Snippet from the Oncology VIA form showing the `prior via result` question

Date of last VIA findings

{
  "label": "Prior VIA result:",
  "id": "priorviaresult",
  "type": "obs",
  "historicalExpression": "HD.getObject('prevEnc').getValue('f165c64a-9354-4145-9b06-4ee437630218')",
  "questionOptions": {
    "concept": "f165c64a-9354-4145-9b06-4ee437630218",
    "rendering": "select",
    "answers": [
      {
        "concept": "a896f3a6-1350-11df-a1f1-0026b9348838",
        "label": "Positive"
      },
      {
        "concept": "a896d2cc-1350-11df-a1f1-0026b9348838",
        "label": "Negative"
      }
    ],
    "showDate": "true",
    "shownDateOptions": {
      "validators": [
        {
          "type": "date"
        },
        {
          "type": "js_expression",
          "failsWhenExpression": "isEmpty(priorviaresult) && isEmpty(myValue)",
          "message": "Date result is required."
        }
      ],
      "hide": {
        "hideWhenExpression": "isEmpty(priorviaresult)"
      }
    }
  },
  "validators": [],
  "hide": {
    "hideWhenExpression": "priorviatest !== 'a899b35c-1350-11df-a1f1-0026b9348838'"
  }
}