How Do You Use React JS for Lazy Loading?

React is one of the most used flexible libraries for building user interfaces in different industries. But mostly it is used for building single-page applications where the user can interact with the application without needing to reload the page. Well, one of its exciting features is React Suspense which allows a component to fall back to another component at the time of loading.?

In this article, we are going to discuss in detail how to use React JS for lazy loading. So if you are looking to grow your career in this field, you can enroll in the React JS Course. This course will help you understand the basics of React.? So let’s begin understanding React Suspense first.

What is React Suspense?

React Suspense is a feature in React that helps manage the loading state of your components. It "pauses" the rendering of a component until something important, like loading other parts of the app or getting data from a server, is finished. This makes sure your app only shows the content once everything is ready, preventing users from seeing incomplete or broken pages.

How Does React Suspense Work?

React Suspense is a feature that improves the user experience by delaying the rendering of a component until the data it needs is ready. When a component is "suspended," React shows a fallback UI, like a loading spinner, to the user while the component waits for the required data. This helps avoid problems like showing incomplete content during data loading.

If you are looking to understand this more easily, it would be advisable to take React JS Training in Chennai. Because Chennai is a great place with many reputed institutions to learn such skill-based courses. Well to use Suspense, you typically wrap a component with React.lazy(), which makes it lazy-loaded. Inside this lazy-loaded component, you might gather data using methods like fetch or other data-fetching libraries. If the data isn't ready yet, the component will "suspend" its rendering, and the <Suspense> boundary will show the fallback UI instead. Once the data is loaded, the component will resume rendering.

Using Suspense can improve your app's performance by loading only the necessary components upfront and making the experience smoother and more responsive for the user.

React Suspense: The Core Concept

React Suspense makes it easy to implement lazy loading in your React applications. It does this by introducing two key concepts:

React.lazy():?

A function that helps you define a component as lazy-loaded. This means the component won’t be loaded until it’s needed, reducing the initial load time of your app.

<Suspense>:?

A wrapper component that acts as a placeholder while the lazy-loaded component is still loading. It shows a fallback UI (like a loading spinner or a skeleton loader) until the component is ready.

Implementing Lazy Loading with React Suspense

It would be easy to implement lazy loading with React Suspense easy for you if you have gained React Certification. Here’s how you can implement lazy loading using React Suspense:

1. Import Necessary Modules:

javascript

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

2. Define the Lazy-Loaded Component:

You use React.lazy() to load the component lazily. This function takes a dynamic import() statement, which loads the component only when it's needed.

Javascript

const MyComponent = lazy(() => import('./MyComponent'));?

3. Wrap with <Suspense> and Provide Fallback:

You wrap your lazy-loaded component with <Suspense> and use the fallback prop to show a loading UI while the component is being fetched.

javascript

<Suspense fallback={<div>Loading...</div>}>

??<MyComponent />?

</Suspense>

The fallback prop specifies what to display while the component is loading (like a loading spinner or a skeleton loader).

Example:

Here’s a full example of how to use React Suspense with a lazy-loaded component:

javascript

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

// Lazy load the MyComponent

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

function App() {

??return (

????<div>

??????{/* Suspense wrapper shows "Loading..." while MyComponent is loading */}

??????<Suspense fallback={<div>Loading...</div>}>

????????<MyComponent />

??????</Suspense>

????</div>

??);

}

export default App;

Advanced Usage:

There are various uses of React Suspense which we have discussed below.

1. Data Fetching with Suspense:

You can combine lazy loading with data-fetching libraries like React Query, SWR, or Apollo Client. These libraries have built-in support for Suspense, allowing you to manage both data fetching and component loading smoothly in a single flow.

2. Error Handling:

Since loading components or fetching data can fail, it’s a good idea to use Error Boundaries within your Suspense components. This will allow you to catch errors gracefully and show fallback content, improving the user experience.

3. Code Splitting Strategies:

React Suspense works well with code-splitting techniques. You can use dynamic imports or route-based code splitting to load different parts of your app only when they’re needed. This reduces the initial bundle size, making your app load faster.

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Conclusion:

From the above discussion, it can be said that React Suspense is a useful feature that helps make your app faster and more enjoyable to use. It allows you to lazy-load components, which means that parts of your app are only loaded when needed, instead of all at once. By using Suspense to manage loading states, your app can load faster at the start, and users will have a smoother experience while they wait for content to appear.