Nil Coalescing

SwiftFairy brings our Swift and SwiftUI expertise to your coding agent, running static analysis on your Mac over MCP and returning targeted guidance for each flagged issue: nilcoalescing.com/blog/Introdu... #iOSDev #SwiftUI #SwiftLang

SwiftUI’s new onHingeChange() modifier in iOS 27.1 reports the hinge angle as iPhone Duo folds and unfolds, which is great for interactions and visual effects that respond to the folding motion itself. In my new post, I show how we can use it to drive an animation: nilcoalescing.com/blog/Driving...

Compare the effects of stored inputs, state, bindings, environment values and observable models on SwiftUI view updates through input comparison, access tracking and subscription behavior: nilcoalescing.com/blog/SwiftUI... #iOSDev #SwiftUI

Only just noticed that Breve is featured in Great Apps Updated for iOS 27 on the App Store in New Zealand 😅 apps.apple.com/nz/app/breve...

Meet Whio, an EPUB and PDF reader for technical books on iPhone and iPad, and explore its reading features, accessibility options, and the story behind its development: nilcoalescing.com/blog/Introdu... #iOSDev #IndieDev #ebooks

When building iOS apps with SwiftUI, we have found that providing in-the-loop feedback from SwiftFairy to agents, rather than front-loading our agents with a huge skill library, helps keep context small and ensures better attention to issues, resulting in more performant code. #SwiftUI #AI #iOSDev

Read the fold's position from SwiftUI's reserved regions on iPhone Duo and lay out grids around it, keeping the number of columns stable as the device folds and unfolds: nilcoalescing.com/blog/Positio... #iOSDev #SwiftUI

A little preview of Breve on iPhone Duo: apps.apple.com/app/apple-st...

I wrote a post sharing a bit more about Whio, my new ebook reader, and why I decided to build it after years of writing technical books. I also talk about some of the features, accessibility work, and how iPhone Duo inspired the app: nilcoalescing.com/blog/Introdu... #iOSDev #IndieDev #ebooks

Prevent full-width pages in SwiftUI scroll views from drifting out of alignment by removing extra spacing between pages when using paging behavior: nilcoalescing.com/blog/FixMisa... #iOSDev #SwiftUI

In testing agents, even after reading Apple’s docs, they repeatedly misused the new ArrangementView APIs, so we added a few more focused rules to explicitly detect these. SwiftFairy will automatically update SwiftUI Layout & Resizability to 2026.10.3 tools.nilcoalescing.com/swiftfairy/s... #iOSDev

SwiftUI layout containers such as stacks and grids don’t avoid the fold on iPhone Duo automatically, but we can use the reserved regions APIs to account for it. In my new post, I show how we can lay out items on either side of the fold in a lazy grid: nilcoalescing.com/blog/Positio... #iOSDev

With .paging scroll behavior in SwiftUI, the default spacing of an HStack or LazyHStack can make full-width pages drift further out of alignment with each swipe. Setting the stack spacing to zero keeps every page lined up. I wrote a short post about it: nilcoalescing.com/blog/FixMisa... #iOSDev

I've built an ebook reader for technical EPUBs and PDFs, and it's now available on the App Store! Whio makes reading technical books more enjoyable, with syntax highlighting, preserved code indentation, and PDF text reflow for comfortable reading on screens of any size. nilcoalescing.com/apps/whio

AI coding agents still struggle with adaptive SwiftUI layouts, and iPhone Duo adds more challenges with different poses, orientations, and window sizes. Our new SwiftFairy Scroll helps agents avoid layout mistakes and build more flexible interfaces: tools.nilcoalescing.com/swiftfairy/s... #iOSDev

ArrangementView lets SwiftUI place two related views side by side, stacked or layered depending on the available space and the fold on iPhone Duo, with split and overlay styles to configure the result: nilcoalescing.com/blog/Arrange... #iOSDev #SwiftUI

So nice to hear my blog post about the new SwiftUI ArrangementView API mentioned during the latest Apple iPhone Duo group lab 😃 www.youtube.com/live/kmf3gkQ...

