React Upgrade

Upgrade your React projects for improved performance, new features, and better developer experience. Learn about essential steps and best practices.

Table of Contents

Why Upgrade to React 18? A Look at the Benefits

React 18 is a significant step forward for building dynamic and performant user interfaces. Upgrading your React application to version 18 unlocks many benefits, making it a worthwhile investment for developers. Here’s a closer look at what awaits you:

Exciting New Features

React 18 introduces powerful new features that enhance the developer experience and application capabilities. These include:

  • Automatic Batching
    This optimization technique automatically groups multiple state updates together, leading to smoother and more efficient rendering.
  • Concurrent Rendering
    This feature allows React to work on multiple tasks simultaneously, improving responsiveness for user interactions, especially in data-heavy applications.
  • New Hooks
    React 18 introduces a set of new hooks like useId and useTransition that provide greater flexibility and control over component behavior.

Performance Enhancements

Beyond new features, React 18 delivers significant performance improvements. Automatic batching reduces unnecessary re-renders, leading to a faster and more responsive user experience. Concurrent rendering allows the UI to remain interactive even when fetching or processing data, keeping your application feeling smooth and responsive.

Staying Up-to-Date and Secure

Upgrading to the latest version ensures you benefit from the latest bug fixes and security patches. This helps maintain a stable and secure codebase, reducing the risk of vulnerabilities and unexpected behavior.

Future-Proofing Your Application

Using the latest advancements in React, you ensure your application remains compatible with future tools, libraries, and frameworks. This helps safeguard your development efforts and simplifies integrating new features and functionalities.

Updating React Dependencies with Package Managers

Once you’ve decided to upgrade React, the first step is to update your project’s React and ReactDOM packages. Here’s how to do it using either npm or yarn, the most common package managers for React development:

Using npm

npm install react@latest react-dom@latest


  • Line 1: This command uses npm install to install new packages or update existing ones.
  • react@latest and react-dom@latest: These flags instruct npm to install the latest versions of the react and react-dom packages, respectively.

Using yarn

yarn upgrade react react-dom


  • Line 1: This command uses yarn upgrade to upgrade existing packages within your project.
  • react and react-dom: These arguments specify the packages you want to upgrade.

Important Considerations

  • Upgrading with @latest might not always be the best approach, especially for large projects. Check the official React release notes to understand potential breaking changes before upgrading.
  • Running npm outdated or yarn outdated beforehand can give you an overview of outdated packages in your project.

Remember to update other related React dependencies after upgrading the core react and react-dom packages. This ensures compatibility and avoids potential issues in your application.

New Root API in React 18 (ReactDOM.createRoot vs ReactDOM.render)

React 18 introduces the new Root API centered around the createRoot method. This shift aims to improve code clarity, separation of concerns, and cover future rendering capabilities. Here’s a breakdown of the thinking behind this shift:

  • Improved Readability
    The new API separates creating a root DOM container from the actual rendering of React components, leading to cleaner and more concise code.
  • Flexibility
    createRoot returns a Root object containing information about the root itself. This allows for more granular control over rendering behavior in the future.
  • Future-Proofing
    The new API lays the groundwork for future features like concurrent rendering across multiple roots.

Old Approach (ReactDOM.render)

In React 17 and earlier, the ReactDOM.render method was used to create a root DOM container and render a React component within it.

New Approach (ReactDOM.createRoot)

React 18 introduces ReactDOM.createRoot for creating a root container. This separates the container creation from component rendering, promoting a cleaner approach.

Migrating from Old to New API Example

// Old Approach (React 17)
import React from 'react';
import ReactDOM from 'react-dom';

const container = document.getElementById('root');
ReactDOM.render(<App />, container); // Render the App component

// New Approach (React 18)
import { createRoot } from 'react-dom/client';
import App from './App'; // Assuming App is your component

const container = document.getElementById('root');
const root = createRoot(container); // Create a root object

root.render(<App />); // Render the App component within the root


  • Lines 2-3 (Old Approach): We import React and ReactDOM for component creation and rendering (React 17 style).
  • Line 5 (Old Approach): We obtain a reference to the DOM container element.
  • Line 6 (Old Approach): We use ReactDOM.render to render the App component directly within the container.
  • Lines 9-10 (New Approach): We import createRoot from the updated react-dom/client module (React 18). We also import the App component.
  • Lines 12-13 (New Approach): We get the container element similar to the old approach. Then, we call createRoot(container), which creates a Root object associated with the container.
  • Line 15 (New Approach): We use the render method on the root object to render the App component within the established root container.

While the core functionality remains similar, the new API separates the creation of the root container from the actual rendering. This improves code organization and lays the groundwork for future React features that use the Root object for more granular control.

Best Practices for Upgrading React

Here’s a list of best practices for upgrading React:

  • Start Small: Upgrade minor versions incrementally before tackling major ones.
  • Read the Changelog: Carefully review React’s release notes for potential breaking changes.
  • Update Dependencies: Make sure third-party libraries are compatible with the new React version.
  • Check for Deprecations: Address any deprecated features or syntax in your codebase.
  • Leverage Community Resources: Utilize official documentation, blog posts, and forums for troubleshooting.
  • Gradual Migration: Consider upgrading larger projects component-by-component for a smoother transition.
  • Prepare for Potential Issues: Allocate time and resources to address unexpected compatibility challenges.