!close) {
                 if (i >= j) throw SyntaxError("attr right");

vimperator/content/config.js

@@ -5,7 +5,7 @@
 // This work is licensed for reuse under an MIT license. Details are
 // given in the License.txt file included with this file.
 
-const Config = Module("config", ConfigBase, {
+var Config = Module("config", ConfigBase, {
     init: function () {
         // TODO: delete me when minversion is greater than 34
         var {isSupport} = Cu.import("resource://liberator/CheckTemplate.jsm", {});