📨 #304: Next.js, Compiler, Redux Toolkit, Suspense, Resizable Panels, Preact, Redact | RN 0.89 RC, Vega OS, Screens, Hermes, WebView, Unistyles, tgfx, Pager View | Node.js, Parcel, Rspack, Actions, Vitest, jsdom, HTML-in-Canvas

Hi everyone, Seb and Jan here 👋!

Calm week on the React side, but we found a few interesting Next.js PRs to look at and a few Async React blog posts.

On mobile, the first React Native 0.89 RC is here, with lots of performance work. Amazon Vega OS 2.0 brings RN 0.83 to every Vega-powered Fire TV. Hermes gets a full Intl implementation, still in preview. Screens v5 is coming.

Elsewhere, GitHub Actions will block pull_request_target by default. Node.js 27 is the first alpha of the new release model. Parcel 3 is a much faster Rust rewrite.

Let's dive in!

As always, thanks for supporting us on your favorite platform:

• 🦋 Bluesky
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• 👔 LinkedIn
• 👽 Reddit

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My favorite resource for keeping up with the React community!

Evan BaconEngineering Manager - Expo

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⚛️ React

• 💸 Testing Frontend - Lessons from over a million lines of TypeScript at Palantir - Skip component tests and let Meticulous do the rest
• 🔐 Next.js November security releases 16.4.5 & 15.5.29 - Fixing 7 medium vulnerabilities
• 🐦 Remotion - New Studio editing experience - A better, more interactive timeline that’s still code-based but now matches the UX of video editing tools better.
• 👀 React Compiler PR - Preserve source locations for accurate source maps - This should help fix source map issues when using the React Compiler, bug reports in various downstream projects.
• 👀 React Concurrent Store PR - Ricky Hanlon runs React's own state tests against the unofficial ponyfill
• 👀 Next.js PR - router.experimental_prepare() to start a navigation on pointerdown and commit it on click - This is quite an exciting feature I’ve been wanting for years. There’s a delay between pointerdown and click events. Now you can “prepare” a navigation ahead of time, even if the user hasn’t really clicked your link yet. Once the click is confirmed, you commit the pre-warmed navigation that should feel faster. This may be integrated into the <Link> component eventually.
• 👀 Next.js PR - create-next-app always uses the App Router, no router choice prompt
• 👀 Next.js PR - Experimental Go Route Handlers with route.go files - The Next.js team is prototyping native language support for CPU-intensive server work next to your React app, starting with Route Handlers and Proxy in Go.
• 📜 React.lazy, Suspense and the Hidden 300 ms Delay - A React.lazy component always suspends on its first render, and React throttles Suspense reveals to 300ms to avoid flicker, which can be a problem in some cases.
• 📜 Async React & Progressive Server Actions - When using Server Actions with client-side optimistic UI, it’s easy to break your form progressive enhancement behavior. Thankfully, you can restore it with a simple trick: only wire the optimistic action after hydration.
• 📜 Understanding React internals - A 6-chapter tour, from Fizz and Flight on the server to hydration, lanes and the commit phase, with code taken from React's source.
• 📜 Writable Derived State: Stop Synchronizing State - Instead of syncing server data into local client data with useEffect, you could simply use clientData ?? serverData. The client data can be null after a server refresh.
• 💸 PropelAuth - How to Build a Good Consent Screen for OAuth And MCP
• 📦 Redux Toolkit 2.14 - Faster dispatch, RTK Query cache entry selectors, DevTools action sanitizer, many RTK Query fixes - There’s also a new 2.x and 3.0 roadmap that announces what’s coming next.
• 📦 React Resizable Panels 4.16 → 4.18 - New <Workspace> component for IDE-like layouts, draggable and collapsible tabsets
• 📦 Preact 11.1 - preact/compat/compiler-runtime for React Compiler apps
• 📦 TanStack Redact 0.3 - Webpack and Rspack plugins for browser SPAs, Rsbuild setup guide
• 📦 Inertia 3.10 → 3.11 - Live props refreshed by broadcast events (Laravel Echo), QUERY HTTP method, stale navigation fixes
• 📦 Skullet - Skeleton loading states measured from your real components
• 📦 ESLint Plugin React “You Might Not Need An Effect” 1.1 - Support renamed React hook imports
• 📦 safe-mdx 2.0 → 2.1 - Render MDX in React without eval, streaming parser for LLM output

Don't miss the next email!

If every newsletter was as informative, the world would be a better place!

Mike GrabowskiCTO and founder - Callstack

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📱 React-Native

Vega OS 2.0

Vega OS 2.0 is out now on every Vega-powered Fire TV, bringing RN 0.83: React 19, the compiler, Hermes v1, and real DevTools.

It also brings native APIs, agent-assisted migrations, and stable minors with one major a year.

• TV focus states - new boxShadow and outline props, plus compat updates for Navigation, Reanimated, and Lottie.
• Beyond RN - native APIs for task scheduling and custom UI, with hybrid-UI and periodic-task sample apps.
• DevAssistant - docs AI with a Vega domain selector and page-level context, so less doc-hunting.

