docs: function stringifyQueryStr(obj) {
        if (!typeOf(obj, 'obj', 'arr')) return '';
        obj = JSON.parse(JSON.stringify(obj));
        var pairs = [];
        forIn(obj, function (key, value) {
          var encode = encodeURIComponent;
          pairs.push(encode(key) + '=' + encode(value));
        });
        return '?' + pairs.join('&');
      }