Code-Splitting in React

Code-splitting is a technique that divides a large codebase into smaller chunks, which are then loaded on demand at runtime. This can boost the performance of a React application by reducing the amount of code that the browser must download and parse when the application first loads.

There are several approaches to implementing code splitting in a React application:

Using the import()

The import() function can be used to import a module at runtime dynamically. This will split the module into separate chunks that can be loaded as needed.

Example

Before

import { add } from './math';

console.log(add(16, 26));

After

import("./math").then(math => {
  console.log(math.add(16, 26));
});

Using the React.lazy

You can use React.lazy function to render a dynamic import as a regular component. This makes code splitting in React components simple.

Example

import React, { Suspense, lazy } from 'react';

const SomeComponent = lazy(() => import('./SomeComponent'));

function MyComponent() {
  return (
    <Suspense fallback={<div>Loading...</div>}>
      <SomeComponent />
    </Suspense>
  );
}

This example uses the import() function to dynamically import the SomeComponent component at runtime. The SomeComponent module will be split into a separate chunk, which will be loaded when the component is rendered. While the chunk is being loaded, the Suspense component displays a loading indicator.

Using a code-splitting library

Several libraries, such as loadable-components and react-loadable, can assist you in implementing code splitting in your React application. These libraries offer a higher-level interface for implementing code splitting and frequently include features like automatic loading indicators and error handling.

Example

import Loadable from 'react-loadable';

const SomeComponent = Loadable({
  loader: () => import('./SomeComponent'),
  loading: () => <div>Loading...</div>,
});

function MyComponent() {
  return <SomeComponent />;
}

This example is similar to the previous one, but instead of loadable-components, it employs the react-loadable library. For implementing code splitting in a React application, both libraries provide a similar interface.

Conclusion

Code splitting can help your React application perform better by reducing the initial load time and increasing the time-to-interactive for your users. It’s especially useful for large applications with many components, or for applications with infrequently used features that don’t need to be loaded immediately.

I hope these examples show you how to use a library to implement code splitting in your React app. Please let me know if you have any further questions!