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React JS

React 19: What’s New in the Latest Version of React JS v19

Last Updated on July 9, 2024

Summary

The super popular UI library within front-end development, React, is back with the latest version of React JS 19. As we know, since its launch in 2013, the React team, alongside the extensive community working together, never leaves a chance to surprise us with exceptional features and updates. The same is true with this year’s ReactJS 19 latest RC release on 15 May 2024. In this blog post, we will look at what’s new in React 19 features and updates you can leverage for exceptional front-end development in the future.

Introduction

React, or ReactJS is a free and open-source front-end JavaScript UI library that allows the building of user interfaces based on the components. With the release of React 18 last year, the team came up with many features, such as automatic batching, transition API, backward compatibility, and more. However, React 19 launched the beta this year on 25 April 2024 and shifted to the RC version as of 15 May 2024. The team working on the most popular JavaScript library has returned with a bang. Let us look in detail at What’s New in React v19.

What’s New in React 19?

React v19 is significant with its latest features and updates. The React 19 RC is now available on npm. While ensuring optimal performance and efficiency, the latest version of React comes with a set of robust features like Actions, Actual Client and Server Directives, Document Meta Data, Web Components, Suspense Head Loading, ‘use’ API, React Compiler, and more to simplify web development processes and enhance performance. Let us look at those features and see how React JS 19 is revolutionizing front-end development across the globe.

Actions

Actions in ReactJS 19 are similar to those in Next.js, including client and server directives. Within the React JS 19 version, Actions represent a modern approach for handling elements such as forms on your website. They also enable you to seamlessly update your page content upon form submission, eliminating unnecessary intricacies. The said functionality effectively benefits by preserving a smooth and simple user experience.

Actions work seamlessly on both client and server sides, providing stability where it was previously lacking. Alongside this improvement, React.js 19 introduces hooks like useActionState and UseFormState, simplifying state management and loading processes.

Using Actions instead of onSubmit handlers reduces boilerplate code for form handling, error messages, and more. This approach, combined with hooks like UseFormStatus and UseFormState, streamlines form management tasks. Additionally, the new UseOptimisticUpdates hook further enhances React’s form-handling capabilities.

Actions also allow you to incorporate actions with the HTML < form /> tag. You can easily substitute the onSubmit with the actions that function as HTML form attributes.

Before Actions

In the code snippet below, we will use the onSubmit React event to execute the search method upon the form submission. It is important to note that, at this moment, the search method functions solely on the client side. This limitation of the form submission options to React events prevents the execution of the search on the server side.

<form onSubmit={search}>

<input name="query" />

<button type="submit">Search</button>

</form>

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After Actions

The latest version of ReactJS 19 introduced the server components, and Actions gained the ability to execute them on the server side. Instead of using the onSubmit in JSX < form/ >, we can use the action attribute to submit data on either the client or the server side. The Actions handle the synchronous and asynchronous operations, simplifying the data submission and state updates for streamlined form handling and data management. Let us take a look at the examples below.

"use server"

const submitData = async (userData) => {

const newUser = {

username: userData.get('username'),

email: userData.get('email')

}

console.log(newUser)

}

const Form = () => {

return <form action={submitData}>

<div>

<label>Name</label>

<input type="text" name='username'/>

</div>

<div>

<label>Name</label>

<input type="text" name="email" />

</div>

<button type='submit'>Submit</button>

</form>

}

export default Form;

In the below snippet, submitData is the server component’s action. Meanwhile, the form component resides on the client side and uses submitData as its action. The setup allows submitData to execute on the server. The action attribute facilitates the interaction between the client (form) and the server (submitData) components.

Actual Client And Server Directives

In Next.js, you can check whether code is running on the server or the client by using the client or server context at the beginning of a file. This distinction is straightforward and helps you know where the code will execute. With the stable release of React-19, other frameworks can leverage its features, leading to the development of more frameworks beyond Next.js. This expansion promises a wealth of new features and opportunities for innovation across different frameworks.

Learn More: React JS Q&A

Document Meta Data section

React v19 offers another new feature in React 19 called < DocumentHead > that helps add titles and meta tags to webpages easily. If you wish to have different titles on multiple pages, you can drop this component, and it will be done. It helps improve SEO practices and maintains brand consistency without duplicating code. This feature simplifies managing metadata in React apps, especially for server rendering, overcoming limitations of libraries like React Helmet.

Web Components

Web components are like special building blocks you can make for websites using basic tools like HTML, CSS, and JavaScript. They blend in seamlessly with regular HTML tags on your web pages. Now, React.js 19 has improved web components. Usually, using web components in React can be tricky because you either have to change them to fit React’s style or use extra stuff to make them work together. But ReactJS 19 is here to make things easier. Now, you can use web components in your React projects without the extra fuss. This opens up many cool options for combining React with other useful web components, like carousels, without changing them into React code.

