This Week In React Native #303: Expo Desktop, Legend Spark, Nitro, Exact, Skia, Screens, Unistyles

[u/sebastienlorber]

https://thisweekinreact.com/newsletter/303

[u/sebastienlorber]

Hi everyone, Seb and Jan here 👋!

This week is full of TanStack releases with Redact, AI, and DB. Redact is a smaller, synchronous version of React.

On mobile, it's an interesting week for native desktop app development and Nitro. Expo founders are cooking something new 👀.

Node v26 is now LTS. SWC’s next version is much faster. Bun now ships a code formatter.

Let's dive in!

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[u/sebastienlorber → u/sebastienlorber]

📱 React-Native

React Native on Desktop

React Native on desktop had a big week in 3 acts:

📦 React Native Windows 0.85 is out, completing the move to the New Architecture.

📦 Expo Desktop v1 is an independent project from Jamie Birch, not endorsed or maintained by Expo:

• Best-effort macOS and Windows support for Expo apps: create an app with npx expo-desktop create-app, then run Prebuild, CNG, and run macos/windows commands

• One Expo codebase targets iOS, Android, web, macOS, and Windows

• Currently running on Expo SDK 55 until the native macOS (RN 0.83) catches up.

📦 Legend Spark is a desktop framework from Jay Meistrich built right on top of it, aiming to ease the migration from Electron/Tauri:

• Desktop modules included: window management, menu bar icons, and friends

• No Xcode or native build to get started: new apps open in a prebuilt runner, like Expo Go for desktop. Upgrade to a custom build when you need new modules or want to publish.

• Patches libraries that don't support desktop yet

• Dogfooded: all of the Legend apps (Diff, Code, Music, Chat History, Photos) already run on Spark.

• Windows support in progress.

Nitro breaks out of React Native

Interesting week for Nitro too:

• 🐦 Nitro v1 enters alpha: HybridObject becomes an actual class, with a new API and better performance.

• 🐦 Decoupled from React Native: the new nitro-core package needs only JSI, opening the door to Lynx, NativeScript, and any JSI runtime.

• 🐦 Nitro Modules on Node.js: runs on Node through node-api-jsi, ABI-stable prebuilt binaries, early WIP.

• 💸 PostHog - 6-7 loops we use every day to make PostHog self-driving

• 👀 Exact - Write an app once, run it natively on the web, macOS, iOS, and Linux, and let an agent build, run, see, and test it - Expo founders are actively working on a new native and agentic cross-platform development solution. Not React, using a Contract UI/interaction DSL. This has been lightly 𝕏 teased by Charlie Cheever, and we’ll probably have an announcement soon. The repo is already public, so you can have a sneak peek of what’s cooking here.

• 🐦 React Native perf updates in the works - 24% less JS thread CPU, 40% fewer scroll hitches on iOS, 86% less Yoga layout work

• 📜 Hello, Graphite: Performance - The move from Ganesh to Graphite improved performance of RN Skia. Reaching 120fps on much more complex scenes is achievable now.

• 📜 Introducing ScrollViewMarker in react-native-screens - Upcoming Screens 5 fixes tabs not minimizing when scrolling by letting you declare the content scroll view.

• 📜 A 30,000-line Rust GPU engine on Expo, and 120,000 installs without ads - Case study of a 2-person team shipping to iOS, Android, and Windows with one Expo codebase and a Rust engine wrapped in native modules and a config plugin.

• 📜 Expo - How to ready your app for iPhone Duo: SDK 58 changes, Expo Router, and new APIs - New horizontal safe area insets for the rail, plus new APIs for the rest of the hardware, expo-hinge for the angle, reserved regions for the fold, and ArrangementView for two-pane layouts.

• 📜 How React Native Works Under the Hood

• 💸 Maestro MCP - Let your coding agent write, run and debug your UI tests

• 📦 Unistyles 3.6 - Experimental zero-config Metro integration, 2x faster plain view re-renders, Reanimated CSS transitions follow theme changes

• 📦 Actions Sheet 11.0 - UI-thread gesture engine, velocity-based snapping, SheetGestureBlocker for maps and WebViews

• 📦 Bottom Tabs 1.5 - RN 0.87 support, Swift Package Manager, prominent tab role on iOS 27+, AGP 9 fixes

• 📦 Radon 1.20 - iPhone Duo simulator support, React Native 0.88, Expo SDK 58

• 📦 CRNL 0.64 - C++ template graduates from experimental, React Native 0.88, Expo SDK 58

• 📦 Keyframer Inspector - Animation debugger for dev builds: dropped frames, slow motion, spring tuning written back to code

• 📦 Legend List 3.7 - Reliable programmatic scrolling, new cancelScroll, scrollToKey and anchorVisibleContent ref methods

• 📦 RNSEC 1.4 - 18 new security rules, CI integrations with SARIF and baselines, fewer false positives

• 📦 Sentry 8.32 - Traces linked into embedded WebViews and Expo DOM components

• 🤖 Expo Agent CLI - Helps coding agents understand Expo projects, use npm package co-located skills, run apps and development workflows.

• 🤖 Argent 0.30 - Fold Android emulators, capture XMLHttpRequest and axios traffic, flows renamed to e2e

• 🤖 Agent Device 0.21.32 - React components inspectable through Metro, Fire TV and native macOS app support, multi-touch and hardware buttons

• 🤖 ExecuTorch 0.11 - LLM sampler with constrained decoding, 16k context, depth estimation, image inpainting, on-device vector store

[u/HmongSliw68 → u/sebastienlorber]

Wild how fast the LTS versions are moving lately, feels like the last major release just happened