# ColumnGroupDefinition

> _Since v0.2.9_

Declarative column group definition for GridConfig.columnGroups or
GroupingColumnsConfig.columnGroups.

#### Example

```ts
{ header: 'Personal Info', children: ['firstName', 'lastName'] }
```

## Properties

| Property | Type | Description |
| -------- | ---- | ----------- |
| `id?` | <code>string</code> | Unique group identifier. When omitted, auto-generated as a slug of header (e.g. `'Personal Info'` → `'personal-info'`). |
| `header` | <code>string</code> | Display label for the group header |
| `children` | <code>string[]</code> | Array of column field names belonging to this group |
| `renderer?` | <code>(params: <a href="/grid/plugins/grouping-columns/interfaces/groupheaderrenderparams/">GroupHeaderRenderParams</a>) =&gt; string &#124; void &#124; HTMLElement</code> | Custom renderer for this specific group's header cell. Takes precedence over GroupingColumnsConfig.groupHeaderRenderer. |