Is this the most exciting React Native feature yet? | Mind Spills by Admir Saheta

Is this the most exciting React Native feature yet?

Ah, React Native. Since its debut in 2015, when Facebook—now Meta, naturally—graciously bestowed it upon the world, it has undergone a transformation nothing short of riveting. What began as an experimental dalliance with React’s declarative UI philosophy in the realm of mobile apps has blossomed into a fully grown, dare I say, fabulous framework. It now underpins countless iOS and Android applications across the globe with the kind of elegance you’d expect from something born of Silicon Valley ambitions.

Companies like Microsoft, Shopify, and Coinbase have embraced React Native with aplomb, crafting apps that are not only technically robust but borderline transformative. These aren’t just apps; they’re ecosystems that redefine user interactions, delivering native-esque fluidity while stealthily elevating developer productivity to near-cosmic heights.

It’s the kind of technology evolution that doesn’t just change workflows—it reshapes the entire game. A true marvel, if you will.

As expected, React Native had its share of challenges, like performance bottlenecks, native module integration complexity, and the infamous ‘bridge’ architecture. All these problems necessitated a transition toward a new architecture. This, in turn, has generated the largest architectural overhaul in React Native’s history.

With the arrival of React Native 0.76, the framework became completely extraordinary, with a totally new architecture that redefines performance, scalability, and developer experience.

Terms and Concepts

Before we dive into the shiny new features, it’s essential to get familiar with a few engineering terms. Think of it as preparing the palate before the grand tasting. Understanding these concepts will make it so much easier for you fine folks to grasp the brilliance of the changes this release brings.

1. Metro Bundler

Ah, Metro. It’s the unsung hero of React Native. Imagine it as the impeccable concierge of your app’s JavaScript—guiding it through its transformation and ensuring it’s ready for the mobile world. Metro does a little bit of everything, including:

  • Transmuting modern JavaScript into something that runs smoothly across all devices.
  • Orchestrating dependencies and neatly packaging everything into a single bundle.
  • Ensuring that when you make changes, the app refreshes at lightning speed.
  • And yes, it even takes care of module resolution and asset management.

This release comes with optimizations that make Metro even faster and more efficient, resulting in quicker resolutions and shorter build times. Efficiency is key, wouldn’t you agree?

2. Native Modules

Ah, Native Modules—the elegant bridge between JavaScript and native code. With React Native, we need these modules to make the app speak the native language of each platform, whether it’s Java/Kotlin for Android or Objective-C/Swift for iOS. But now, with the New Architecture, we’ve got something a bit more refined—type-safe Native Modules. This means smoother interaction between JavaScript and native code, and the best part? The removal of that cumbersome bridge, leading to less overhead and vastly improved performance.

3. The Old vs. New Architecture

Let’s take a moment to reflect on the past. The old architecture, well, it relied on the “bridge” for communication between JavaScript and native code—a rather quaint, albeit limited, setup. This bridge had its fair share of issues:

  • Data had to be painstakingly serialized and deserialized.
  • Communication was strictly asynchronous—not exactly lightning fast.
  • And, oh, that bridge? It could become a performance bottleneck.

Now, enter the New Architecture—a true marvel of modern engineering. It’s built to overcome these very limitations, ushering in an era of fluidity and speed.

4. Understanding JSI and the New Bridge

Now we get to the heart of the New Architecture: JavaScript Interface (JSI). The JSI eliminates the old bridge entirely, allowing JavaScript and native code to communicate directly. Yes, directly. No more serialization. No more waiting. Here’s the magic:

  • Direct communication between JavaScript and native code.
  • Synchronous communication, for that snappy responsiveness.
  • Access to memory like never before—yes, between the JavaScript and native layers.
  • No need to bother with JSON serialization. It’s like cutting out the middleman.

