I gave a talk today at @nordicjs.com about shipping Node.js packages in 2025...or how to transition from shipping dual/faux-ESM/CommonJS to shipping ESM directly! Slides at github.com/joyeecheung/...

Best conference ever kicking off LFG 🇪🇸 @reactalicante.es

we now have some new @e18e.dev docs on best practice of publishing npm packages this documents the recommended basics for a secure publish workflow and gives some pointers for further security/tools/etc this is a _very_ opinionated subject, so do ping me if you have feedback!

<Activity> - The most exciting React feature just came out! Hide a React subtree and unmount its Effects while preserving its state, and keep rendering it with lower priority. Unlocks very exciting pre-rendering patterns along the way! More Activity modes are coming

React 19.2 is now available! This release includes Activity, useEffectEvent, React Performance Tracks, partial pre-rendering, and more: react.dev/blog/2025/10...

one of my *BIG* pieces dropped yesterday so reprising for the UK shift and the US morning folks: why did it take so long for the web to get a real test suite and why do we need it so much?

This month, @vcarl.com , @mojavad.bsky.social and I go over upcoming React features, debate React's innovation, look at some RSC updates, recap the NPM hacks, and highlight a boatload of useful links!

Any react-window users interested in trying out the pre-release with support for dynamic content? Docs can be found at: react-window-git-dynamic-row-heights-alt-brian-vaughns-projects.vercel.app/list/dynamic...

🔥 New blog post! Covering, among other things: - Why making simple things easy and complex things possible is not enough - How to maximize your UI’s signal-to-noise ratio - Why you can’t uncover friction through user feedback - How to prioritize user needs lea.verou.me/blog/2025/us...

oh i guess useEffectEvent is progressing to Canary! clunky name but i’m happy the docs i wrote for it a few years ago ended up needing essentially no changes

was a great @e18e.dev community call with @acemarke.dev! a lot of interesting stuff around making immer faster - CPU profiling, etc might have to make these guest community calls a regular thing :D

we now have an @e18e.dev github action which can diff your dependencies in PRs things like: - change in trust level (loss of trusted publisher) - adding >threshold dependencies - adding >threshold install size - bundle size difference (vs main) - duplicate deps early days so please give feedback!

Come hang out! 🙌

Write good commit messages. Yes, even when you’re working on a solo project or one where you work with just one or two other people. Your memory isn’t as good as you think it is (almost no one’s is!) and you’ll be glad you wrote it down. Tonight’s example for me was this: github.com/true-myth/tr...

If anyone's interested, @43081j.com and I are planning to stream looking at my WIP Immer perf rewrite and discussing perf profiling techniques tomorrow, 1 PM ET in the E18E Discord: e18e.dev/learn/ No idea how this'll work out, but hopefully it'll be informative and maybe we'll fix more perf :)

10/10 Summary: AI agents are very useful. But creation itself is irreplaceable. If you always delegate creation, you lose mechanical sympathy, and eventually effectiveness. Question: how to preserve that effectiveness while still getting the most from agents.

9/10 The longer-term risk is erosion of expertise. If engs mostly review and rarely create, they become managers. And managers, no matter how capable, eventually lose the ability to intuitively understand the system. They lose mechanical sympathy.

I've made significant further progress on my Immer perf rewrite, and I now feel fairly confident in saying it's ~50% faster than Immer 10 current! (varies 20-90% per benchmark) Still need to reimplement patches and do cleanup, but looking good! Further details here: github.com/immerjs/imme...

Someone asked on Reddit today how they could use react-window to render a list of images of varying, unknown sizes, so I posted an demo with some example code showing how I would approach it. react-window.vercel.app/list/images

New post on big general type-checker improvements. How `specification.md` can be used to test both features and performance. And perhaps what is up for version 0.1.0...

ECMAScript excitement 😉 This week TC39 advanced these proposals 🎉 3️⃣ Non-extensible applies to Private 2️⃣.7️⃣ Import Bytes 2️⃣.7️⃣ Iterator Chunking 2️⃣ Native Promise Predicate 1️⃣ Array.prototype.pushAll 1️⃣ Native Promise Adoption

This is a collection of @rspack.dev and RSBuild plugins rolled up into a single rsbuild plugin to enable running of @reactrouter.com's RSC mode in RSBuild. It supports - `import with { env: "react-server" }` - `use client` - `use server` It needs - code splitting - action encryption - css handling

For the first time in the 4 years I've been doing Friday streams, I will be having a @react.dev Core Team member as a guest. I'm excited to welcome @ricky.fm on to talk all things React. Past, present, future. www.youtube.com/live/3vw6EAm...

I do love a good "I have put insane amounts of effort into an obscure technical challenge" blog post, and this one qualifies :) This is an impressive post detailing how the author ported their TS-based programming puzzle game to work under.... _MS-DOS_?!?!?!_: jimb.ly/2025/09/23/q...

