T.J. Żelawski Profile
T.J. Żelawski

@_tjzel

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Tomasz Żelawski, React Native Open Source Developer @swmansion I do Worklets and Reanimated 🌈 He/Him

Kraków, Poland
Joined March 2023
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@satya164
Satyajit Sahoo
5 days
Just published a library to convert between Animated and Reanimated values. If you use a component that accepts/returns animated/reanimated values, but you use reanimated/animated values, you can now convert the value to the appropriate format. https://t.co/IJRQ6SAP5A
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@kacperkapusciak
Kacper Kapuściak
6 days
just applied as a speaker to @RNLConf! hope to 𝘴𝘩𝘢𝘬𝘦 up React Native devs so that we don't lose 𝘵𝘰𝘶𝘤𝘩 with reality 😉
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@thejsnation
JSNation | The key JS conference
14 days
.@iwoplaza invites you 🔥to his talk: "TypeScript on the GPU – Bridging the Gap Between Realms." Can’t wait to see you at JSNation US, Nov. 17 & 20!
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@_tjzel
T.J. Żelawski
15 days
Mom is going to be proud 😍
@reactuniverse_
React Universe Conf | Sept 2-4, 2025
15 days
🔹Meet the Speakers🔹 Single-threaded JS? Not anymore. @_tjzel (@swmansion) will show how react-native-worklets pushes concurrency in React Native and what happens when you take JS to its multithreading limits. Don’t miss this one 🎟️ https://t.co/45QjgvbuIY
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@_tjzel
T.J. Żelawski
17 days
I'm excited to announce I will be speaker at React Universe, just next week! 🥳 It's high time we talk Worklets on a big stage.
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@kacperkapusciak
Kacper Kapuściak
2 months
Join me for the Reanimated 4 live coding session here on X and @swmansion YT channel 🎥 We'll be learning the latest and greatest CSS Animations & Transitions 🐎 See you tomorrow at 5:00 PM CEST!
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@_tjzel
T.J. Żelawski
2 months
Come and see how the boys cook me 🍳
@swmansion
Software Mansion
2 months
We're joining @lukasz_app's live stream today to talk about Reanimated 4! 🐎 Come and grill @_tjzel about the future of RN animations today at 5 PM CEST: https://t.co/LH6OVQvDJT
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@_tjzel
T.J. Żelawski
2 months
The underlying algorithm got an upgrade as well. It only took me a week of fiddling with the equation to figure out how to reduce the amount of necessary numeric calculations 🥳
@kacperkapusciak
Kacper Kapuściak
2 months
One of the most noticeable changes in React Native Reanimated 4 is the change of the default withSpring configuration to a more snappy one👇 We strongly believe that this is a change for the better!
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@_tjzel
T.J. Żelawski
2 months
It's our biggest one yet 😈
@swmansion
Software Mansion
2 months
React Native Reanimated 4 is now stable and ready for production 🐎 Featuring CSS Animations & Transitions, multithreading with React Native Worklets and more.
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@_tjzel
T.J. Żelawski
2 months
Turns out fetch in worklets wasn't really that hard 😅 Also please ignore my 1K+ problems. Big thanks to @tomekzaw for letting me scrape his website from the UI thread 😈
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@swmansion
Software Mansion
2 months
Radon IDE 1.9 is here! 🧪 🌎 Radon Connect: Debug physical devices and external simulators 🏎️ Quickly switch between different project configurations 🎥 Emulate camera output on Android
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@_tjzel
T.J. Żelawski
2 months
If you want to test it in your app, keep in mind that Reanimated 3 doesn't work with standalone `react-native-worklets`. However, a nightly version of Reanimated 4 works just fine.
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@_tjzel
T.J. Żelawski
2 months
Libraries that fetch data will also have a hard time - `fetch` is not yet available on Worklet Runtimes. We aim to add it soon™. For now, libraries that focus on the UI are the best bet to use with Bundle Mode - like `react-native-wgpu` or `react-native-live-markdown`.
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@_tjzel
T.J. Żelawski
2 months
While the feature allows you to use virtually any library, there are some constraints. For example, some side-effects are problematic. A library that would directly import React Native can't be used on a Worklet Runtime. Don't worry, you will get a friendly error in that case.
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@_tjzel
T.J. Żelawski
2 months
Ultimately this will be a plug-and-play solution, without cumbersome configurations. However, it's not that simple. Bundle Mode needs APIs that aren't yet available in React Native. Please give a thumbs up on my PR so we can ship it to React Native faster https://t.co/qqgQWxjGxD
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github.com
Summary: With the development of react-native-worklets library I want to align it more with the tools inside React Native ecosystem and reduce the amount of hacks needed to provide multithreading J...
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@_tjzel
T.J. Żelawski
2 months
To run it, you need to install `react-native-worklets@bundle-mode-preview` and apply some patches to React Native, which expose additional APIs. The patches are non-invasive and won't change your app's behavior outside of worklets. More in the docs https://t.co/bOKENk2vrh
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docs.swmansion.com
Bundle Mode is a feature that gives worklets access to your whole JavaScript bundle - meaning that any code that's present in the bundle can be executed in any worklet and on any runtime. This means...
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@_tjzel
T.J. Żelawski
2 months
Every package you import in your application will be available to use in worklets. We call this feature "Bundle Mode". This is so because worklets and your app now share the very same JavaScript bundle.
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@_tjzel
T.J. Żelawski
2 months
We did it! You can finally use third-party libraries in worklets - with `react-native-worklets`. Jump in the thread to learn more 👇
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