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

JavaScript

var grid = $("#grid").kendoGrid({
    dataSource: {
        data: [
            {foo: 10, bar: "A"},
            {foo: 20, bar: "B"},
            {foo: 5, bar: "B"},
            {foo: 35, bar: "A"}
        ],
        schema: {
            model: {
                fields: {
                    foo: { type: "number" },
                    bar: { type: "string", defaultValue: "A" }
                }
            }                
        },
        group: {
         field: "bar", aggregates: [
            { field: "foo", aggregate: "sum" },
            { field: "foo", aggregate: "average"}
         ]
        },
        aggregate: [
            {field: "foo", aggregate: "sum"},
            {field: "foo", aggregate: "average"}
        ],
        change: function(e) {
            if(e.action && e.action === "add") {
                var model = e.items[0];
                model.set("bar", "B");
            }
        }
    },
    groupable: true,
    editable: true,
    toolbar: ["create", "save", "cancel"],
    columns: [
        {
            field: "foo",
            aggregates: ["sum", "average"],
            groupFooterTemplate: "Sum: #= sum # || Average: #= average #",
            footerTemplate: "Sum: #= sum # || Average: #= average #"
        },
        {
            field: "bar"    
        }
    ]   
}).data("kendoGrid");