Unbound TreeGrid

import 'bootstrap.css';
import '@mescius/wijmo.styles/wijmo.css';
import './styles.css';
import * as wjGrid from '@mescius/wijmo.grid';
//
document.readyState === 'complete' ? init() : window.onload = init;
//
function init() {
    //
    // workers tree data (heterogeneous collection)
    var workers = [{
            name: 'Jack Smith',
            checks: [{
                    name: 'check1',
                    earnings: [
                        { name: 'hourly', hours: 30.0, rate: 15.0 },
                        { name: 'overtime', hours: 10.0, rate: 20.0 },
                        { name: 'bonus', hours: 5.0, rate: 30.0 }
                    ]
                }, {
                    name: 'check2',
                    earnings: [
                        { name: 'hourly', hours: 20.0, rate: 18.0 },
                        { name: 'overtime', hours: 20.0, rate: 24.0 }
                    ]
                }]
        }, {
            name: 'Jack Smith',
            checks: [{
                    name: 'check1',
                    earnings: [
                        { name: 'hourly', hours: 30.0, rate: 15.0 },
                        { name: 'overtime', hours: 10.0, rate: 20.0 },
                        { name: 'bonus', hours: 5.0, rate: 30.0 }
                    ]
                }, {
                    name: 'check2',
                    earnings: [
                        { name: 'hourly', hours: 20.0, rate: 18.0 },
                        { name: 'overtime', hours: 20.0, rate: 24.0 }
                    ]
                }]
        }, {
            name: 'Jane Smith',
            checks: [{
                    name: 'check1',
                    earnings: [
                        { name: 'hourly', hours: 30.0, rate: 15.0 },
                        { name: 'overtime', hours: 10.0, rate: 20.0 },
                        { name: 'bonus', hours: 5.0, rate: 30.0 }
                    ]
                }, {
                    name: 'check2',
                    earnings: [
                        { name: 'hourly', hours: 20.0, rate: 18.0 },
                        { name: 'overtime', hours: 20.0, rate: 24.0 }
                    ]
                }]
        }];
    //
    // unbound workers tree
    var uwt = new wjGrid.FlexGrid('#workersGrid', {
        headersVisibility: 'Column',
        selectionMode: 'Row',
        beginningEdit: function (s, e) {
            var value = e.panel.getCellData(e.row, e.col);
            if (value == null) {
                e.cancel = true; // can't edit!
            }
        }
    });
    //
    // add columns
    uwt.columns.push(new wjGrid.Column({ header: 'Name' }));
    uwt.columns.push(new wjGrid.Column({ header: 'Hours', dataType: 'Number', format: 'n2' }));
    uwt.columns.push(new wjGrid.Column({ header: 'Rate', dataType: 'Number', format: 'n2' }));
    //
    // add rows
    for (var w = 0; w < workers.length; w++) {
        //
        // add worker
        var worker = workers[w];
        var row = new wjGrid.GroupRow();
        row.dataItem = worker;
        row.isReadOnly = false;
        row.level = 0;
        uwt.rows.push(row);
        uwt.setCellData(row.index, 0, worker.name);
        for (var c = 0; c < worker.checks.length; c++) {
            //
            // add check
            var check = worker.checks[c];
            row = new wjGrid.GroupRow();
            row.dataItem = check;
            row.isReadOnly = false;
            row.level = 1;
            uwt.rows.push(row);
            uwt.setCellData(row.index, 0, check.name);
            for (var e = 0; e < check.earnings.length; e++) {
                //
                // add earning
                var earning = check.earnings[e];
                row = new wjGrid.GroupRow();
                row.dataItem = earning;
                row.isReadOnly = false;
                row.level = 2;
                uwt.rows.push(row);
                uwt.setCellData(row.index, 0, earning.name);
                uwt.setCellData(row.index, 1, earning.hours);
                uwt.setCellData(row.index, 2, earning.rate);
                //
            }
        }
    }
}