JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://cdn.kendostatic.com/2012.2.710/js/kendo.all.min.js"></script>
<link rel="stylesheet" href="kendo.common.min.css">
<link rel="stylesheet" href="http://cdn.kendostatic.com/2012.2.710/styles/kendo.default.min.css">
<link rel="stylesheet" href="kendo.mobile.all.min.css">
<div id="grid"></div>

JavaScript

var arr = new kendo.data.ObservableArray([
    { Qty: 200, UnitPrice: 23 }, 
    { Qty: 300, UnitPrice: 22 }
]);
for (var i = 0; i < arr.length ; i++) {
      var arrn = arr[i];
      arrn.set("RAmount", function(){
      var n = this.get("Qty") * this.get("UnitPrice");
        return n
      });
    };


$("#grid").kendoGrid({
                        columns: [
                          {
                              field: "Qty",
                              title: "Qty"
                          },
                          {
                              field: "UnitPrice",
                              title: "UnitPrice"
                          },
                         {
                              title: "Amount",
                             template: "#: Qty * UnitPrice #"
                          },
                        ],
                        editable: true,
                        dataSource: arr,
                    });