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Supermarket Belongs to the Community

Supermarket belongs to the community. While Chef has the responsibility to keep it running and be stewards of its functionality, what it does and how it works is driven by the community. The chef/supermarket repository will continue to be where development of the Supermarket application takes place. Come be part of shaping the direction of Supermarket by opening issues and pull requests or by joining us on the Chef Mailing List.

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React Code Splitting: Best Practices for Optimal Performance DSC Resource

In this comprehensive blog, we will explore the best practices for implementing code splitting in React applications to achieve optimal performance and enhance the user experience.

Install & Usage Instructions

React's popularity as a powerful front-end library lies in its ability to create rich and interactive user interfaces. However, as applications grow in complexity, they can become bulky, leading to slower load times and reduced performance. This is where code splitting comes into play. Code splitting is a technique that allows developers to split the application's code into smaller, more manageable chunks, loading only what is necessary for each specific page or feature. In this comprehensive blog, we will explore the best practices for implementing code splitting in React applications to achieve optimal performance and enhance the user experience.

Importance of Code Splitting

As modern web applications grow in size and complexity, the initial loading time can become a critical factor that impacts user experience. Code splitting allows developers to divide the application's JavaScript bundle into smaller, more manageable chunks. By loading only the necessary code for each specific page or feature, code splitting reduces the initial payload, leading to faster loading times and improved performance.

How Code Splitting Works?

To help readers understand the technical aspects of code splitting, we delve into the inner workings of modern JavaScript bundlers like Webpack. We explain how code splitting is achieved through dynamic imports, which enable the loading of specific modules or components only when they are needed. This contrasts with traditional static imports, where the entire application's code is bundled together and loaded upfront.

Implementing Code Splitting in React

Leveraging Dynamic Imports: Guide developers on how to implement code splitting React applications using dynamic imports. We demonstrate how to set up dynamic imports using the import() function, which returns a promise that resolves to the module or component being imported. This enables lazy loading of components, loading them asynchronously only when required.

React.lazy and Suspense: React provides built-in support for code splitting through the React.lazy function and the Suspense component. We explain how to use React.lazy to lazily load components and wrap the lazy-loaded components with Suspense. The Suspense component allows developers to define fallback UIs or loading indicators to display while the dynamic import is in progress. This ensures a smooth user experience during the loading process.

Error Handling with Suspense: Addressing error scenarios is crucial when implementing React code splitting. We explain how to handle errors during dynamic imports using React Error Boundary components and fallback props provided by Suspense. Proper error handling ensures that the application remains stable and provides meaningful feedback to users when dynamic imports fail.

Combining React.lazy with React Router: Integrating code splitting with React Router is a common use case. We guide readers on how to combine React.lazy with React Router to dynamically load components for different routes. This enables developers to optimize loading times by loading only the required components for each route, improving the overall application's performance.

Setting a Default Fallback: To enhance the user experience further, developers can set a default fallback to display while any lazy-loaded component is loading. This default fallback can be a loading spinner or a skeleton UI that provides visual feedback to users during the loading process.

By elaborating on these sections, readers will gain a thorough understanding of code splitting in React applications and how to implement it effectively using dynamic imports and React's built-in features like React.lazy and Suspense. They will be equipped with the knowledge and tools to optimize their React applications' loading times, improve performance, and deliver seamless user experiences.

Code Splitting Best Practices

Code splitting is a powerful technique for optimizing the performance of React applications, but it requires careful consideration and implementation to achieve the desired results. In this section, we explore some best practices for code splitting to ensure optimal performance and user experience.

Optimal Chunk Size: Determining the optimal size of code chunks is crucial for achieving the right balance between loading speed and the number of requests. While smaller chunks lead to faster loading times, having too many small chunks can result in a higher number of HTTP requests, which may affect performance. Developers should aim for reasonably sized chunks that allow critical parts of the application to load quickly while minimizing the number of requests.

Route-Based Code Splitting: Implementing code splitting based on routes is an effective strategy for loading only the necessary components for each route. Developers can create separate chunks for different routes, enabling users to access specific functionality without loading the entire application upfront. Route-based code splitting significantly improves the perceived loading speed and helps users engage with the application faster.

Prioritizing Critical Code: Prioritize loading critical code first to enhance the application's perceived performance. Critical code includes the main entry point of the application, essential UI components, and user interactions necessary for initial engagement. By loading critical code first, developers ensure that users can start interacting with the application quickly, even if non-essential code is still loading.

Caching and Memoization: Take advantage of browser caching and memoization to optimize subsequent loads. When users revisit the application or navigate to different parts of it, cached chunks can be reused, reducing loading times and providing a smoother experience. Developers can configure caching settings in the Webpack configuration to control the lifespan of cached chunks.

Testing and Monitoring Performance: Regularly test and monitor the performance of code splitting configurations to identify areas for improvement. Developers can use tools like Lighthouse, Google PageSpeed Insights, or Chrome DevTools to measure loading times and assess the impact of code splitting on the overall performance. Continuously optimizing code splitting based on real performance data ensures the application remains responsive and efficient.

Critical CSS and Inline Scripts: Consider inlining critical CSS and scripts to improve the initial rendering time. Inlining essential styles and scripts directly in the HTML can eliminate the need for additional requests and reduce the time to first render. This technique is especially useful for delivering a fast initial view of the application to users.

Conditional Loading: Use conditional loading to load components or features only when they are needed. Conditional loading allows developers to load specific code based on user interactions or application states. This strategy helps reduce the initial payload and allows the application to load progressively as users interact with it.

Avoiding Over-Splitting: Be cautious about over-splitting the application, which can lead to an increased number of HTTP requests and affect performance negatively. Strive for a balance between code splitting to reduce initial loading times and the potential overhead of additional requests.

Progressive Loading and Prefetching: Consider implementing progressive loading and prefetching for non-critical components or features. Progressive loading delivers essential functionality first, while prefetching non-critical components in the background, reducing latency when users navigate to other sections of the application.

A/B Testing Code Splitting Configurations: Experiment with different code splitting configurations using A/B testing to determine the most effective setup for the target audience. A/B testing helps developers make data-driven decisions on code splitting strategies that deliver the best performance and user experience.

By following these React code splitting best practices, developers can create React applications that load efficiently, provide a seamless user experience, and maintain optimal performance across various devices and network conditions. Code splitting, when combined with other performance optimization techniques, ensures that React applications deliver a responsive and delightful experience to users, contributing to increased user engagement and overall satisfaction.


In conclusion, code splitting is a powerful technique that plays a significant role in optimizing the performance of React applications. By following best practices and implementing dynamic imports with React.lazy and Suspense, developers can significantly reduce initial loading times and enhance user experiences. Splitting routes and components, preloading critical code, and prefetching non-critical code further optimize application performance.

Monitoring performance metrics and measuring code splitting impact helps developers fine-tune configurations for optimal results. As React applications continue to grow in complexity, code splitting remains a valuable tool to maintain responsiveness and ensure a smooth user experience.

By adhering to code splitting best practices, developers can create React applications that load efficiently, delight users, and deliver exceptional performance. Code splitting, along with other optimization techniques, ensures that React applications remain competitive, delivering superior user experiences in the modern web landscape. Embracing code splitting best practices and seeking expert guidance from CronJ enables hire react.js developers to navigate the challenges of React development successfully.