code: function databaseUrl(root, databaseName) {
      if (!root.endsWith('/')) {
        root = root + '/';
      }
      return new url.URL(encodeURIComponent(databaseName), root).toString();
    }
docs: Combine a base URL and a database name, ensuring at least single slash
  between root and database name. This allows users to have Couch behind
  proxies that mount Couch's / endpoint at some other mount point.
  @param {string} root - root URL
  @param {string} databaseName - database name
  @return concatenated URL.
  
  @private