如何在AgGrid中获取组数

<!-- AgGrid样式 -->
<link rel="stylesheet" href="https://unpkg.com/ag-grid-community/dist/styles/ag-grid.css" />
<link rel="stylesheet" href="https://unpkg.com/ag-grid-community/dist/styles/ag-theme-alpine.css" />

<!-- AgGrid脚本 -->
<script src="https://unpkg.com/ag-grid-community/dist/ag-grid-community.min.noStyle.js"></script>

<div id="myGrid" style="width: 100%; height: 500px;"></div>

var columnDefs = [
  { headerName: "姓名", field: "name" },
  { headerName: "年龄", field: "age" },
  { headerName: "组数", field: "group" }
];

var rowData = [
  { name: "张三", age: 25, group: "A组" },
  { name: "李四", age: 30, group: "B组" },
  { name: "王五", age: 28, group: "A组" },
  { name: "赵六", age: 35, group: "C组" }
];

// 初始化AgGrid
var gridOptions = {
  columnDefs: columnDefs,
  rowData: rowData
};

// 获取组数
function getGroupCount() {
  var api = gridOptions.api;
  var model = api.getModel();
  var groups = model.getRowCount();

  console.log("组数: " + groups);
}

// 监听Grid Ready事件
document.addEventListener("DOMContentLoaded", function() {
  var gridDiv = document.querySelector("#myGrid");
  new agGrid.Grid(gridDiv, gridOptions);

  // 调用获取组数的函数
  getGroupCount();
});