---
title: "applySnapshot(_:animatingDifferences:)"
framework: appkit
role: symbol
role_heading: Instance Method
path: "appkit/nscollectionviewdiffabledatasourcereference/applysnapshot(_:animatingdifferences:)"
---

# applySnapshot(_:animatingDifferences:)

Updates the UI to reflect the state of the data in the specified snapshot, optionally animating the UI changes.

## Declaration

```swift
func applySnapshot(_ snapshot: NSDiffableDataSourceSnapshotReference, animatingDifferences: Bool)
```

## Parameters

- `snapshot`: The snapshot reflecting the new state of the data in the collection view.
- `animatingDifferences`: If doc://com.apple.documentation/documentation/Swift/true, the diffable data source computes the difference between the collection view’s current state and the new state in the snapshot, which is an O(n) operation, where n is the number of items in the snapshot. The differences in the UI between the current state and new state are animated. If doc://com.apple.documentation/documentation/Swift/false, the collection view UI is set to the new state without any animations, with no additional overhead for computing a diff. Any ongoing item animations are interrupted and the collection view’s content is reloaded immediately.

## Discussion

Discussion It’s safe to call this method from a background queue, but you must do so consistently in your app. Always call this method exclusively from the main queue or from a background queue.

## See Also

### Updating Data

- [snapshot()](appkit/nscollectionviewdiffabledatasourcereference/snapshot().md)