Happier, more flexible NSTextStorage

What's New


  • Concurrency support

Build Status License Platforms


TextStory is a small set of classes and protocols for easier work with NSTextStorage and associated systems. iOS and macOS are supported.


Swift Package Manager:

dependencies: [
    .package(url: "https://github.com/ChimeHQ/TextStory")


A minimal NSTextStorage subclass that provides hooks for much more powerful delegate behavior. Great for separating logic/behavior from your storage object. Because it is built to wrap another NSTextStorage instance, it is more easily composable.

Unfortunately, to date I've not been able to figure out a way to build this class in Swift. If you have experience working with NSTextStorage and Swift/ObjC automatic NSString/String bridging, I'd love to hear from you.

- (void)textStorage:(TSYTextStorage *)textStorage willReplaceCharactersInRange:(NSRange)range withString:(NSString *)string;
- (void)textStorage:(TSYTextStorage *)textStorage didReplaceCharactersInRange:(NSRange)range withString:(NSString *)string;
- (void)textStorageProcessEditingComplete:(TSYTextStorage *)textStorage;

// available for macOS only
- (NSRange)textStorage:(TSYTextStorage *)textStorage doubleClickRangeForLocation:(NSUInteger)location;
- (NSUInteger)textStorage:(TSYTextStorage *)textStorage nextWordIndexFromLocation:(NSUInteger)location direction:(BOOL)forward;


An NSTextStorage subclass that maintains a history of text changes with low memory and performance overhead. This class makes it possible to decouple text change processing from them Cocoa text display system, making them asynchronous with respect to each other. Very useful for keeping your UI fast and responsive even if the processing of changes can be slow.

// interact with the buffered view of text
func bufferedSubstring(from range: NSRange) -> String
var bufferedLength: Int

// commit one change in the queue, allowing precise control over how the buffered view changes
func applyNextChange()


A simple protocol that abstracts string storage. This is very useful for standardizing behavior across NSTextStorage and other objects you may use for text manipulation. Particularly handy for testing and decoupling systems from Apple's classes behaviors/APIs.

In order to maintain flexiblity and match NSTextStorage, TextStoring is not actor-isolated.


It isn't possible to make NSTextView/UITextView conform to TextStoring, because they are MainActor-isolated classes. This adapter exists to help use a view with TextStoring.


Standard interface for systems that need to observe and react to changes in a TextStoring instance.


A concrete TextStoringMonitor class that implements progressive, on-demand access to a wrapped TextStoringMonitor. This makes it easy to add lazy semantics on top of an existing TextStoringMonitor, which can be very helpful for handling large documents.


An easy way to group together a collection of TextStoringMonitor instances and tread them as a single unit.


This class can accept and route TSYTextStorage delegate callbacks to multiple TextStoringMonitor instances. This is super handy for faning-out these calls.

Suggestions or Feedback

We'd love to hear from you! Get in touch via an issue or pull request.

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.


  • Swift Tools 5.5.0
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Last updated: Sat Nov 25 2023 05:32:39 GMT-1000 (Hawaii-Aleutian Standard Time)