React v18.0

What is New in React v18.0?

The new version release of React, v18.0 took place in March 2022. There is a tonne of exciting new features included. Our team, as a part of a top ReactJS development company, is enthusiastic about this update. New React versions frequently spark debate, and this version is no exception. But in terms of features, this edition has shown to be quite rich in original concepts. The best front-end library is praised for its unwavering dedication to innovation and improvement. This could be a valid reason for you to hire ReactJS app developer for your projects. React 18 doesn’t let us down on that front. Additionally, React’s main goal has always been to enhance performance. The biggest speed improvements in React 18 can be seen in its new features. The rendering engine has received a lot of attention in particular.

Without further preamble, let’s jump right into the details of all the new features in React version 18.0.

New Features in React 18: an Overview

React 18 is enriched with a huge number of new improvements based on the new features and basic improvements to rendering models. React Labs has indeed been developing several ground-breaking modifications for the library. React v18.0 includes many exciting innovative features as a result.

Concurrent React, as well as Suspense, are the most exciting among these, and they are also the most intriguing. Concerning both of them, we would discuss them in considerable detail.

Concerning both of them, we would discuss them in considerable detail.  First off, Automatic Batching along with Transitions are the two biggest improvements in this edition. Suspense, as well as Concurrent both, have some improvements to their integration. Several extra hooks were also added for convenience in adoption.

Although it is currently being built, we will also discuss server components in this article. It is receiving minor changes to enable greater usage. Third-party users and the efficient integration of this release have received great priority in React 18. As we explore the various features added in this edition, we will come across numerous examples of this, such as the hooks I briefly discussed above.

Concurrent React

Let’s start by defining concurrency. In terms of programming, what does concurrency mean? Concurrency is the capacity to execute multiple programs or numerous elements of a program at once.

The new Concurrent React feature in React version 18.0 aims to fundamentally alter how we handle concurrency.

According to the React Team, Concurrent React can not merely be called an update. They’re calling it an “implementation detail” that makes place for more recent modifications, and quite properly so. As a front-end developer, you presumably are not particularly interested in implementation details. You are probably going to concern yourself with “what” than “how” components enter your user interface. Concurrent React seems almost like a fundamental update to React’s primary rendering paradigm in this regard, hence it is still relevant to discuss in this context.

How does Concurrent React improve the quality of our applications? The primary benefit of concurrent react is the ability to interrupt rendering. Although we usually equate interruption with being undesirable, in this case, it offers a significant utility. Being interruptible implies that React is now capable of the beginning, pausing, and continuing during rendering an update. It might even opt not to keep working on an already-running render. How does that aid us? React can ensure that the user experience will continue to seem consistent even if a render stops thanks to this. Concurrent React, in other terms, enhances our apps by enabling React to prioritize components. Let’s delve a little more into this.

Delaying DOM updates after a thorough tree examination is accomplished by this. React may now create new displays in the process without pausing the main thread as a result. It improves the user interface by allowing it to adapt to input from people as it is rendering. Utilizing concurrent React also makes it possible to remove UI elements of the UI and add them later by reusing the prior state.

As I already indicated, practically every new version of React will attempt to facilitate the transition from the previous version smooth. The current focus for React Concurrent is also on a gradual transfer of more conventional react functionalities to combine with concurrent. We have enough space to implement Concurrent progressively in our programs. By utilizing <StrictMode>, you can optionally implement Concurrent on specific portions of your program.

Suspense

React 18 brought the long-awaited addition of the much-wanted suspense function. The Suspense feature was only partially implemented in earlier versions of React because the React Lab intended to test it out first before making it available as a full feature. The suspense will receive more changes in the next minor React 18 version upgrades.

What is Suspense’s purpose? Suspense can now fetch data from opinionated frameworks like Next.js Relay, Remix, or Hydrogen with React version 18.0. It is critical to emphasize that even while it is technically feasible, using Suspense for global data fetching is not yet recommended. Suspense has been eagerly anticipated because obtaining data from many other frameworks and libraries is crucial to creating an effective application. It gives programmers a great deal of flexibility as well as adaptability. The process of integrating from other frameworks is simple by using Suspense. It makes sense why we are so enthusiastic about it!

It is anticipated that future versions of ReactJS will contain more primitives which might make it easier to access your information without the aid of a rigid framework. Suspense works well when it’s connected to the main structure of your code. particularly the data layer, router, as well as server’s rendering environments Consequently, we should expect that third-party frameworks will remain to play a significant role in the React workspace throughout time. As you could have guessed, this would ultimately enhance the usefulness and adaptability of React.

Suspense is more than just data retrieval. On earlier React versions, suspense might also be employed for code splitting with React.lazy. That’s right—you guessed it—this aids with the easy adoption of React 18. To handle all asynchronous processes, including downloading data, and code, including graphics, Suspense must be expanded.

