In this webinar recording, Callstack Software Engineer Szymon Chmal dives into Part 2 of the 2025 Ultimate Guide to React Native Optimization, continuing the deep dive into JavaScript performance issues, and how to solve them.

From misused debounce functions and costly Redux selectors to over-rendering component trees and misconfigured state logic, this session shows what actually slows down your React Native app, and how to fix it. Expect practical takeaways, real examples from performance audits, and a hands-on demo app to guide you through each topic.

If you’ve ever felt like your app is doing too much rendering, lagging under simple input, or just not feeling “native enough,” this webinar is for you.

What you’ll learn about JavaScript performance optimization

• How to fix broken debounce patterns that silently kill your app’s responsiveness.
• How to isolate state updates using the Context API to avoid re-rendering your entire screen.
• What Redux selector misuse looks like (and how to fix it with createSelector and stable outputs).
• How to get real gains with Concurrent React APIs like ^{useDeferredValue}, and what they won’t solve.
• How to offload heavy synchronous logic using Worklets and keep your main thread unblocked.

Why you should give this webinar a shot

This is more than theory, it’s code-level insight from real audits, covering mistakes seen in production apps. Szymon shares practical strategies, explains performance trade-offs, and shows you exactly how to apply them in your own projects.

By the end of this session recording, you’ll have:

• A stronger grasp of how to debug and resolve common JS performance issues in React Native.
• Examples of context management, list rendering, and Redux setup that don’t scale, and how to replace them.
• New ways to use React Native’s evolving architecture and tooling to your advantage.

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