7 Methods for Optimizing React Application Performance

Developers are frequently concerned about performance issues when working with a ReactJS application. This unpopular viewpoint has prevented them from gaining the enormous benefits of React technology. However, you will benefit from this cutting-edge front-end technology if you understand why React apps lag in speed as well as how to boost their performance.

This article discusses the seven greatest React app speed optimization approaches for overcoming risks and difficulties.

1. Lazy Loading Images

The speed of your React application is likely to suffer if it contains a large number of images. This happens as a result of the DOM rendering every image before the user interface is shown. Because of this, we recommend using Lazy loading images, which won’t render an image until its turn has arrived on the user’s screen, cutting down initial loading time and enhancing page performance.

Both React-lazyload and React-lazy-load-image-components are popular libraries for lazy loading to increase React performance. We do see many websites that serve a blurred version of an image first, followed by a high-resolution image. This complete interaction is a three-step procedure.

  1. Wait for the content to appear before beginning to import the image
  2. When the image is viewable, a lightweight image with a blur effect is loaded, followed by a request for a high-resolution image
  3. Once the original image is fully loaded, the blurred image gets hidden and the original image will be shown instead

2. React Redux Optimization

An effective and efficient React-Redux application requires a lot of actions. Here are some examples of common optimization techniques,

Use the reselect library – The reselect library helps in the creation of memoized selectors that cache the results of complex calculations. This can increase application speed by reducing unnecessary computations.

Immutable.js – Immutable.js is another tool for improving React Redux app speed. An immutable list performs up to four times better than a mutable list. The original data is not affected while using an immutable data structure, and a new version of the updated data structure is created each time it is required. The speed of the Redux app will decrease when using mutable data structures, as the Redux state tree requires a lot of RAM for copying data. This strategy significantly improves React performance.

Use redux-thunk batch dispatch – By decreasing the number of re-renders, sending multiple actions in a batch can improve performance. To dispatch several actions at once, the redux-thunk library provides a batch dispatch method.

  • Use useSelector from react-redux: useSelector is a hook that prevents unnecessary re-rendering of components that depend on the Redux store
  • Reduce the number of state changes: Reducing the number of state updates can significantly improve the performance of your application. Use useState with functional updates or setState with objects to do this

3. React Memo [Memoization]

React.memo improves functional component performance by reducing re-renders when the props haven’t changed. You can improve performance by wrapping your functional component in React.memo if it produces the same output because it receives the same input props. This means that React will compare the previous render to the current one and skip rendering the component if no differences found. This will improve the React app’s performance.

Note: Please keep in mind that React.memo is not the same as useMemo, because people frequently mix up their names.

4. Use a Function in setState

In the setState method, a function is recommended over an object. This suggestion is provided since state changes aren’t always immediately reflected.

5. Key Coordination for List Rendering

React lists allow you to assign an element with key properties that help in displaying the next list items.

6. Windowing or List Virtualization

Performance problems are common in React apps that render or contain huge lists. Prior to the app launching, the entire list will be shown in the DOM, slowing down the ReactJS app performance and causing UI latency.

List Virtualization or Windowing is one method for overcoming this problem. Instead of rendering an entire list of items on the app window, we restrict DOM to display only the items that are currently visible in the viewport.

7. Trim JavaScript Bundles

Trimming the JavaScript bundle is a technique for minimizing the amount of Javascript code transmitted to the browser, which improves application loading and performance. Javascript bundles can be trimmed in numerous ways,

  • Splitting the Code – Code splitting is the process of breaking code into smaller components and only loading the components that are required for a specific page or functionality
  • Tree Shaking – Tree shaking involves removing unnecessary code from the bundle, ensuring that only the code required by the application is included in the final bundle
  • Minification – The technique of minification reduces code by shortening variable names and deleting whitespace and comments
  • Dead Code Removal – This involves removing code that is unreachable or never executed in the application


Identifying performance issues is an essential step in optimizing the speed of a React Application. By utilizing performance monitoring tools, you can analyze specific areas where you can focus your optimization efforts for better efficiency and user experience. Additionally, tracking performance issues over time by setting up monitoring and logging can help you detect any performance deterioration that might happen in the future.

About the author

Rohit Dasari

Innovative Front End Developer with 2 years of experience in developing and managing responsive web applications. Proficient in HTML, CSS, jQuery, JavaScript, and React, and I'm eager to learn new technologies to widen my knowledge and skills.

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By Rohit Dasari
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