Empty values in JSON

Data source

HTML

<link rel="stylesheet" href="https://s3.amazonaws.com/flexmonster/2.3/demo.css">
<script src="https://cdn.flexmonster.com/flexmonster.js"></script>

<div id="pivot-container"></div>

JavaScript

var pivot = new Flexmonster({
	container: "pivot-container",
  componentFolder: "https://cdn.flexmonster.com/",
  width: "100%",
  height: 430,
  toolbar: true,
  report: {
    dataSource: {
      dataSourceType: "json",
      data: getData()
    },
    slice: {
      rows: [{uniqueName: "Color"}],
      columns: [{uniqueName: "[Measures]"}],
      measures: [{uniqueName: "Price"},
      {uniqueName: "Quantity"},
      {caption:'test', uniqueName: "test", 
      formula: "(sum('Price')/2)"}]
    }
  }
});

function getData() {
  return [{
    "Color": "green",
    "M": "September",
    "W": "Wed",
    "country": "Canada",
    "state": "Ontario",
    "city": "Toronto",
    "Price": 174,
    "Quantity": 22
  }, {
    "Color": "red",
    "M": "March",
    "W": "Mon",
    "Time": "1000",
    "country": "USA",
    "state": "California",
    "city": "Los Angeles",
    "Price": "",
    "Quantity": 19
  }];
}