unable to create nested array about json-ditto HOT 3 CLOSED

{
  description: "category[0].coding[0].value"
}

{
  category: {
    "output": [],
    "innerDocument": "!",
    "mappings": {
      coding: {
        "output": [],
        "innerDocument": "!",
        "mappings": {
            "value": "description"
        }
      }
    }
  }
}

{
  "category": [
    {
      "coding": [
        {
          "value": "SARS-CoV-2 (COVID-19) IgM Ab [Units/volume] in Serum or Plasma by Immunoassay"
        }
      ]
    }
  ]
}