Refactor dispatcher project mr index path

app/assets/javascripts/dispatcher.js

@@ -152,6 +152,11 @@ import Activities from './activities';
           new UsersSelect();
           break;
         case 'projects:merge_requests:index':
+          import('./pages/projects/merge_requests/index')
+            .then(callDefault)
+            .catch(fail);
+          shortcut_handler = true;
+          break;
         case 'projects:issues:index':
           if (filteredSearchEnabled) {
             const filteredSearchManager = new gl.FilteredSearchManager(page === 'projects:issues:index' ? 'issues' : 'merge_requests');

app/assets/javascripts/pages/projects/merge_requests/index/index.js

+import IssuableIndex from '~/issuable_index';
+import ShortcutsNavigation from '~/shortcuts_navigation';
+import UsersSelect from '~/users_select';
+
+export default () => {
+  const filteredSearchEnabled = gl.FilteredSearchManager && document.querySelector('.filtered-search');
+
+  if (filteredSearchEnabled) {
+    const filteredSearchManager = new gl.FilteredSearchManager('merge_requests');
+    filteredSearchManager.setup();
+  }
+
+  new IssuableIndex('merge_request_'); // eslint-disable-line no-new
+  new ShortcutsNavigation(); // eslint-disable-line no-new
+  new UsersSelect(); // eslint-disable-line no-new
+};