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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 ...
}

When using the Group Rows Display Type there are no group columns to sort by, however row groups can still be ordered through the Default Group Order.

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.

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:

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 take precedence 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 Row Group Filtering.