Ag-Grid Column分组标题排序

Question

这是参考：Link 我想在Grouped列中添加排序，即排序时（标题列应根据名称排序）。

另外，参考代码

var columnDefs = [
{headerName: "Country", field: "country", width: 120},
{headerName: "Sports Meta",
children: [
    {headerName: "Year", field: "year", width: 90},
    {headerName: "Sport", field: "sport", width: 110},
    {headerName: "Athlete", field: "athlete", width: 200}
]},
{headerName: "Sports Results",
children: [
  {headerName: "Gold", field: "gold", width: 100},
  {headerName: "Silver", field: "silver", width: 100},
  {headerName: "Bronze", field: "bronze", width: 100},
  {headerName: "Total", field: "total", width: 100},
  {headerName: "Age", field: "age", width: 90},
  {headerName: "Date", field: "date", width: 110}]}];
var gridOptions = {
columnDefs: columnDefs,
animateRows: true,
enableRangeSelection: true,
rowData: null,
enableSorting:true
};

var gridDiv = document.querySelector('#myGrid');
new agGrid.Grid(gridDiv, gridOptions);

// do http request to get our sample data - not using any framework to keep the example self contained.
// you will probably use a framework like JQuery, Angular or something else to do your HTTP calls.
var httpRequest = new XMLHttpRequest();
httpRequest.open('GET', 'https://raw.githubusercontent.com/ag-grid/ag-grid-docs/master/src/olympicWinners.json');
httpRequest.send();
httpRequest.onreadystatechange = function() {
    if (httpRequest.readyState === 4 && httpRequest.status === 200) {
        var httpResult = JSON.parse(httpRequest.responseText);
        gridOptions.api.setRowData(httpResult);
    }
};