React Router Framework Mode now has preview support for React Server Components Just swap your vite plugin and you can: - Return Server Components from loaders/actions - Opt routes into Server Components - Leverage Server Functions

We’re live!! My brand-new course, “Whimsical Animations”, is now available. 🥳🎉 whimsy.joshwcomeau.com I’m so excited to share all of my animation tools and techniques with y’all. 😄

Rari is early and experimental. We're exploring React Server Components with custom RSC streaming, client component registry, Rust runtime, and HMR for server components. We've pushed one boundary that breaks React's RSC rules—should we keep innovating or align with standards?

I added parallel and recursive route rendering to Twofold, which kind of blew my mind. It's the first time I've used a React pattern that specifically takes advantage of the two phase server/client render. Wrote about it here: twofoldframework.com/blog/paralle...

🚀 Announcing TanStack.com Start v1 Release Candidate! Upgrades ↓ ✨ Unified Route Tree: no more server-specific files 🔐 Type-safe middleware & server context upgrades 🛡 CSP/nonce support ⚡ Now works with any native Vite Env plugin 🌀 Zero-JS: any server handler can render!

i am live for the first time in like a year get in here and watch me fail to rewrite redux docs: twitch.tv/crutchcorn

No additional code / flamecharts / benchmarks for this _yet_... but I'm hacking on the WIP Immer perf rewrite branch again tonight. I _think_ I might have finally pulled almost all the pieces together... and rerunning the full benchmarks I'm seeing anywhere from 30-60% faster than v10? :)🤞🤞🤞

Redux is fantastic and just gotten better and simpler. It’s made debugging production issues so much easier. No more trying to repro, we have periodic snapshots of state and just play msgs back. Sometimes we even reuse those snapshots for tests so we never see those production issues again. Easy…

It's funny how most online criticism of Redux hasn't changed since 2017. Comparisons today are vs Zustand, Jotai and React Query, not Mobx, but much of The Discourse is the same. I even answered many of those questions in my 2017 "Tao of Redux" posts: blog.isquaredsoftware.com/2017/05/idio...

SquiggleConf 2025 was an absolute, incredible blast. We had a wonderful time learning with you all. A HUGE "thank you!" to all our attendees, speakers, sponsors, and volunteers for making this a wonderful experience. We can't wait to see you in Spring 2027. 💙

I got into tech because it’s fun to take things apart, see how they work, and put them back together — or rearrange the parts into something brand new. it definitely feels like the new ethos is “bro why bother to learn? caring about that stuff is cringe, just go FAST bro” and that bums me out

more than once!!

Rumor has it that they even have dinner together 🤔

@squiggleconf.com was amazing! I met so many incredible people, heard captivating talks that got into the gritty details, and I had wonderful conversations about complex and fascinating topics.

Everyone go to SquiggleConf Spring 2027

Absolutely this! The next @squiggleconf.com is being planned for Spring 2027. YOU SHOULD BE THERE! IT WILL BE WONDERFUL! It's a fantastic conf put on by amazing people who care deeply about giving devs a place to come together. JOIN US NEXT TIME!

It's the total opposite. Other OSS library maintainers know your struggle. They can relate. They have similar problems and success stories. They are like-minded. I've had the best discussions with @acemarke.dev and @phry.dev at various conferences. It's what keeps me going there 🙌

Some people are just here for the "drama" I guess so they really want there to be a feud and cannot comprehend that this is not how OSS works. People who do things for free and for fun usually don't fight with others who do the same. Why would we?

“Internal tooling is what keeps the boring parts boring.” - love this quote from @codebyte.re at @squiggleconf.com this morning!

TIL: the "sync" in @react.dev's useSyncExternalStore isn't for "synchronise", it's for "synchronous". As: it's not for synchronising against an external store, It's for synchronously (ie: disabling concurrent features) updating against a store's changes. h/t @tkdodo.eu 🤯

We are having such a lovely time hosting everybody at the aquarium today. Thank you to our wonderful attendees, speakers, and sponsors: you are what makes this conference wonderful! 💙

It's all about that mutual uplift that I think is unfamiliar to many outside of the OSS world. So many amazing convos with mutuals in the same/similar spaces as ourselves. Especially when someone gets it in their mind of "new" vs "old" it's hard to divorce one's tools from one's identity I think.

Outing myself here: It's so surprising how many "us vs them" arguments are made IRL when talking with those unfamiliar with how OSS broadly works. IE: I love my peers in the Form space. I am so excited to see @joshuakgoldberg.com's upcoming CLI generator tool become v1. Jotai and Zustand rock.

A person I know and trust said he's talked to folks who think we Redux maintainers are somehow feuding with the TanStack maintainers or that we're enemies. Absolutely _not_ the case! @tkdodo.eu and @tannerlinsley.com are friends! They're awesome, and we routinely chat and share advice.