{
    "jsonSchema": {
        "title": "Files",
        "type": "object",
        "properties": {
          "file": {
            "type": "string",
            "format": "data-url",
            "title": "Single file"
          },
          "files": {
            "type": "array",
            "title": "Multiple files",
            "items": {
              "type": "string",
              "format": "data-url"
            }
          },
          "filesAccept": {
            "type": "string",
            "format": "data-url",
            "title": "Single File with Accept attribute"
          }
        }
      },
      "uiSchema": {
        "filesAccept": {
          "ui:options": {
            "accept": ".pdf"
          }
        }
      },
      "formData": {}
}