Code Splitting

What is code splitting and why is it important?

Code splitting is a technique that divides the bundle of an application into smaller, more manageable parts. Instead of sending a single large file to the browser, it is split into several segments, each one loading the necessary parts only when the user requires them. This is essential for large web applications, as it improves performance and reduces load time. Several frameworks such as Angular, Next.js and Gatsby already take advantage of code splitting, automatically dividing the code according to the application paths.

How do the different code splitting strategies work?

Page splitting:
Modern frameworks perform code splitting based on application paths. Each page becomes an independent bundle, so that only the resources strictly necessary for each view are loaded.

Separation of code and dependencies:
Another effective strategy is to split the bundle into two parts: the application code and the external dependencies or libraries, also known as vendors. This allows greater control and optimization in the management of resources, offering more efficient updates and uploads.

How do we use Webpack for code splitting?

Webpack is a powerful tool for managing JavaScript bundles. By implementing code splitting with Webpack, you can significantly optimize project performance. To do this, we need to configure its optimization to split files properly.

Basic steps:

1. Webpack configuration:

   • Access the Webpack configuration file and remove any unneeded code, such as redundant logs.
   • Implement the optimizations for code splitting that Webpack provides.

2. Execution and review:

   • Run the npm run build command to see the results of your code splitting.
   • Check the generated files, which should include the main.bundle.js for the application code and another bundle for the libraries or vendors.

3. Update the HTML:

   • Modify the scripts in your HTML to load the newly generated bundles in the correct order: libraries first, then the main code.

4. Final testing:

   • Run your project to make sure everything works correctly.
   • Use development tools such as the browser's "Network" to verify the correct loading of the bundles.

What are the benefits of code splitting for browsers?

The main advantage of code splitting is its integration with browser caching strategies. External libraries or vendors tend to change little between deployments, so they can be cached by the browser, significantly reducing the number of requests to the server. This optimizes load and improves the user experience, allowing only the core application code to be updated when necessary.

Specific benefits:

• Optimized initial load: Only what is essential for each view is sent to the client.
• Reduced load on the server: Decreases the number of requests thanks to caching.
• Improved user experience: By reducing load times, users get a smoother and faster experience.

By applying these principles effectively, you can maximize the performance of complex applications, offering a more responsive and efficient user experience. We continue to learn and improve on the road to advanced web development!