controlTextDidBeginEditing
controlTextDid... refers to a group of delegate methods in the macOS AppKit framework used to monitor edits in text controls. These methods are part of the NSControlTextEditingDelegate protocol and are designed to let a controller respond to changes in text fields, text views, and other controls that support editing. The most commonly used methods are controlTextDidBeginEditing:, controlTextDidChange:, and controlTextDidEndEditing:. Each method receives a Notification object whose object property is the NSControl that sent the event.
To use these methods, a class must conform to NSControlTextEditingDelegate and be assigned as the delegate
In addition to delegate methods, there are corresponding notifications that can be observed via NotificationCenter: NSControlTextDidBeginEditingNotification,
Notes: these delegates and notifications are specific to macOS AppKit. On iOS, similar functionality is achieved