# observe(_:options:changeHandler:) when the returned NSKeyValueObservation is deinited or invalidated, it will stop observing ``` @preconcurrency func observe(_ keyPath: KeyPath, options: NSKeyValueObservingOptions = [], changeHandler: @escaping @Sendable (Self, NSKeyValueObservedChange) -> Void) -> NSKeyValueObservation ``` --- 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)