labels working with %kt

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>ZingSoft Demo</title>

  <script nonce="undefined" src="https://cdn.zingchart.com/zingchart.min.js"></script>
  <style>
    html,
    body {
      height: 100%;
      width: 100%;
      margin: 0;
      padding: 0;
    }

    #myChart {
      height: 100%;
      width: 100%;
      min-height: 150px;
    }

    .zc-ref {
      display: none;
    }
  </style>
</head>

<body>
  <div id="myChart"><a class="zc-ref" href="https://www.zingchart.com">Powered by ZingChart</a></div>
  <script>
    ZC.LICENSE = ["569d52cefae586f634c54f86dc99e6a9", "b55b025e438fa8a98e32482b5f768ff5"];
    window.customText = function(e) {
      console.log(e)
      return {
        text: e.scaletext + ' ' + e.value
      }
    }
    var myConfig = {
      "graphset": [{
        "title": {
          "text": "Heatmap Tooltip not working",
          "font-size": "12px"
        },
        "utc": true,
        "series": [{
          "values": [4182.09, 2553.66, 6254.63, 13619.54, 3589.93, 1258.33]
        }],
        "plot": {
          "errors": null,
          "tooltip": {
            text: '%kt'
          },
          "aspect": "brightness"
        },
        "type": "heatmap",
        "scaleX": {
          "tooltip": {
            "background-color": "white",
            "visible": true
          },
          "transform": {
            "type": "date",
            "text": "%d-%m-%Y\n%G:%i:%s"
          },
          "items-overlap": true,
          "item": {
            "offsetY": 0,
            "angle": 0,
            "text": null,
            "offsetX": 0,
            "maxChars": 3
          },
          "max-items": 200,
          "labels": [1447531826188, 1447531826244, 1447531827234, 1447531829683, 1447531829892, 1447531832628]
        }
      }]
    }

    zingchart.render({
      id: 'myChart',
      data: myConfig,
      height: '100%',
      width: '100%'
    });
  </script>
</body>

</html>

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>ZingSoft Demo</title>

  <script src="https://cdn.zingchart.com/zingchart.min.js"></script>
</head>

<body>
  <div id="myChart"><a class="zc-ref" href="https://www.zingchart.com">Powered by ZingChart</a></div>
</body>

</html>

html,
body {
  height: 100%;
  width: 100%;
  margin: 0;
  padding: 0;
}

#myChart {
  height: 100%;
  width: 100%;
  min-height: 150px;
}

.zc-ref {
  display: none;
}

window.customText = function(e) {
  console.log(e)
  return {
    text: e.scaletext + ' ' + e.value
  }
}
var myConfig = {
  "graphset": [{
    "title": {
      "text": "Heatmap Tooltip not working",
      "font-size": "12px"
    },
    "utc": true,
    "series": [{
      "values": [4182.09, 2553.66, 6254.63, 13619.54, 3589.93, 1258.33]
    }],
    "plot": {
      "errors": null,
      "tooltip": {
        text: '%kt'
      },
      "aspect": "brightness"
    },
    "type": "heatmap",
    "scaleX": {
      "tooltip": {
        "background-color": "white",
        "visible": true
      },
      "transform": {
        "type": "date",
        "text": "%d-%m-%Y\n%G:%i:%s"
      },
      "items-overlap": true,
      "item": {
        "offsetY": 0,
        "angle": 0,
        "text": null,
        "offsetX": 0,
        "maxChars": 3
      },
      "max-items": 200,
      "labels": [1447531826188, 1447531826244, 1447531827234, 1447531829683, 1447531829892, 1447531832628]
    }
  }]
}

zingchart.render({
  id: 'myChart',
  data: myConfig,
  height: '100%',
  width: '100%'
});