{
    "jsonSchema": {
        "title": "Null field example",
        "description": "A short form with a null field",
        "type": "object",
        "required": [
          "firstName"
        ],
        "properties": {
          "helpText": {
            "title": "A null field",
            "description": "Null fields like this are great for adding extra information",
            "type": "null"
          },
          "firstName": {
            "type": "string",
            "title": "A regular string field",
            "default": "Chuck"
          }
        }
      },
      "uiSchema": {
        "firstName": {
          "ui:autofocus": true,
          "ui:emptyValue": ""
        }
      },
      "formData": {
        "firstName": "Chuck"
      }
}