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React Native Performance: JavaScript Thread ๐Ÿง  vs UI Thread ๐ŸŽจ Explained

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Premiered Oct 1, 2025
5:01

React Native apps run on multiple threads, but the two most important are the JavaScript thread and the UI (main) thread. In this video, weโ€™ll break down how they work, what causes them to slow down, and how to optimize your appโ€™s performance. ๐Ÿš€ ๐Ÿ”‘ What Youโ€™ll Learn ๐Ÿง  JavaScript thread responsibilities (state, logic, events, navigation) ๐ŸŽจ UI thread responsibilities (rendering, gestures, animations) ๐Ÿšจ Common performance blockers for both threads ๐Ÿ” How to detect issues with Flipper, Xcode, and Android Studio โšก Optimization strategies for JS and UI threads ๐Ÿš€ How the new architecture (Fabric & TurboModules) improves performance ๐Ÿงช Real-world code examples of bad vs good practices Perfect for React Native developers who want to avoid app freezes, improve FPS, and deliver smooth animations. โฑ Chapters 0:00 โ€“ Intro 0:40 โ€“ What are Threads in React Native 2:00 โ€“ JavaScript Thread Responsibilities 3:30 โ€“ Common JS Thread Blockers 5:10 โ€“ UI Thread Responsibilities 6:30 โ€“ Common UI Thread Blockers 8:00 โ€“ The Bridge & Bottlenecks 9:20 โ€“ Detecting Performance Issues 11:10 โ€“ Optimizing the JavaScript Thread 13:20 โ€“ Optimizing the UI Thread 15:00 โ€“ New Architecture (Fabric & TurboModules) 16:20 โ€“ Real-World Example (Bad vs Good) 17:40 โ€“ Summary & Final Tips ๐Ÿ“š Resources & Links ๐Ÿ“Œ React Native Playlist โ†’ https://youtube.com/playlist?list=PLEnLIMmMxb5oA7rEnHtQ6lS-v-NQ4lJjK ๐Ÿ“Œ GitHub Repo (Source Code + Notes) โ†’ https://github.com/coding4dev ๐Ÿ“Œ Coding 4 Dev Website โ†’ https://coding4dev.boadtechnologies.com ๐Ÿ”— Follow Coding4Dev on Social Media: Instagram โ†’ https://instagram.com/coding_4_dev X (Twitter) โ†’ https://x.com/Coding4Devs GitHub โ†’ https://github.com/coding4dev LinkedIn โ†’ https://linkedin.com/company/coding-4-devs ๐Ÿท SEO Tags react native performance, react native js thread vs ui thread, react native optimization, react native performance bottlenecks, react native ui freezes, react native fps, react native new architecture, fabric turbomodules react native, coding4dev react native ๐Ÿ”ฅ Hashtags #ReactNative #Performance #JavaScriptThread #UIThread #MobileDev #Coding4Dev #SmoothApps

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React Native Performance: JavaScript Thread ๐Ÿง  vs UI Thread ๐ŸŽจ Explained | NatokHD