Server Components

As I mentioned earlier, server components are yet to be released. So why are we discussing it here if React 18 does not include it? Considering that it will be provided to be widely accessible as a React 18 future modification, possibly 18.1 itself, very soon. Since server components are predicted to revolutionize server engine rendering, we find it difficult to remain composed.

The actions of Server Components would allow programmers to create programs that work across both the client and the server.

How does it manage to do that? Server Components could integrate the enhanced efficiency of traditional server rendering with the rich client-side app interactivity. We may also anticipate good interoperability between concurrent features including streaming server rendering and server components.

Automatic Batching

By itself, batching is a very significant feature of React. React makes use of batching to enhance the performance of the code. You must understand what batching is. The method of bundling numerous state updates together into a single re-render is known as batching in React event handlers. As the name implies, the additional automatic batching feature in React 18 does automatic batching. Through setTimeout, promises, as well as native event handlers, it is now possible to batch event modifications automatically.

// Before: only React events were batched.

setTimeout(() => {

  setCount(c => c + 1);

  setFlag(f => !f);

  // React will render twice, once for each state update (no batching)

}, 1000);

// After: updates inside of timeouts, promises,

// native event handlers or any other event are batched.

setTimeout(() => {

  setCount(c => c + 1);

  setFlag(f => !f);

  // React will only re-render once at the end (that’s batching!)

}, 1000);

Transitions

When it comes to enhancing the rendering of UIs, this functionality is enormous. Let’s jump right into analyzing the impact of the Transition feature and how it may simplify our work.

We all know there are two types of updates: urgent and non-urgent. Urgent upgrades are required due to direct user-UI interaction. In the meantime, non-urgent updates consist of chores like altering UI views.

The way React handles non-urgent updates is changed by transitions. The recently introduced Transitions feature with React 18 handles non-urgent updates at transitions. These are delivered in bits and pieces. In the end, it aids in handling urgent and non-urgent changes more fluidly to increase the responsiveness of our UIs. However, we must distinguish between urgent and non-urgent upgrades in our codes. Hooks in React 18 allow for this.

We can employ the startTransition API to differentiate between urgent and non-urgent updates. React would treat startTransition updates as non-urgent. It will suspend these updates when a crucial update comes in. In reaction to such interruptions, React would throw away prior renders and just show the most recent update.

It is very evident at this time that Transitions was developed with ease of feature uptake in mind, similar to other features. There are two transitional hooks available as a result:

  • useTransition: for recently started transitions, such as values that track pending states.
  • startTransition: We are expected to use startTransition to start transitions whenever the useTransition hook is inaccessible.

import {startTransition} from ‘react’;

// Urgent: Show what was typed

setInputValue(input);

// Mark any state updates inside as transitions

startTransition(() => {

  // Transition: Show the results

  setSearchQuery(input);

});

The fact that React 18’s new features depend on each other at various stages is perhaps crucial to mention at this point. Concurrent rendering, for instance, enables transitions since it permits updates to be stopped, as in the instance of Transitions. In the instance that an update was re-suspended, the user would receive the most recent content. The transition update would be carried out by Transition in the background.

When we talk about the other brand-new hooks added to React 18, we’ll see more of these interdependencies.

New Features with Suspense

Due to the concurrent rendering capability, the React server currently enables suspense and it has more features. If a component tree section is not yet prepared for rendering, suspense allows you to declaratively describe the loading state for that segment. Suspense transforms the “UI loading state” into a declarative idea right out of the React programming model’s box. We might plan to construct more advanced tools atop.

Please be aware that Suspense in React 18 needs to be used in conjunction with the transition API. React would not be using fallback content in place of rendered data if you interrupted it during a transition. Instead, rendering will be postponed unless enough data is loaded. A problematic loading state will be prevented by doing this.

Redesigned Client and Server Rendering APIs

The React Team has highlighted strengthening the client-server rendering APIs as a primary focus in numerous media outlets thus far. This will lead to enhanced rendering engines and better responsiveness of apps built on React. They have done a good job of keeping this promise with React 18. Several client-server rendering APIs that are exported and then recreated specifically to work with React 18 are supported by React 18. These aid in facilitating a more seamless switch from older versions of React to version 18. As a result, the new update’s adaptability element has also been given top priority.

Client DOM

The createRoot and hydrateRoot APIs are exported by React 18 from react-dom/client. The new features of React 18 might not work if they are not applied. OnRecoverableError is supported by each of these two APIs. This new function notifies developers when React corrects any potential rendering or hydration-related problems. In prior browsers, React would automatically utilize console.error and reportError.