ArrangementView is a new SwiftUI API in iOS 27.1 that takes some time to get your head around, so I wrote a post exploring it on iPhone Duo, with lots of examples of how split and overlay layouts adapt as the device folds: nilcoalescing.com/blog/Arrange... #iOSDev #SwiftUI

Just released SwiftUI Layout & Resizability, a new Scroll for SwiftFairy, our Mac app that gives coding agents in-the-loop code review while optimizing token usage. If you already have any other Scroll, you can save when picking this one up. tools.nilcoalescing.com/swiftfairy/p... #iOSDev #MCP

We’ve just released a new Scroll for SwiftFairy that focuses on SwiftUI layout and resizability! It covers over 100 issues your AI coding agent can check for to make sure your app is ready for iPhone Duo and resizable windows in general: tools.nilcoalescing.com/swiftfairy/s... #iOSDev #SwiftUI

Configure a SwiftUI app to schedule and handle a background fetch task using the Background Tasks framework and the backgroundTask(_:action:) SwiftUI modifier: nilcoalescing.com/blog/Schedul... #iOSDev #SwiftUI

Customize the appearance of the macOS window toolbar in SwiftUI using scene and view modifiers to control its layout, title visibility, and background: nilcoalescing.com/blog/AGuideT... #macOSDev #SwiftUI

Review automatic SwiftUI sheet adaptations on iPhone Duo and configure sheet placement and toolbar arrangement to suit the content being presented: nilcoalescing.com/blog/Present... #iOSDev #SwiftUI

Use SwiftUI transaction values to identify updates made by wrapped UITextView and NSTextView editors, preventing the same values from being applied again when SwiftUI sends them back: nilcoalescing.com/blog/Trackin... #iOSDev #macOSDev #SwiftUI

If your app presents sheets, it's worth checking how they look on iPhone Duo. My new post covers SwiftUI's automatic adaptations, sheet placement, toolbar customization, and a workaround for a beta layout issue: nilcoalescing.com/blog/Present... #iOSDev #SwiftUI

Just pushed an update to SwiftFairy 🧚, our native macOS MCP server that reviews your agent’s code locally for correctness, performance, and maintainability. Large reviews are faster in 2026.10.1: agents can now send file paths instead of source code. tools.nilcoalescing.com/swiftfairy/ #iOSDev #AI

Dive into how static and dynamic dispatch work in Swift, how they affect performance, and how to control method resolution to write faster, more efficient code: nilcoalescing.com/blog/MethodD... #SwiftLang

The September issue of the Nil Coalescing newsletter is out 📬 It includes an introduction to SwiftFairy, our Mac app that helps coding agents review Swift and SwiftUI code, plus iOSDevUK highlights and this month's articles: nilcoalescing.com/newsletter/2...

SwiftFairy 2026.9.2 is out. Large audits now take seconds, not minutes, and use far less of your agent's context. The video shows a pattern I've noticed agents often write: Binding(get:set:) in a view body, and the labeled subscript SwiftFairy steers them to. tools.nilcoalescing.com/swiftfairy

Most heatmaps use rectangular grids, but with Swift Charts we can use PointPlots to arrange cells with alternative shapes. In my new post, we explore hexagonal cells for spatial data. nilcoalescing.com/blog/Visuali... #iOSDev #SwiftUI #SwiftLang

If, like me, you were wondering how to show the slider to control the hinge angle in the iPhone Duo simulator in Xcode 27.1, we need to hold the Option key to reveal it 🙂

Besides reviewing code, I've been using SwiftFairy while building new features. Asking the agent to check SwiftFairy before working on Swift or SwiftUI code allows it to pull in relevant examples for the APIs it's about to use. tools.nilcoalescing.com/swiftfairy/h... #iOSDev #SwiftUI #SwiftLang

SwiftFairy 2026.9.1 is out! 🧚 SDK and project lookups are more reliable, and the complexity limits are much higher, so those huge views we all have get a proper review rather than just "too complex, please break it up". Release notes: tools.nilcoalescing.com/swiftfairy/r... #iOSDev #SwiftUI

We've had many questions about how SwiftFairy, our new code review app for Swift and SwiftUI, compares to skills and fits into an agent workflow. I've written a post explaining how agents work with it and why it's more reliable: nilcoalescing.com/blog/Introdu... #SwiftUI #AICoding #iOSDev

