docs: function generateFilter(obj) {
      var type = obj.field in DATE_FIELDS ? 'date' : typeof obj.value;
  
      if (Utils.isArray(obj.value)) {
          if (type === 'object') {
              type = typeof obj.value[0];
          }
          obj.value = obj.value.toString();
      }
  
      return [type, obj.field, obj.param, obj.value].join(' ');
  }