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JavaScript Data Grid: Row Grouping - Sorting Groups

This section provides details on how to configure and customise how row groups are sorted.

Enabling Group Sorting

When using Single Group Column or Multiple Group Columns, sorting can be enabled through the sortable column property as shown below:

const gridOptions = {
    defaultColDef: {
        // enable sorting across all columns - including Row Group Columns
        sortable: true,
    },
    autoGroupColumnDef: {
        // enabled sorting on Row Group Columns only 
        sortable: true,        
    },
    // also applies to the 'multipleColumns' display type 
    groupDisplayType: 'singleColumn',

    // other grid options ...
}

It is common to simply define defaultColDef.sortable = true across all columns, which includes row group columns. However, in cases where it is preferable to define sorting on the Row Group Columns directly, autoGroupColumnDef.sortable = true can be used.

Sorting is also enabled using the sortable column property with Custom Group Columns, as shown below:

const gridOptions = {
    columnDefs: [
        {   
            cellRenderer: 'agGroupCellRenderer',
            showRowGroup: true,
            // enabled sorting on this Row Group Column only 
            sortable: true,  
        },
    ],
    defaultColDef: {
        // enable sorting across all columns - including Row Group Columns
        sortable: true,
    },
    groupDisplayType: 'custom',

    // other grid options ...
}

The example below demonstrates how sorting is enabled with Multiple Group Columns. Note that sorting is enabled across all columns, including Row Group Columns, using: defaultColDef.sortable = true.

Mixed Group Sorting

By default, columns only apply sorting to their leaf level row data, as such to sort row groups you should apply the sort to the column on which the grouping has been applied.

This creates the side effect that groups can be sorted in multiple directions simultaneously, the group column reflects this by displaying the multi-sort icon when it does not match one or more of the provided columns sort direction.

const gridOptions = {
    columnDefs: [
        {
            field: 'year',
            rowGroup: true,
            sortable: true,
            sort: 'desc',
        },
        {
            field: 'handset',
            rowGroup: true,
            sortable: true,
            sort: 'asc',
        },
    ],

    // other grid options ...
}

In this snippet, sorting on the year or handset column will sort their respective row groups. As the year and handset column have different sorts applied to them, the group column displays the mixed sort icon.

The following example demonstrates mixed group sorting. Note the following:

  • Click the header of the group column to apply a sort, observe how it forces the year and handset columns sort to match.
  • Hold shift and click the header of the year column, observe how the sort direction is now different from the auto column, and the auto column now displays the mixed-sort icon.

Custom Group Sorting

By default, any sort comparator defined on a column that is used to group rows by will also be used by the Group Column. For example, consider the following column definition:

comparator
Function
Override the default sorting order by providing a custom sort comparator.
  • valueA, valueB are the values to compare.
  • nodeA, nodeB are the corresponding RowNodes. Useful if additional details are required by the sort.
  • isDescending - true if sort direction is desc. Not to be used for inverting the return value as the grid already applies asc or desc ordering.
  • Return:
  • 0 valueA is the same as valueB
  • > 0 Sort valueA after valueB
  • < 0 Sort valueA before valueB
  • comparator = (
        valueA: any,
        valueB: any,
        nodeA: RowNode<TData>,
        nodeB: RowNode<TData>,
        isDescending: boolean
    ) => number;
    const gridOptions = {
        columnDefs: [
            {
                field: 'month',
                rowGroup: true,
                comparator: (a, b) => {
                    const months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 
                                    'August', 'September','October', 'November', 'December'];
    
                    // sorts 'months' in chronological order
                    return months.indexOf(a) - months.indexOf(b);
                },
            },
        ],
    
        // other grid options ...
    }

    As rowGroup = true is defined on this column, the supplied comparator will be used to sort the month column and the Group Column.

    The following example demonstrates custom group sorting. Note the following:

    • The month column has a custom sort comparator supplied which sorts months in chronological order.
    • The 'Group' Column uses the comparator defined on the month column definition to sort the row groups.

    It is also possible to define a comparator that will be used across all group levels using; autoGroupColumnDef.comparator. This 'shared group comparator' will override over any comparators defined on the underlying columns.

    Maintain Group Order

    When sorting on non-group columns it may be desirable to maintain the existing group order. This behaviour can be enabled through the groupMaintainOrder grid option as shown below:

    const gridOptions = {
        columnDefs: [
            { field: 'assignee', rowGroup: true, hide: true },
            { field: 'priority', rowGroup: true, hide: true },        
            { field: 'task' },      
        ],
        groupDisplayType: 'multipleColumns',
        // preserves current group order when sorting on non-group columns
        groupMaintainOrder: true,
    
        // other grid options ...
    }

    Note that Group Order is not the same as sorting. Maintaining group order will not preserve active group sorts, just the current order of the groups. However, when sorting on group columns the group order will be changed based on the sort.

    The following example demonstrates how groupMaintainOrder works. Note the following:

    • groupMaintainOrder = true is defined on the grid options supplied to the grid.
    • Clicking on the 'Task' column header only sorts the tasks without reordering the groups.
    • Sorting on the 'Assignee' or 'Priority' group column headers will reorder the groups.

    Next Up

    Continue to the next section to learn about Filtering Groups.