Control how SwiftUI presents toolbar items and tabs on iPhone Duo with the new iOS 27.1 APIs, from arranging custom labels to prioritizing actions when space is limited: nilcoalescing.com/blog/Configu... #iOSDev #SwiftUI

I’ve been trying to turn our articles and books into skills, but agents struggle to navigate them and forget rules they just read. So we ended up building SwiftFairy to detect issues and attach guidance inline, so agents no longer need to recall it all. tools.nilcoalescing.com/swiftfairy/ #iOSDev

We've released a new developer tool! SwiftFairy is a native Mac app that reviews your AI agent's Swift and SwiftUI code locally on device and provides focused guidance and improvement suggestions. Excited for you to try it out! tools.nilcoalescing.com/swiftfairy #iOSDev #SwiftLang #SwiftUI

Use the AttributedString API to build a reusable Text initializer in SwiftUI that applies a distinct font to the unit component of a formatted measurement: nilcoalescing.com/blog/Styling... #iOSDev #SwiftUI

Sometimes we want a gradient to span the whole plot rather than restart within each mark. In Swift Charts, alignsMarkStylesWithPlotArea(true) gives marks a shared gradient alignment. Learn more in our book, Swift Charts Beyond the Basics: books.nilcoalescing.com/swift-charts... #iOSDev #SwiftUI

"The SwiftUI Way" has been updated with expanded guidance on SwiftUI data flow, view updates, and performance, including changes introduced in Xcode 27: nilcoalescing.com/blog/TheSwif... #iOSDev #SwiftUI

Build SwiftUI views that update periodically or continuously, without relying on explicit state changes, to create dynamic interfaces and visual effects: nilcoalescing.com/blog/Timelin... #iOSDev #SwiftUI

Reorder items within and between custom SwiftUI containers, and build selection-aware multi-item drag and drop interactions with the new APIs in iOS 27: nilcoalescing.com/blog/NewSwif... #iOSDev #SwiftUI

I've started looking into the new SwiftUI APIs for iPhone Duo in Xcode 27.1 and wrote a post on configuring toolbars, adapting custom labels, and prioritizing toolbar actions or tabs when space is limited: nilcoalescing.com/blog/Configu... #iOSDev #SwiftUI

Learn how to enable SwiftUI's ForEach slow-path diagnostic in Xcode, interpret warnings about variable view counts, and address the reported patterns in List and lazy stacks: nilcoalescing.com/blog/Diagnos... #iOSDev #SwiftUI

SwiftUI now includes CrossFadeNavigationTransition, a built-in cross-fade navigation transition, and AnyNavigationTransition, a type-erased wrapper that allows transitions to be selected dynamically at runtime: nilcoalescing.com/blog/SwiftUI... #iOSDev #SwiftUI

iOS 27 gives AsyncImage more control over remote image loading with URLRequest support for custom headers, cache policies, and timeouts, plus the ability to provide a custom URLSession across a SwiftUI view hierarchy: nilcoalescing.com/blog/AsyncIm... #iOSDev #SwiftUI

Just got back from our trip to Wales for iOSDevUK! It was lovely to catch up with everyone and learn from so many great talks. I also really enjoyed running my SwiftUI workshop and seeing everyone excited to dig deeper into SwiftUI, with lots of thoughtful questions and discussions 👩‍💻

Explore every SwiftUI blend mode through focused visuals and practical use cases, and learn how to control which views participate in each operation: nilcoalescing.com/blog/BlendMo... #iOSDev #SwiftUI

To diagnose performance issues caused by the structure of ForEach content in SwiftUI's List and lazy stacks, we can enable slow-path logging in Xcode. My new post shows how to set it up, interpret the diagnostic messages, and address the reported issues: nilcoalescing.com/blog/Diagnos... #iOSDev

Control which SwiftUI toolbar actions stay visible, move commands into overflow, pin an important item and configure navigation bar minimization with the new iOS 27 APIs: nilcoalescing.com/blog/Adaptiv... #iOSDev #SwiftUI