Foundation updates

Overview

Browse notable changes in Foundation.

June 2025

• Post and observe concurrency-safe notifications with new features in NotificationCenter that support Swift-friendly “message” types. Use NotificationCenter.MainActorMessage for notification messages bound to the MainActor and NotificationCenter.AsyncMessage for messages that are Sendable. Add an observer to one of these notification message types with the various addObserver(of:for:using:) methods in NotificationCenter. Many standard notifications in Foundation, UIKit, and AppKit now offer a message-based API, associating the message with an existing Notification.Name. You can also associate a message with a new name for Swift-only notifications.

• Simplify usage of UndoManager on the main actor, now that the undo manager is marked with @MainActor. The undo manager also adds a setActionName(_:) method that takes a LocalizedStringResource. Use this with the App Intents framework, which introduces a new UndoableIntent.

• Access your app, app extension, or framework’s bundle with the #bundle macro. Using the macro is more performant and convenient than using .self or a bundle identifier, particularly when loading localized strings with initializers that take a bundle: parameter. The macro back-deploys, so you can use it with projects whose deployment targets specify earlier versions of the operating system.

• Get UTF-8 and UTF-16 views of an AttributedString with the utf8 and utf16 methods of AttributedStringProtocol.

• Access multiple ranges of an AttributedString with the new DiscontiguousAttributedSubstring type. You can get this type from an attributed string with either a RangeSet of indices, or with the new AttributedTextSelection type.

June 2024

Predicates

• Use Regex regular expressions in predicates to perform pattern matching. You can use either the Swift regex domain specific language or traditional regex literals.

• Use the new #Expression macro when you want behavior similar to #Predicate but you need to return a type other than Bool.

• Create compound predicates by writing a Predicate that evaluates another Predicate.

Calendars

• Perform Calendar searches by calling dates(byMatching:startingAt:in:matchingPolicy:repeatedTimePolicy:direction:) with DateComponent values specifying what to search for, and receiving a Sequence of matching dates. You can also repeatedly add DateComponent values to a date with dates(byAdding:startingAt:in:wrappingComponents:) and receive a sequence. To add Calendar.Component values instead, use dates(byAdding:value:startingAt:in:wrappingComponents:).

Format styles

• Use the DiscreteFormatStyle protocol to format values that constantly change, but don’t necessarily change the formatted output on every update, such as time displays that truncate the seconds field. The following format style types conform to the new protocol: Duration.UnitsFormatStyle, Duration.TimeFormatStyle, Date.FormatStyle, Date.FormatStyle.Attributed, Date.VerbatimFormatStyle, Date.VerbatimFormatStyle.Attributed, Date.ISO8601FormatStyle, Duration.UnitsFormatStyle.Attributed, and Duration.TimeFormatStyle.Attributed.

• Set new configuration options on FormatStyle to omit specific symbols from the output and suppress grouping of large time values (for example, in order to produce 10000:00 rather than 10,000:00).

• Use the notation modifier on currency format styles to specify a notation such as compactName, similar to how notation already works on numeric format styles.

Undo manager

• Provide custom information for undo actions by setting user info on UndoManager. The info can include things like a timestamp of the action’s creation or an icon that complements the action name.

• Reveal the size of an undo manager’s current undo or redo stack with the properties undoCount and redoCount.

Key-Value observing

• Add a collection of shared observers to Observable objects that you can then add to multiple instance of the observable.

• Observables now use ARC-style weak references to their observers, preventing crashes when observers deallocate without properly removing themselves.

Collections

• You can initialize an IndexSet from a Swift RangeSet, and vice versa.

See Also

Technology and frameworks

• Accelerate updates
• Accessibility updates
• ActivityKit updates
• AdAttributionKit Updates
• App Clips updates
• App Intents updates
• AppKit updates
• Apple Intelligence updates
• AppleMapsServerAPI Updates
• Apple Pencil updates
• ARKit updates
• Audio Toolbox updates
• AuthenticationServices updates
• AVFAudio updates
• AVFoundation updates