2026-06-29 · #34
React Native Weekly #34 Reanimated 4.5 CSS Pseudo-Selectors, react-native-quick-crypto Speed, Native Modules Expo SDK 56 and more
Native Modules Up to 2.3× Faster in Expo SDK 56#
Swift now communicates directly with JSI, eliminating the Objective-C++ layer from the call path. Native module calls on Apple platforms are 1.6–2.3× faster, reaching performance on par with or better than Turbo Modules.
A detailed write-up by @tsapeta is also available.
𝝠 Expo native modules are 1.6 to 2.3x faster on Apple platforms in SDK 56. Swift talks to JSI directly. The Objective-C++ layer in the call path is gone, so calls lower straight to C++, matching or beating Turbo Modules. Deep dive from @tsapeta: try.expo.dev/jsi-twitter
Talking to JSI in Swift: what changed in SDK 56In SDK 56, Expo's native modules call JSI directly on Apple platforms. The Objective-C++ layer is gone, and calls are 1.6–2.3x faster. Expo Blog
Hermes New Stable Release 260318099.0.0#
A large batch of features landed all at once: Iterator Helpers, Object.groupBy, Set operations, Promise.withResolvers, a built-in TextDecoder, TypeScript type stripping, and more. The release also includes significant JSON performance improvements and spec-compliance fixes.
New Hermes Release 260318099.0.0 The new stable release brings features like Iterator Helpers, Object.groupBy, Set operations, Promise.withResolvers, built-in TextDecoder, TypeScript type stripping, significantly faster JSON performance, and many spec compliance fixes.
Reanimated 4.5 Introduces CSS Pseudo-Selectors#
CSS pseudo-selectors like :hover, :active, and :focus are now available in React Native.
They use native backends on both iOS and Android, and can be applied to CSS animations using the exact same syntax as in the browser.
Reanimated 4.5 brings pseudo-selectors to React Native! 🐎 You can now use :hover, :active, and :focus in your CSS animations the same way you would in a browser, with native backends on iOS and Android. Check out the demo below and more features in this release ⬇️
LegendList 3.2.0’s experimental_adaptiveRender#
The experimental_adaptiveRender prop added in LegendList 3.2.0 reduces blanking by switching to a lightweight component when scroll speed exceeds a threshold.
It can skip image loading, gesture detector setup, modal initialization, and more — lowering rendering overhead during fast scrolls.
LegendList 3.2.0 has a new experimental_adaptiveRender prop, which can improve blanking if you have heavy components. You can render light components when scrolling over a velocity threshold. So you could skip images, gesture detectors, modal setup, etc... Right has it enabled.
react-native-quick-crypto Is Up to 7,500× Faster Than JS Polyfills#
Margelo showcased react-native-quick-crypto, demonstrating that it can be up to 7,500× faster than JavaScript-based polyfills.
Did you know that 𝚛𝚎𝚊𝚌𝚝-𝚗𝚊𝚝𝚒𝚟𝚎-𝚚𝚞𝚒𝚌𝚔-𝚌𝚛𝚢𝚙𝚝𝚘 is up to 7,500× faster than JS based polyfills? Not seven point five times, 𝘀𝗲𝘃𝗲𝗻-𝘁𝗵𝗼𝘂𝘀𝗮𝗻𝗱-𝗳𝗶𝘃𝗲-𝗵𝘂𝗻𝗱𝗿𝗲𝗱 𝘁𝗶𝗺𝗲𝘀! 🤯
Fast Refresh Fixed in Nativewind 4.2.6#
A fast refresh issue affecting React Native 0.83+ and Expo SDK 55 and 56 has been fixed — newly added classes now reflect in real time while the app is running.
Update with npm i nativewind@latest.
Nativewind 4.2.6 is now available ✨ This version fixes fast refresh on React Native 0.83+ and Expo SDK 55 and 56. Adding a new class while the app is running updates in real-time again. No full restart needed. npm i nativewind@latest Thanks for your help @jackmekiss!
RNRepo Cuts Photobucket’s Android Build Time by 30%#
Software Mansion reported that Photobucket reduced its Android build time by 30% after adopting RNRepo.
Photobucket (@photobucket) saw a 30% reduction in Android build times after adopting RNRepo⏱️
React Native macOS App Opens Files 2× Faster Than Rust-Based Zed#
A diff tool built with React Native macOS was shown to render and syntax-highlight a folder’s git diff in 200ms. Separately, a React Native macOS code editor was reported to open, parse, and syntax-highlight files twice as fast as the Rust-based Zed editor.
Seriously though, React Native apps can be faster than native apps 🔥. I'm making a React Native macOS diffing app that git diffs a folder, and renders and syntax highlights it, in 200ms. And look at that scrolling perf 😍 "React Native is slow" is wrong.
React Native apps can be faster than native 🔥. I'm working on a React Native macOS code editor that opens, parses, and syntax highlights twice as fast as Zed, which is built in Rust. "React Native is slow" is wrong.
Claude Code Marketplace Plugin Added to serve-sim#
Install it with /plugin marketplace add evanbacon/serve-sim to get full-resolution device screenshots, file drag-and-drop, and path sharing via notification drag.
serve-sim now has a Claude Code marketplace plugin! /plugin marketplace add evanbacon/serve-sim Thanks @cypher_poet for the contribution twitter.com/Baconbrix/status/2…
New in serve-sim ⬦ Full resolution device screenshots ⬦ Drag and drop files to add to device (incl. apps) ⬦ Drag notifications to share paths with agents
One More Thing#
Saw jmeistrich’s post about a React Native app outperforming a pure-native implementation — honestly, that one caught me off guard! Sure, it depends on the case, but the old “React Native is just slow” line might not really hold up anymore.