Default sort in template with json source

[orlenkoda5 (Данила Орленко)]

@RabBit_BR

POST _render/template
{
  "source": """{ 
          "sort":  {{#sort_default}}
                     {{#toJson}}my_sort{{/toJson}} },
                   {{/sort_default}}
                      {"default_sort": { "order": "desc"}} 
      }""",
  "params": {
    "sort_default": false,
    "my_sort": {
      "lastPriceDate": {
        "order": "desc"
      }
    }
  }
}

Thank you