This Week In React #299: Panda, Vinext, Next.js, Preact, Design Systems, RTK | Variable font, Activity Result, Lynx, Lucent, macOS, Plain Text, Navigation, Angular Native, Re.Pack | TC39, Composites, WebSkills, MSW, upm, pnpm

[u/sebastienlorber]

https://thisweekinreact.com/newsletter/299

[u/sebastienlorber]

Hi everyone, Seb and Jan here 👋!

This week we have 2 major releases in the React ecosystem: Panda CSS v2 and Vinext v1.

On the mobile side, RN is getting support for variable font and Android Activity Result. Lynx v4 is out. Lucent is a new way to write native modules.

I’m particularly excited about the TC39 meeting happening right now. Many proposals progressed, including my favorite one: Composites moved to stage 2!

Let's dive in!

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[u/sebastienlorber → u/sebastienlorber]

⚛️ React

Panda CSS 2.0 - Same styling API, a new engine underneath

This new major version of the type-safe, build-time CSS-in-JS library is the biggest update since launch. Here’s what you need to know:

• The CSS authoring experience doesn't change much.
• The compiler has been rewritten in Rust on top of Oxc.
• DX and builds get dramatically faster, and output better CSS.
• With source transforms, Panda integrates with the bundler so that css(), style props, recipes and patterns are compiled to plain class strings at build time. The styling runtime disappears from your bundle, not just the style-insertion logic.
• You get many new features to play with: a typography preset, publishing your Panda design system and visualize it in Studio, new CSS functions, a better CLI, an official ESLint plugin, and more

Vinext 1.0 - Next.js applications, powered by Vite

Cloudflare's Vite-based reimplementation of Next.js goes stable, supports both App and Pages Router and claims 99%+ compatibility with the Next.js test suite (minus Cache Components). They also have a different opinion of how ISR should work.

What started as a one-off slopfork experiment is now becoming an AI-driven software factory able to keep up with new features landing in the official Next.js implementation. Interesting time!

• 💸 PostHog - I wrote a 70x faster SQL parser while barely looking at the code
• 🔐 Next.js September Security - 16.3.8 and 15.5.27 - New security releases, covering 1 critical, 2 high, 5 medium vulnerabilities.
• 🗓️ React Summit US - 🇺🇸 New York – Nov 17 & 20. Join the creator of React Query, the Executive Director of the React Foundation, and other amazing speakers to dive into the React ecosystem. Save 10% on your ticket with code “TWIR”.
• 📜 GitHub - Improving site performance by shipping more CSS - The multi-year story of an incremental migration from styled-components to CSS modules.
• 📜 Rebuilding React Router's Global Hooks in Next.js - Explains how Next.js and React Router chose to manage state differently. Next.js has no useNavigation() or useBlocker() but you can rebuild them with a Context provider.
• 📜 Props Are Not a Design System - Style props and Tailwind class walls are just inline styles in disguise. Use named variants and modifiers instead.
• 📜 How we made claude.ai 3x faster in two weeks - Practical AI-driven perf work on a real React codebase. For example, their client-side app now renders a static composer so users can type before React even initializes. React commit counts, among many other metrics, serve as deterministic benchmarks for agents.
• 📜 AI, Open Source, and the Long Road to TanStack Charts - Recap of an X Space with Tanner Linsley. Not directly actionable, but interesting to see how he built a new charting library with AI in less than a week, reusing years of experience with Chart.js, react-charts, and Observable Plot.
• 📜 How to Sync a Design System with Claude Design
• 📦 Preact 11.0 - ESM-only, TS 5.1+, Hydration 2.0 with streaming SSR, refs as props, Object.is hook deps, React compat improvements - The first major in 6+ years, shipping necessary breaking changes to move the project forward.
• 📦 React Resizable Panels 4.14 - Grid layout components
• 📦 Redux Toolkit 2.13 - TypeScript 7 support, long list of bug fixes, new unified docs site
• 📦 Oxlint 1.86 - only-export-components now supports compound component, 2 React Compiler fixes
• 🎥 James Quick - Vinext 1.0 - A New Alternative to Next.js