React.Suspense and React.Lazy for Lazy Loading Components

Jan 18, 2020

Introduction to React.Suspense and React.Lazy

CTIP The Council for Trade and Investment Promotion welcomes you to explore the powerful optimization techniques for building efficient ReactJS applications. In this guide, we will dive deep into the world of React.Suspense and React.Lazy, two essential features that enable lazy loading of components. By using these techniques, you will significantly enhance website performance and provide a seamless user experience.

What is React.Suspense?

React.Suspense is a mechanism introduced in ReactJS for handling asynchronous rendering. It allows components to suspend rendering while waiting for asynchronous data to be fetched, making it ideal for lazy loading scenarios. By suspending rendering, the browser can avoid unnecessary delays and improve page load times.

How to use React.Suspense?

Using React.Suspense is straightforward. Simply wrap the components you want to lazy load with the Suspense component and specify a fallback UI that is shown while the lazy-loaded component is being loaded. React.Suspense enables you to remove the need for conditional rendering and loading states, simplifying your codebase.

What is React.Lazy?

React.Lazy is a mechanism that allows you to lazily load components in ReactJS. It enables you to split your code into smaller chunks and load them only when needed, reducing the initial bundle size and improving performance. Lazy loading is particularly beneficial for large applications with multiple components.

How to use React.Lazy?

Using React.Lazy is quite straightforward. Simply wrap the dynamic import of your component with React.lazy and provide the path to the component's module. React.Lazy returns a new component that renders the lazy-loaded component when it's needed. Just like with React.Suspense, you can specify a fallback UI to be shown while the component is being loaded.

Implementing Lazy Loading with React.Suspense and React.Lazy

Now let's go through a step-by-step guide on how to implement lazy loading using React.Suspense and React.Lazy:

  1. Install necessary dependencies

    Make sure you have the latest version of React and React DOM installed. You can install them by running the following command:

    npm install react react-dom
  2. Identify components for lazy loading

    Identify the components in your application that can benefit from lazy loading. Typically, these are components that are not immediately required during the initial render of your application.

  3. Create separate files for lazy-loaded components

    Create separate files for each lazy-loaded component. This will allow the bundler to split the code and load the component separately when needed. Make sure to use the dynamic import syntax to import the component:

    const LazyComponent = React.lazy(() => import('./path/to/component'));
  4. Wrap lazy-loaded components with React.Suspense

    Wrap the lazy-loaded components with the React.Suspense component and provide a fallback UI. This UI will be shown while the component is being loaded:

    {` `}
  5. Build and test your application

    Build your application using the bundler of your choice, such as webpack or Parcel. Make sure to test your application thoroughly to ensure the lazy-loaded components are loaded correctly when needed.

Benefits of React.Suspense and React.Lazy

Implementing lazy loading using React.Suspense and React.Lazy offers several benefits:

  • Improved Performance: Lazy loading components reduces the initial bundle size, allowing the browser to load and render your application faster. This results in improved overall performance and better user experience.
  • Better Resource Management: By loading components only when needed, you can optimize the resource allocation of your application. This ensures that resources are used efficiently, improving scalability.
  • Code Splitting: React.Lazy enables you to split your code into smaller chunks, making it easier to manage and maintain your application. It helps reduce complexity and enhances developer productivity.
  • Seamless User Experience: With lazy loading, your application can display essential content immediately while loading additional components in the background. This provides users with a seamless and uninterrupted browsing experience.


In this guide, we explored the powerful optimization techniques of React.Suspense and React.Lazy. By utilizing these features, you can significantly improve website performance, enhance user experience, and optimize resource allocation. Lazy loading components using React.Suspense and React.Lazy is a best practice in modern web development, allowing you to build efficient, scalable, and high-performing ReactJS applications.

CTIP The Council for Trade and Investment Promotion encourages you to implement these techniques in your projects and stay ahead in the competitive web development landscape. Take advantage of the benefits offered by React.Suspense and React.Lazy and unlock the full potential of ReactJS!

Harry Dhanjal
Thanks for the clear explanation! Really helps with lazy loading.
Nov 8, 2023
Laura Ellis
Great explanation! Makes lazy loading components much easier to understand.
Oct 18, 2023
Really helpful guide! Explains React.Suspense and React.Lazy perfectly.
Oct 7, 2023