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[EN] Scaling React Performance: From Basic to Advanced Code-Splitting Techniques
[ES] Escalando el Rendimiento de React: De Técnicas Básicas a Avanzadas de División de Código

Scaling React Performance: From Basic to Advanced Code-Splitting Techniques

In this talk, we'll dive into Wix's journey towards achieving unmatched web performance through advanced code-splitting techniques in React, tackling the significant challenges posed by large JavaScript bundles and excessive main thread usage.

As Wix's application expanded, facing increased complexity and demand, traditional performance optimization methods fell short. This presentation will trace the evolution from basic dynamic imports to sophisticated strategies like React component splitting, server-side logic separation, and the adoption of modern techniques including SSR, Suspense, and React server components. Emphasizing the necessity for scalable solutions in large-scale applications, we will also discuss the implementation of the Inversion of Control (IOC) pattern for efficient feature loading.
Importantly, for each solution, I will provide code examples of both the issue and the solution, suitable for both beginners and advanced React developers.

This story not only showcases our significant performance improvement but also highlights the importance of evolving optimization strategies to align with the scale of the application, offering insights into transitioning from simple fixes to advanced, robust solutions for enhancing web application performance in React.

This talk has been presented at React Advanced 2024, check out the latest edition of this React Conference.

FAQ

Dynamic import in React is used by Wix to load React components dynamically after user interaction or conditionally on page load. This method helps in breaking down code into manageable chunks, ensuring efficient loading and rendering of components.

Suspense in dynamic imports helps manage the loading state of components. It provides a fallback UI while waiting for components to load, ensuring a smooth user experience until the component is ready to be rendered.

Yes, code splitting can be used with server-side rendering (SSR) in React. React 18 supports suspense in SSR, allowing components to be conditionally rendered and hydrated only when needed.

Moving JavaScript calculations to the server side reduces the client-side load by performing heavy computations on the server. This approach minimizes the JavaScript needed on the client, enhancing performance and improving user experience.

React 18 introduced server-side rendering support for suspense, allowing Wix to use more sophisticated code splitting strategies. This includes dynamically loading components and calculating props on the server side, improving overall performance.

Code splitting is a technique used to break down JavaScript into smaller chunks or multiple components in React, loading them only when necessary. This ensures users download only the code they need, significantly reducing the JavaScript sent to the client side and improving user experience on Wix websites.

Wix measures website performance using Core Web Vitals, a set of metrics developed by Google, to assess the performance of live websites. Specifically for JavaScript loading, Wix focuses on INP, which evaluates the website's interactivity.

Reducing the amount of JavaScript improves INP scores by minimizing the load on the main thread. This reduces delays in user-triggered events like clicks and hovers, enhancing interactivity and improving INP scores.

Advanced code splitting techniques used by Wix include conditionally loading components on page load, dynamically loading components on scroll or hover interactions, and moving props calculation to the server side.

Gil Eckstein

12 min

28 Oct, 2024

Comments

Video Summary and Transcription

I'm Gil, a performance architect at Wix. Today, I'll explain how we use code splitting to improve website performance. Code splitting breaks down JavaScript into smaller chunks or React components, loading them only when needed. This reduces JavaScript size and improves user experience. We measure performance using Core Web Vitals, focusing on INP scores, which evaluate interactivity. Reducing JavaScript improves INP. Our INP scores have significantly improved, thanks to our code splitting techniques. Let's dive into the code splitting strategies we use, starting with dynamic import and React Lazy. Let's move on to a more advanced example: conditionally loading components on page load, not on user interactions. We fetch the comments data and render the comment section only if there are any comments. This method is supported in React 18 and works for server-side rendering (SSR). React components can be loaded dynamically on scroll or hover interactions with suspense. If the components are already rendered with SSR, we just need to download and hydrate them. This is only possible with the new suspense in server-side rendering (SSR). We use react-lazy with dynamic imports to render the component when it enters the viewport. I created a download on viewport wrapper that creates a ref and uses the intersection observer to resolve a promise when the component enters the viewport. I use the viewport and a wrapper that calls a function called use, which is implemented using the suspense API from React. This function is used to manage the promise and render the components only after it's resolved. The suspense component handles this promise. We moved props calculation to the server side and fetched them in the React component. This approach simplifies the process and can be implemented using the dynamic API in Next.js. By conditionally rendering components and calculating props on the server side, we can significantly reduce the amount of JavaScript code loaded in the client side, resulting in improved performance.

Available in Español: Escalando el Rendimiento de React: De Técnicas Básicas a Avanzadas de División de Código

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