# transformPreference(_:_:) Applies a transformation to a preference value. ``` nonisolated func transformPreference(_ key: K.Type = K.self, _ callback: @escaping (inout K.Value) -> Void) -> some View where K : PreferenceKey ``` --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)