# GroupRowModelItem

> _Since v0.1.1_

A group header row in the flattened render model.

Part of the RenderRow discriminated union (discriminant: `kind === 'group'`).
Group rows represent collapsed/expanded group headers in the virtualized row list.
They are produced by the grouping engine when `groupOn` categorizes rows into hierarchical groups.

#### Example

```typescript
function isGroup(row: RenderRow): row is GroupRowModelItem {
  return row.kind === 'group';
}
```

## Properties

| Property | Type | Description |
| -------- | ---- | ----------- |
| `kind` | <code>group</code> | Discriminant — always `'group'` for group header rows. |
| `key` | <code>string</code> | Composite group key (nested groups separated by `"||"`, e.g. `"Engineering||Frontend"`). |
| `value` | <code>any</code> | Display value for this group level (the last segment of the group path). |
| `depth` | <code>number</code> | Nesting depth (0 = top-level group). |
| `rows` | <code>any[]</code> | All data rows belonging to this group (including rows in nested sub-groups). |
| `expanded` | <code>boolean</code> | Whether this group is currently expanded (children visible). |