React Native’s New Architecture positions it as a worthy competitor to Flutter

[gandharva]

As a developer who has always been passionate about creating fluid, high-performance mobile apps, React Native’s frequent FPS drops and frequent jankiness left me frustrated. With its asynchronous bridge and challenges in rendering at a consistent 60 FPS, React Native often fell short of native app performance. But now, React Native 0.76 has introduced a New Architecture that promises to tackle these long-standing issues. Let’s dive into what’s changed and why I’m excited about this update.

What’s New in React Native’s Architecture?

The React Native team has taken a transformative approach, rebuilding the core structure to enhance performance, responsiveness, and compatibility with modern React features. Here’s a breakdown of the most impactful changes:

1. Native Module System Reimagined

• Synchronous Access: The New Native Module System eliminates the need for an asynchronous bridge. React Native apps can now call native modules synchronously, significantly speeding up interactions and reducing lag. This allows JavaScript and native code to communicate directly through a JavaScript Interface (JSI), minimizing serialization bottlenecks.
• Type-Safe Integration: With Codegen support, modules are now type-safe, reducing crashes due to type mismatches and improving cross-platform stability. This also streamlines development as native modules are now lazily loaded, reducing app startup time and memory usage.

2. New Renderer Written in C++

• Concurrent Rendering: The New Renderer can handle multiple tasks across multiple threads. For example, urgent tasks (like user inputs) can be prioritized over background tasks, which enhances responsiveness and reduces instances of janky transitions.
• Thread-Safe Layout Reads: The new renderer allows layout to be read synchronously across threads, which is particularly useful for positioning elements accurately in real-time, like tooltips or dynamic UIs. This was previously impossible in the older architecture and caused frustrating delays and frame drops.

3. Event Loop Overhaul

• Closer to Web Standards: The New Architecture’s Event Loop now aligns with web specifications, allowing for features like microtasks, MutationObserver, and IntersectionObserver. This creates a consistent behavior between React Native and React DOM, making it easier for developers to maintain cross-platform apps.
• Task Prioritization: With an improved event loop, React Native can now interrupt low-priority tasks to handle urgent events, such as user interactions, giving a more seamless and responsive feel to apps.

4. Goodbye to the Asynchronous Bridge

• Direct Native Access: By removing the asynchronous bridge, the New Architecture eliminates delays in communication between JavaScript and native code. This also reduces startup time and minimizes the need for workarounds, which previously impacted app performance.

What This Means for Performance and Developer Experience

This New Architecture brings React Native closer to native performance. By allowing synchronous native module access and adopting Concurrent React features (like Suspense and automatic batching), the New Architecture provides a smoother, jank-free experience even in complex UIs.

For developers, these changes mean more control, stability, and compatibility with modern React practices. This re-architecture also makes React Native much easier to scale, as it’s less dependent on hacky fixes and provides a direct path to building truly responsive, high-performance apps.

Why I’m Hopeful
With the New Architecture, React Native now has the technical foundation to support high FPS and smoother animations while retaining its flexibility and cross-platform advantages. It addresses core performance challenges like FPS drops and improves interaction responsiveness— it's been a long wait.

This overhaul means that developers can now build more ambitious apps, knowing the infrastructure can handle sophisticated UI requirements without compromising on user experience. What would be your reason to pick Flutter over React Native?

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[gandharva]

Release announcement- https://reactnative.dev/blog/2024/10/23/the-new-architecture-is-here