All You Need to Know About React 18: New Features and Improvements

React 18 is now the most talked-about subject and trend in JavaScript. After much anticipation, the React team has finally released React v18.0, which includes the highly-anticipated concurrent rendering features.

In this article, we will talk about React 18, its new features, and the changes that are done from react 17 to react 18. 

What is React JS?

React is a JavaScript library that builds fast and interactive mobile and web applications. It is an open-source, reusable component-based front-end library of JavaScript. 

React is a combination of HTML and JavaScript. It provides a robust and opinionated way to build modern applications.

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React 18 New Features 

  • Concurrent Features
  • Transitions           
  • Suspense on the server

React 18 Improvements

  • Automatic Batching
  • Better Rendering
  • Performance 

React was released in March 2022

We can install it with the help of npm or yarn


img: command using npm 


img: command using yarn

What’s New in React 18?

In React 18, application concurrency is given more consideration.

This concept comprises APIs such as createRoot, hydrateRoot, renderToPipeableStream, and renderToReadableStream, as well as functions like Automatic Batching, Transition, and Suspense. Along with changes on Strict Mode and the deprecation of ReactDOM, it also provides hooks like useId, useTransition, useDeferredValue, useSyncExternalStore, and useInsertionEffect. render as well as renderToString,

Now we will discuss these concepts 

Automatic Batching 

All state modifications made using event handlers are grouped together using React's built-in batching functionality. It prevents the files from going through a pointless rendering procedure. React 18 also features a modified version of batching called React 18 Automatic Batching that groups all state modifications made by createRoot together.

The process uses timeout and interval functions, asynchronous applications, event handlers, and batch state changes; the background of the updates is not required.


So automatic batching is nothing but to do all the microtask together at the end of the task to save time.

Let me show you an example of automatic batching. 

Earlier, the program used to render in each step but now, with automatic rendering. 

This will only render at the end of the task.


In order to distinguish between urgent and non-urgent updates, React has introduced a new concept called transition.

  • Transition updates move the user interface (UI) from one view to another.
  • Urgent updates reflect direct input, such as typing, clicking, pressing, etc.

So let me give you an example: if you are doing a task and another urgent task comes in that has a higher priority, react will stop that task and work on the higher priority task and then start that task again.



Before react 18 was introduced, if one component of an app was slow, it slowed down the entire app, but with react 18, if one component is slow, it will not slow down the entire App. Suspense allows you to instruct React to send HTML for other components, such as a loading spinner, before sending HTML for the placeholder. The server renderer will then insert its HTML into the same stream once the slow component is prepared and has fetched its data.

React suspense is a feature that enables developers to monitor the rendering elements while the process is still in progress. It then displays its fallback functionality. This functionality can be used in conjunction with the transition API with the most recent React version. It even pauses the rendering schedule to lessen the effect of loading by preventing the content from being changed.

The react suspense is quite helpful since it provides a calm loading state while the user is dealing with a network conflict.


Since React 18 comes with Suspense, it allows us to designate fallbacks for UI elements that are yet to be seen on the screen. Therefore, using the <Suspense> tags, we could wrap a single slow component and delay the component loading. Also, you can configure a fallback to show a loading animation.

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Concurrency in React

React can interrupt, pause, restart, or quit a render in React 18 with concurrent rendering. This enables React to react rapidly to user input while engaged in a time-consuming rendering operation.

The foundation of concurrent rendering is introduced in React 18, along with new features like suspense, streaming server rendering, and transitions.

As a React developer, you concentrate on how you want the user experience to be delivered, and React takes care of the technical details. 

Concurrent React is a foundational improvement to the fundamental rendering model of React, making it more significant than a normal implementation detail. Therefore, even while understanding concurrency's workings isn't crucial, having a general understanding of it could be useful.

Now we can just say where we wanna add the concurrency. Now you can pick where you want this feature to be enabled.

Another example can be:

Concurrent React can remove UI elements from the screen and add them later while restoring the previous state. React should be able to restore the previous screen in the same state it was in before, for instance, when a user tabs away from one screen and comes back to it. We intend to provide a new component named "Offscreen" in a future minor that follows this pattern. Offscreen can also be used to create new user interface elements in the background so that they are ready before the user reveals them.

Strict Mood 

When using React 18's strict mode component will be mounted, unmounted, and then remounted with a previous state. By remounting trees using the same component state before unmounting, React will be able to instantly mount a previous screen in the future thanks to the reusable state.

Strict mode will guarantee that components are resistant to effects being repeatedly mounted and unmounted.

Now we will see the changes done on the client, server, and library sides API’s. 

Client-Side API Changes

1. Render is now become createRoot in react 18 


2. UnmountComponentAtNode is now converted into root.unmount.



3. React.DOM.Hydrate is now converted into hydrateRoot.


Library Side API changes 

  • useId
  • useSyncExternalStore
  • useInsertionEffect

Server Side API changes 

  • renderToPipableStream ( node env)
  • renderToReadableStream ( edge env) 
  • renderToString is now deprecated.

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Benefits of React 18 over React 17

Even after studying how React 17 and React 18 differ, you can still be undecided about whether to use React 18 instead of React 17.

If a new edition doesn't offer greater advantages over earlier iterations, it won't be welcomed.

One of the key benefits of React 18 is concurrency. The ability for React apps running on React 18 and higher to improve their performance on client devices is a brand-new idea, not a feature.

Next Steps

We hope that this tutorial on "React 18 new features and updates" has helped you better grasp how React works. Simplilearn's React JS Training Course will teach you the fundamentals of React, including JSX, props, state, and events, a popular online framework for creating user interfaces. Reducers, actions, and the state tree are all covered in this Redux training course.

If you are looking to enhance your skills further, we highly recommend you check Simplilearn’s Full Stack Java Developer Career Bootcamp. This can help you hone the right skills and prepare you to clear job interviews with ease in no time.

If you have any questions or doubts, please feel free to share them in the comments section below. Our team will get back to you at the earliest.

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Simplilearn is one of the world’s leading providers of online training for Digital Marketing, Cloud Computing, Project Management, Data Science, IT, Software Development, and many other emerging technologies.

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