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# itemWillExpandNotification

Posted before an item is expanded (after the user clicks the arrow but before the item is collapsed).

```
class let itemWillExpandNotification: NSNotification.Name
```

## Discussion

The notification object is the outline view that contains an item about to be expanded. The `userInfo` dictionary contains the following information:

|Key          |Value                                    |
|-------------|-----------------------------------------|
|`@"NSObject"`|The item that is to be expanded (an `id`)|

To observe this notification using Swift concurrency, use [`NSOutlineView.ItemWillExpandMessage`](/documentation/AppKit/NSOutlineView/ItemWillExpandMessage).

---

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