5. How React Native Works

Now, when it comes to the inner workings of React Native, it’s all about reconciliation—where JavaScript updates the UI, translating those changes into native views via the bridge. However, with the New Architecture, the bridge is a thing of the past. Enter the Turbo Module system, which processes calls directly, leading to a seamless and incredibly swift experience.

6. Fabric: The New Rendering System

Fabric, darling, is the pièce de résistance in this grand architectural overhaul. It’s designed to elevate React Native to new heights by offering the following:

  • Direct manipulation of native views from JavaScript—think of it as wielding a finely crafted instrument.
  • Support for concurrent rendering, which improves performance and responsiveness.
  • Better integration with native UI components, making your app feel even more like a native experience.
  • Reduced memory footprint—lean and mean.

7. Codegen and Turbo Modules

Codegen is like the smart assistant that automatically generates native code for your modules and components, reducing errors and ensuring type safety. Turbo Modules, on the other hand, bring a new level of efficiency, enhancing modularity and making custom functionalities a breeze to integrate.

Example, if you will:

import type {TurboModule} from 'react-native/types';
import {TurboModuleRegistry} from 'react-native';
 
export interface Spec extends TurboModule {
  multiply(a: number, b: number): Promise<number>;
}
 
export default TurboModuleRegistry.get<Spec>('Calculator');

8. Async Rendering

One of the most exciting aspects of the new architecture is async rendering. By allowing React Native to process UI updates asynchronously, apps can be more responsive and handle complex updates in parallel without blocking the UI thread. This results in smoother animations, faster load times, and a more fluid user experience. It also opens the door for improvements in how we handle large-scale rendering tasks, such as lists with hundreds or thousands of items.

Async rendering optimizes performance by splitting updates into smaller, non-blocking chunks, allowing the UI to remain responsive even during heavy computation. This change is expected to significantly reduce frame drops, a common performance issue with mobile apps.

9. Hermes 2.0

And now, let’s talk about the cherry on top: Hermes 2.0. Hermes is Facebook’s open-source JavaScript engine tailored for mobile environments. In React Native’s new architecture, Hermes plays a critical role in enhancing the overall performance of JavaScript execution.

With the release of Hermes 2.0, you get:

  • Faster startup time—your apps load almost instantly.
  • Improved memory management—optimizing resources more efficiently.
  • Enhanced debugging and performance tools—making your dev experience smoother.
  • Compatibility with modern JavaScript features, which ensures your app remains future-proof.

The new version of Hermes is designed to take full advantage of the turbo modules and async rendering systems, allowing developers to squeeze every bit of performance out of their applications. This makes it a key component of the new React Native architecture.

10. The Future of React Native

So, what’s next for React Native? With this new architecture, the framework has reached a tipping point where performance, scalability, and flexibility are no longer a concern. React Native is now capable of handling complex, resource-intensive applications with ease, and this is just the beginning.

The community continues to push forward with exciting initiatives, including:

  • Improved tooling and diagnostics.
  • Enhanced native integration for both iOS and Android.
  • Even tighter collaboration with the broader JavaScript ecosystem.
  • New capabilities for augmented reality (AR) and virtual reality (VR) apps.

React Native is set to dominate the cross-platform mobile development space for years to come. The most recent updates show that the team is deeply committed to making it a better, faster, and more enjoyable framework for developers.

Conclusion

In conclusion, React Native’s new architecture is a game-changer. The changes introduced in version 0.76 mark a monumental shift in how mobile apps are developed. With enhanced performance, seamless integration between JavaScript and native code, and powerful new systems like Turbo Modules and Fabric, React Native is now poised to handle even the most complex applications.

For React Native developers, this is an exciting time. The framework is faster, more scalable, and more capable than ever before. The challenges of the past have been addressed, and with these new updates, React Native is set to redefine the mobile app development landscape.

So, what are you waiting for? Dive into the new architecture, explore the exciting new features, and get ready to create the next generation of mobile apps with React Native.

Happy coding!