What is code splitting in React

1. What is code splitting in React?

2. What is code splitting in React? • Code-Splitting is a feature supported by bundlers like Webpack, Rollup, and Browserify. So, in this article, we will see what is code splitting in React. • As websites grow larger and go deeper into components, it becomes heavier. Therefore, code Splitting is a method that helps to generate bundles that can run dynamically. It also helps to make the code efficient. Because the bundle contains all required imports and files.

3. Bundling and its efficiency: • Bundling is the method to combine imported files with a single file. Moreover, it is done with the help of Webpack, Rollup, Browserify. Also, with the help of code splitting, ‘lazy load’ can be implemented. It means just using the code which is currently needed. • The default way of importing as follows: import { add } from './math'; console.log(add(x, y)); // Here x, y are two numbers

4. import("./math").then(math => { console.log(math.add(x, y)); }); // Here x, y are two numbers • Using code-splitting this can be done as follows: As soon as Webpack gets this type of syntax, code-splitting is started automatically. And when using the Create React App, it is already set up and can be used immediately.

5. React.lazy and Suspense: • React.lazy is helpful for rendering dynamic import as a regular component. • Before: import Component from './Component'; • After: const Component = React.lazy(() => import('./Component'));

6. The Bundle will be loaded on its own which contains the Component when this component is rendered first. So, the Lazy component should then be rendered inside Suspense Component. It will help to reflect some fallback content meanwhile the lazy component loads. import React, { Suspense } from 'react'; const Component = React.lazy(() => import('./Component')); function MyComponent() { return ( <div> <Suspense fallback={<div>Loading...</div>}> </div>); }

7. The fallback prop can accept any React item that is processed while waiting for the component to load. So, Suspension components can be placed anywhere above inert components. In addition, a suspension component can be used to wrap various inert components. import React, { Suspense } from 'react'; const ComponentOne = React.lazy(() => import('./ComponentOne')); const ComponentTwo = React.lazy(() => import('./ComponentTwo')); function MyComponent() { return ( <div><Suspense fallback={<div>Loading...</div>}></div>); }

8. But when some modules cannot be loaded due to some problem, an error will be triggered. So, using the proper error pages, these errors can be handled correctly. It will provide users with a good experience. import React, { Suspense } from 'react'; import ErrorBoundary from './ErrorBoundary'; const ComponentOne = React.lazy(() => import('./ComponentOne')); const ComponentTwo = React.lazy(() => import('./ComponentTwo')); const MyComponent = () => ( <div> <Suspense fallback={<div>Loading...</div>}> </div> );

9. import React from 'react'; import Suspense from 'react'; import lazy from 'react'; import {Route, Switch, BrowserRouter } from 'react-router-dom'; const HomePage = lazy(() => import('./routes/HomePage')); const AboutUs = lazy(() => import('./routes/AboutUs')); const App = () => (<Suspense fallback={<div>Loading...</div>}> ); • It can be difficult to implement code-splitting in code. So, the bundles can be split evenly, improving the experience for the user.

10. Also, React.lazy supports only default exports. Also an intermediate module that re-exports as default has to be created if you want to import a module. Moreover, this ensures the working of tree shaking and prevents the pulling in of unused components. // Components.js export const Component = /* ... */; export const MyUnusedComponent = /* ... */; // Component.js export { Component as default } from "./Components.js"; // MyApp.js import {React, lazy} from 'react'; const Component = lazy(() => import("./Component.js"));

11. Conclusion: • So, in this article, we have been through what is code splitting in React. Also, feel free to comment with your suggestions and feedback. Moreover, at BOSC Tech Labs, we have a team of highly experienced React JS developers. They can assist you in developing your customized web app. So contact us to hire experienced React JS developers.