A message that an undo manager sends before undoing a change.
The undo manager posts this message after you call ``UndoManager/undo()`` or ``UndoManager/undoNestedGroup()``.
Because this is a "will"-style message, the undo manager sends the message before it performs the undo.
Observe this message with the identifier ``NotificationCenter/MessageIdentifier/willUndoChange``, or specify its type directly to the `addObserver(of:for:using:)` method.
The ``NotificationCenter/MainActorMessage/Subject`` of this message type is ``UndoManager``.
This message interoperates with the notification ``NSNotification/Name/NSUndoManagerWillUndoChange``.
The system notifies observers of the message when the ``NotificationCenter`` posts the notification.
Similarly, the system notifies observers of the notification when it posts the message.
Converts a posted notification into this main actor message type for any observers.
To implement this method in your own `MainActorMessage` conformance, retrieve values from the ``Notification``'s ``Notification/userInfo`` and set them as properties on the message.
- Parameter notification: The posted ``Notification``.
- Returns: The converted `MainActorMessage` or `nil` if conversion is not possible.
get · iOS 26.0+
name
TypeScript
static get nameValue(): Promise<NSNotification_Name>
Swift declaration
static var name: Notification.Name { get }
A optional name corresponding to this type, used to interoperate with notification posters and observers.
