如何合并Ag-grid的单元？

// 假设你已经有一个Ag-grid实例
const gridOptions = {
    columnDefs: [
        { field: 'name', headerName: 'Name' },
        { field: 'age', headerName: 'Age' },
        { field: 'city', headerName: 'City' }
    ],
    rowData: [
        { name: 'John', age: 25, city: 'New York' },
        { name: 'Jane', age: 30, city: 'New York' },
        { name: 'Mike', age: 35, city: 'Los Angeles' }
    ],
    onGridReady: (params) => {
        params.api.sizeColumnsToFit();
        mergeCells(params);
    }
};

function mergeCells(params) {
    const gridApi = params.api;
    const gridColumnApi = params.columnApi;

    // 合并相同城市的单元格
    let lastRow = -1;
    let lastValue = null;
    gridColumnApi.getAllColumns().forEach((column) => {
        if (column.getColId() === 'city') {
            gridApi.forEachNodeAfterFilterAndSort((node, index) => {
                if (node.data.city === lastValue && index !== 0) {
                    node.setRowSpan(node.getRowSpan() + node.getDisplayedRowSpan());
                    const prevNode = gridApi.getRowNode(index - 1);
                    if (prevNode) {
                        prevNode.setRowSpan(prevNode.getRowSpan() - 1);
                    }
                } else {
                    lastValue = node.data.city;
                }
                lastRow = index;
            });
        }
    });
}

// 初始化Ag-grid
new agGrid.Grid(document.getElementById('myGrid'), gridOptions);