This update makes developing in React smoother and lets you tap into many ready-made web components for your projects.

Suspense Head Loading (Asset Loading)

It is a new feature in the Reactv19 version update, a new capability in React 18, enabling streamlining content and data rendering, similar to the way it is done in NextJS. It also ensures that certain elements like are fully loaded before displaying the page. It prevents rendering issues where the page needs to be without necessary CSS or scripts being downloaded. It also offers simple APIs for managing more than just styles, links, and scripts based on the requirements.

ReactJS 19 has also introduced new Resource Loading APIs, like preload and preinit , which give better control over when resources load and start up. This update lets assets load in the background, cutting wait times and ensuring smooth user interaction. It also improves React app performance and enhances users’ browsing experience.

forwardRef (Not Needed Anymore)

The forwardRef function in React passes a ref through a component to one of its children. Typically, when you create a custom React component, it doesn’t automatically receive a ref that can be used to access its underlying DOM element or component instance. However, forwardRef can forward the ref from a parent component to a specific element or component inside your custom component

With the React 19 version update, you will not have to use the forwardRef again. The ref prop you get using the forwardRef will be automatically passed to every component inside React. Therefore, you can use it by passing it along as a second prop. To better understand it, let us refer to some code.

Before:

import React, { forwardRef, useRef } from 'react';

const InputText = forwardRef((props, ref) => <input ref={ref} {...props} />);

export default function App() {
  const ref = useRef();

  return (
    <div>
      <InputText ref={ref} placeholder="focus on click" />
      <button onClick={() => ref.current.focus()}>Focus</button>
    </div>
  );
}
}

After:

import React, { useRef } from 'react';

const InputText = (props) => <input {...props} />;

export default function App() {
  const ref = useRef();

  return (
    <div>
      <InputText ref={ref} placeholder="focus on click" />
      <button onClick={() => ref.current.focus()}>Focus</button>
    </div>
  );
}
}

This code signifies that ‘forwardRef’ is no longer needed, as the ‘ref’ is treated as a regular prop. The change simplified the code and eliminated the need for extra effort.

‘use’ API

React JS 19 has introduced an experimental API called ‘use’, which aims at simplifying the handling of the resources such as Promises or context directly within the render function. This API allows for cleaner and more concise code, enabling the development teams to access the resource values without needing separate state variables or lifecycle methods. Primarily focused on data fetching, ‘use’ makes managing the asynchronous data in React components easy.

Though currently, it is available only in React Canary and experimental channels, ‘use’ is still under development and may undergo changes before the stable release. It also has a few limitations, such as:

‘use’ API can only be called inside a component or a hook to ensure proper rendering behavior and prevent unexpected side effects.
When using the ‘use’ API in Server components, you must use ‘async’ and ‘await’ for data fetching as ‘use’ re-renders the components after the resource resolves while the ‘async’ and ‘await’ resume rendering from the point of invocation.

Also Read: Best React JS Tutorials

React Compiler

With React 19 RC, the React development team also announced React Compiler, a significant advancement for the React ecosystem and no longer a research project. It makes React code run much faster by turning it into plain JavaScript. This means your application’s startup performance is improved by almost twice as fast. It also changes how React handles components in the background. Now, React has figured out when to update the state and refresh the interface. This saves developers from having to step in manually. As a result, you won’t need to use certain functions like useMemo(), useCallback(), and memo anymore. The compiler is working on Instagram and will soon be available on other Meta platforms. Eventually, it will be available as open-source software.

Other ReactJS 19 RC Features and Updates

Improved error reporting for hydration errors in react-dom
Ability to render async scripts anywhere in a component tree for better support
APIs for loading and preloading browser resources to optimize resource loading
Enhanced handling of third-party scripts and browser extensions in the hydration system
Improved error handling with reduced redundancy and more options for handling mistakes
Support for native rendering of document metadata tags in components
‘ref’ callbacks can now return functions for cleanup
Addition of an initialValue option for useDeferredValue for better control
‘ref’ as a prop
Custom Elements support

Refer to the official documentation for a detailed understanding of the React 19 RC.

Conclusion

With this, we can conclude that the development team working on ReactJS version 19 has brought about significant changes in the latest versions of React. We hope this addresses the query of what’s new in React 19 features and updates. Depending on your needs and requirements, you can upgrade your existing project to ReactJS 19 and get the most out of your business application development. However, as a business owner, if you are confused about how you should upgrade to the latest React version 19, get in touch with a leading React JS development company like Bacancy and focus on your business. At the same time, we strive to get the best out of your business application development.