Introduction

Building websites has to be one of the most exciting things in tech. However, the beauty is when users experience seamless interactions while using these websites. Seamless interactions can be achieved when a website is highly performant, unnecessary delays are not experienced during loading times, there are no idle pages, and above all the entire website does not re-render for the smallest interactions.

The process of improving website performance is referred to as Optimization. It might seem like Optimization is a big task to achieve in web development. “This is a big Misconception.”

Web optimization can be achieved by doing the smallest things such as implementing best coding practices.

In this article, we will explore several ways we can improve the performance of React apps by implementing various optimization techniques.

Different Techniques for Optimizing React Apps

Use Functional Components

Using functional components enhances the efficiency of every React app, no matter how simple it may look. Using functional is one of the finest techniques for optimizing React projects, albeit in a subtle way.

Re-usable smaller components

The smaller the better is an essential practice when building react apps to be highly performant. By breaking large blocks of code into small chunks or reusable components, we not only make the code easily readable but also easy to test and scale.

Lazy Loading

When a component is required, this method is used to load it for the first time. This means that components that are not required at the time the initial UI is rendered are not bundled and are only added later.

Suspense boundary

In the easiest way possible, the suspense boundary is used to display a fallback while the page content is been loaded. Another exciting fact about suspense is that it can be nested i.e. a suspense boundary can be used within a parent suspense boundary without breaking the app UI.

React.lazy()

This is used to implement the lazy loading of components only when they are needed. It is used within the suspense boundary so as to display a fallback while it is loading the component.

Dynamic imports

In NextJs (a React framework), Lazyloading is done using dynamic imports from next/dynamic. The process is similar to using the React.lazy function within the suspense boundary in react.

Optimize images

Using large images in your application can be very difficult to load and may consequently slow down the performance of the app. Images can be optimized to improve the performance of apps it can be done in the following ways:

Reducing the size of images

The bigger the size of the image, the longer time it takes to load. In order to reduce delay when loading pages, it is best to reduce images to the smallest size possible. This can be done using compression tools like IloveIMG.

Using the right image format:

There are three file types for photos used in web development.

Although Webp image format is preferable for enhancing web performance and SEO ranking, Jpegs are still used for photographs. GIFs are used for animated images, while PNGs are used for transparent images.

Lazy loading images:
In order to prevent all the images from loading at once into the DOM thereby delaying the time to load for a webpage, we implement lazy loading images. Using libraries like react-lazy and react-lazy-load-image-component, images are only loaded into the dom when they are in the users’ viewport. An example of lazy loading images is shown below:

Memoization:

React.memo is used to prevent re-rendering the entire app when there is no particular change to a component. This means that React will compare the previous render with the current render and if no change is made to the component or its props, it will not be re-rendered.

React.memo is a higher-order component; It is wrapped around a functional component.

Virtualization:

This optimization technique is used in handling long lists or applications with several rows of data. Loading the entire data at once will slow down the performance of the react app, therefore virtualization libraries like react-window or react-virtualized are used to implement windowing.

In virtualization or windowing, only the visible data in the viewport is loaded into the DOM. When the user scrolls, the remaining data replaces the items visible in the viewport.

Another way to achieve virtualization is by paginating data.

Error Boundary

The use of an error boundary is essential in order to prevent even breaks in the app build. When there is any error in your React app, instead of React removing the UI, it displays a fallback UI with an error message. a good example where error boundary proves very effective is indefinite loops. The file below shows the ErrorBoundary.js file.

We can then wrap our components with the error boundary as seen in the code below

Lighthouse performance testing

Chrome's Lighthouse devtool is used to evaluate web pages for speed tests. A report for performance, accessibility, SEO, and other metrics is produced once a study of any given webpage or url is run. This analysis highlights the app's strong points as well as its weaknesses.

Conclusion

In this article, we have discussed various ways by which we can optimize react apps. However, optimization techniques are not limited to what is in this article. By implementing best practices any React app can improve performance. We have also discussed the importance of optimizing react apps. Therefore, you can begin to improve the performance of your applications today.

Happy coding!