• 💸 build mode - What happens to engineers when AI writes all the code?
• 👀 React Native 0.89 RC - Faster text layout and native module calls, legacy bridge APIs removed, useAppState() hook, experimental_onSafeAreaInsetsChange, global structuredClone - A sneak peek of the upcoming version, due Dec 7, with lots of performance work and legacy architecture cleanup.
• 👀 React Native PR - Public visual regression testing for RNTester in CI - Rendering regressions now surface on public PRs. Unlocks porting the rest of the internal jest-e2e rendering tests.
• 🔐 Better Auth security release - Including a critical fix in the Expo integration
• 🐦 Full Intl implementation for Hermes, based on ICU4X - ~19MB per platform for complete Intl. RN podspec needs to be updated, so this is only a preview.
• 📜 Apple Developer Program explained: free vs paid - Breakdown of tiers and how Expo keeps costs at $0 until you're ready to publish.
• 📜 A WebGPU cat puzzle game shipped in three days on Expo, with an AI agent as the QA team - Case study of a solo dev shipping a GPU game to the App Store and web in 3 days with one TypeScript engine, TypeGPU shaders, and agent testing.
• 💸 Maestro MCP - How to get your coding agent to verify UI changes on iOS and Android
• 📦 Screens 5.0 beta - RN 0.88, iOS contained modals, Android Stack v5 animation presets, iOS 27 header minimization controls, Liquid Glass opt-out for form sheets
• 📦 WebView 17.0 → 17.1 - Public RN codegen APIs, RN 0.80+ required, Android profile prop for isolated cookie jars
• 📦 Nitro Fetch 1.10 - XMLHttpRequest bridge, non-persisted native prefetch(), pre-warmed Cronet engine with configurable cache
• 📦 Pager View 10.0 - Rewritten as a Function component, native view ref, keyboard and nested ScrollView fixes
• 📦 Maestro 2.12 - Queue priority for Cloud uploads, Xcode 27 simulators, faster Android typing
• 📦 Unistyles 3.7 → 3.8 - Zero Babel transforms with the Metro integration, 2–8x faster web style updates, DevTools performance track, RN 0.85+ required
• 📦 Safe Area Context 5.11 - Corner-adapted insets, Android subtree insets, web scroll fix
• 📦 RN TGFX - Declarative GPU 2D canvas powered by Tencent's tgfx and Nitro
• 📦 Skia 3.9 - colorSpace prop, async readbacks, background GPU + Imagination fixes
• 📦 NativeKeel - Library scanner that checks dependencies for breakage
• 🤖 Simlock - Turn Mac into a simulator cloud that manages itself
• 🤖 Agent-Desktop - Computer use CLI for AI agents on macOS, Windows and Linux, through the accessibility tree
• 🤖 Argent 0.31 - HarmonyOS support, faster MCP captures
• 🤖 RAG 0.11 - async LLM runner, context-length fitting, worklets 0.13 support
• 🤖 How to make your CI 10x faster with e2e? - Run only tests that matter. Use a decision-based model to filter by what the change touches instead of the whole suite on every push.
• 🤖 Argent e2e Tutorial: Record a Mobile Test and Run It in CI - The agent records the test once in YAML, then CI replays without any model.
• 🎙️ Software Mansion podcast - "Maybe React Native Is Impossible" with Chas Jhin from Discord

🔀 Other

• 🔐 GitHub Actions - pull_request_target blocked by default in public repositories from December 2 - Good news for supply chain security. This “feature” led to compromises like TanStack, PostHog, Nx, and more.
• 📦 Chrome 157 - HTML-in-Canvas stable: Interactive DOM inside 2D, WebGL, and WebGPU - Chrome 157 is now out, including this exciting feature (unflagged) that unlocks many creative use cases.
• 📦 Node.js 27.0 alpha - V8 15.6, npm 12.1, default heap size changes, --allow-env permission, native fs.glob, net/promises API - The first Alpha of the new release model, not based on even/odd numbers anymore. It becomes Current in April 2027 and LTS in October 2027.
• 📦 jsdom 31.0 - New CSS engine - Faster selector queries and repeated style reads. Now supports many new CSS features such as cascade layers, nesting, scoping, and more.
• 📦 Parcel 3.0 alpha - Rust rewrite, up to 100x faster, standalone binary, native plugins, smarter code splitting
• 📦 Rspack 2.3 - SWC Next parser, 5–20% faster builds, up to 27% lower memory, less duplicate code across chunks, CSS improvements, new cache (experimental)
• 📦 Vitest 5.1 - --since-last-run, interactive snapshot review, Trace View on failure by default, faster Browser Mode mocking, 5–10x faster Istanbul instrumentation
• 📦 Babel 8.1 - Import Bytes/Text, filtered namespaces, source map range mappings (experimental), @babel/eslint-plugin configs
• 📦 tRPC 11.20 → 11.24 - Per-procedure error formatters with .errors(), stable localLink, TanStack Query handles (unstable), Next.js App Router cache tags
• 📦 x18n - Lint, view and manage i18n files for any framework

🤭 Fun

See ya! 👋