docs: function getAdminUrl() {
      var adminUrl = config.get('admin:url'),
          subDir = getSubdir();
  
      if (!adminUrl) {
          return;
      }
  
      if (!adminUrl.match(/\/$/)) {
          adminUrl += '/';
      }
  
      adminUrl = urlJoin(adminUrl, subDir, '/');
      adminUrl = deduplicateSubDir(adminUrl);
      return adminUrl;
  }