What’s new in React 18?

June 30, 2022


What is React?

React is an independent and open-source front-end JavaScript library for building user interfaces.The current version of React 18 provides developers with improved features to create a Great User Experience. Some of the improvements are

  • Automatic Batching: Groups all state updates which in turn improves performance.
  • Transitions: Is now more sophisticated and differentiates between urgent and non-urgent user interactions.
  • React Suspense: Allows for better Server-side rendering and improves the User Experience. as well as Performance

Let’s look at these in a bit more detail

  1. Automatic Batching:

    Batching is one of the React features that combines all the updated states in a single update. Batched updates can be performed inside React event handlers, i.e., it only worked inside the synchronous React event handlers functions. These changes were made in React version 18 with automatic batching.In the example code below, it shows how the automatic batching helps to stop re-rendering the set Counter () function twice.

  2. Transitions:

    Transition is an advanced concept introduced in React 18 that helps to differentiate between urgent and non-urgent updates.

    • Urgent Update: It reflects direct interaction like typing, clicking, pressing etc. This visual feedback is high priority for users.
    • Non-urgent Update: Non-urgent updates are not vital to the user like searching, which can be marked as no-urgent updates.

    For such use cases, startTransitions and useTransitions methods are used.

    • useTransitions: useTransitions is a hook concept that begins transitions, in addition to a value to track the pending state.
    • startTransitions: startTransitions is a method to initialize start transition where hooks can’t be used. Below is the example for startTransition where you can put your code which is non-vital to the end user.
  3. Suspense:

    Suspense lets you declaratively specify the loading state for some of the component tree if it’s not prepared to be displayed. Suspense in React version 18 functions better when combined with transitions API. while you suspend the time of transition, React will halt already-visible content from being altered by a fallback. Rather, React will stop or delay the rendering until enough data has loaded to prevent an inferior loading state.
    Below is the example for Suspense that explains how to use a fallback property of it to show the loading state to the end-user.


    Concurrency is the most important addition in React version 18. It is a confidential mechanism that makes it possible for React to prepare multiple versions of UI.

    For these, React uses a “dispatcher” internally which is responsible to compile and combine the callbacks.

    Before React 18, the user did not have any way to control the appeal order of these functions. Since the release of React version 18, React is providing some authority to this event loop to the user with a Transition API.

    How to upgrade to React version 18?

    You will need to install React 18 and DOM using npm/yarn.

    npm install react react-dom

    npm install react@latest react-dom@latest

    After upgrading to version 18, the following changes need to be made in the Index.js file:

    Note: – There is an error in the console while upgrading to version 18.

    To fix this console issue, the index.js is converted to the latest React version 18, which recommends a new root API. This new root API provides a user-friendly system for executing roots. The new root API also enables the new concurrent re-renders which fastens the coexisting features.

    Our React developers have experience of building complex applications using React technology. They use the latest Dev tools such as React-Redux, React Hooks, React Router, React Bootstrap etc. If you would like to develop a mobile or web application using React technology, then please feel free to contact us.

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