ItemChildren

<script>
  var dataSource = new kendo.data.OrgChartDataSource({
    data: [
      { id: 1, name: "Jill", title: "Boss", expanded: true },
      { id: 2, name: "James", title: "Lead", expanded: true, parentId: 1 },
      { id: 3, name: "Joe", title: "Worker", expanded: true, parentId: 2 },
      { id: 4, name: "Jack", title: "Worker", expanded: true, parentId: 2 },
    ]
  });

  dataSource.read().then(function() {
    var children = dataSource.itemChildren(dataSource.data()[0]);
    console.log(children);
  });
</script>