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Angular Data Grid: Row Grouping - Opening Groups

This section covers different ways to control how row groups are expanded and collapsed.

Opening Group Levels by Default

To open all groups down to a given group level use the groupDefaultExpanded grid option as shown below:

    /* other grid options ... */>

this.columnDefs = [
    { field: 'country', hide: true, rowGroup: true },
    { field: 'year', hide: true, rowGroup: true },
    { field: 'sport' },
    { field: 'total' }
// all 'country' row groups will be open by default
this.groupDefaultExpanded = 1;

In the snippet above, all country row groups will be expanded by default as groupDefaultExpanded = 1.

By default groupDefaultExpanded = 0 which means no groups are expanded by default. To expand all row groups set groupDefaultExpanded = -1.

The example below demonstrates the groupDefaultExpanded behaviour. Note the following:

  • There are two active row groups as the supplied country and year column definitions have rowGroup=true declared.
  • All country row groups are expanded by default as groupDefaultExpanded = 1.

Open Groups by Default

To have groups open by default, implement the grid callback isGroupOpenByDefault. This callback is invoked each time a group is created.

    /* other grid options ... */>

// expand when year is '2004' or when country is 'United States'
this.isGroupOpenByDefault = params => {
    return (params.field == 'year' && params.key == '2004') ||
        (params.field == 'country' && params.key == 'United States');

The params passed to the callback have the IsGroupOpenByDefaultParams interface:

In the example below, the country 'United States' and year '2004' are expanded by default. Note that year '2004' is expanded for all countries, not just 'United States'.

Expand / Collapse Groups via API

It is possible to expand and collapse all group rows using the expandAll() and collapseAll() grid API's as shown below:

// Expand all group rows

// Collapse all group rows

When more custom behaviour is required, obtain a reference to the rowNode and then call rowNode.setExpanded(boolean). For example, to expand a group with the name 'United States' would be done as follows:

this.gridApi.forEachNode(node => {
    if (node.key === 'United States') {

The following example demonstrates different ways to expand / collapse row groups via the grid API.

Next Up

Continue to the next section to learn about grouping with Complex Objects.