  • createRoot: ReactDOM.render has taken the place of createRoot to unmount or use rendering to create a new root.
  • hydrateRoot: ReactDOM.hydrate has taken the place of hydrateRoot to hydrate server-rendered apps with the new DOM Server APIs.

Server DOM

Based on the react-dom/current server’s APIs, additional APIs for DOM servers have been made. They support suspense on the server side. Even if renderToString is still usable in React 18, it is better to avoid using it now that these are available to React.

  • renderToPipeableStream allows streams to be converted into pipeable streams in Node environments.
  • renderToReadableStream allows streams to be rendered to read-only streams in modern edge runtime environments including Cloudflare workers and Deno.

Strict Mode

The capability to add and remove UI elements while maintaining the state is currently being added by React. In React, the previous screen must be immediately visible. Consider the situation of a user who switches between displays. React can use component state while unmounting and remounting trees to do this. React apps will perform faster with this feature. However, components must be resistant to the mounting as well as deletion of effects repeatedly. Most effects will function as intended. Others could speculate that they had previously been mounted or destroyed.

React 18 improves Strict Mode by adding a new development-only test to aid in identifying these problems. After all, components mount for the first time, this new check will immediately unmount or remount them, restoring the previous state on the succeeding mount.

So when a component is already in development mode, the Strict Mode replicates unmounting as well as remounting of the component.

* React mounts the component.

  * Layout effects are created.

  * Effects are created.

* React simulates unmounting the component.

  * Layout effects are destroyed.

  * Effects are destroyed.

* React simulates mounting the component with the previous state.

  * Layout effects are created.

  * Effects are created.

Newly Added Hooks in React 18

React hooks are crucial for devs and the effective development process. A little review of React hooks is in order. Hooks are pre-made elements that we may use throughout our programs and get from the React framework. In addition to being easily accessible, they remove the need to repeatedly rewrite components when developing an application. By virtue of their “use-” prefix, hooks may be easily distinguished.

Consequently, React 18, as with any significant version upgrade, has to develop a few new hooks to guarantee that all additional features operate without a hitch. The additional hooks also contribute to React 18’s increased versatility. Let’s go through React 18’s most significant new hooks one at a time.

useID

Separate IDs are produced on the server and the client uses useId to prevent hydration inconsistencies. It is especially helpful when combining component libraries with accessibility APIs that demand unique IDs. The added streaming server renderer in React 18 corrects a flaw in earlier iterations of the framework, such as React 17 and 16. It broadcasts HTML out-of-order. It might be important to note at this point that useId is not known to offer keys as a list. The keys must appear from your data.

useTransition

As was already indicated, you can determine which state updates do not qualify as urgent by using the useTransition as well as startTransition hooks. Whenever a state update is classified as non-urgent, subsequent state updates are instantly marked as urgent. Less urgent state changes are paused by React to create a place for more critical ones. As was once again stated, these hooks depend on concurrent rendering.

useDeferredValue

You can postpone re-rendering any non-urgent tree component using the useDeferredValue hook. Although debouncing and this method are similar, they differ significantly in some important ways. There is no minimum time frame for the delay, thus React will execute the postponed render as soon as the original render comes on screen. Interruptible and not blocking user input are deferred renderings.

useSyncExternalStore

A new hook called UseSyncExternalStore simultaneously updates external storage. This enables them to control concurrent rendering. Any library outside of React that interacts with a state should make use of it. The useEffect rule is dropped when generating subscriptions to external data sources.

useInsertionEffect

The CSS-in-JS libraries can handle rendering performance issues by employing the new hook useInsertionEffect. You would necessarily not need this until you’ve developed a CSS-in-JS library. This hook will execute following a DOM modification, however before the layout engine reads the modified layout. A problem with React version 17.0 is fixed by doing this. However, it becomes even more crucial in React version 18.0. React 18 gives in to the browser to give the layout time to update during concurrent rendering.

Things to look forward to in the future React Updates

Concurrent React is among the most exciting components for performance improvement. Earlier versions of React had an initial element of suspense. The promise of React 18’s capabilities has been fully realized. Concurrent guarantees performance while suspense opens the door for innovation. Suspense brings with it some significant promises for innovation in the React ecosystem’s future.

Concerns about adoption have been well-handled by React 18. React 18 has included some additional hooks to ensure that the new features function for the maintainers of third-party libraries. New clients, as well as server rendering APIs, have also been added. In essence, these are updated exports from previous APIs. This also enables the smooth and gradual adoption of React 18.

The most recent comments from the React Team contain much more enticing sneak peeks at impending React releases. The first ones to be made available are React Server Components. We are also learning about the advantages of asset loading, SSR optimization, and transition tracing. Also being developed is the React Optimizing Compiler, which was unveiled at React Conf 2021.

Conclusion:

We’re getting close to the end of this conversation. Ever since it was stated that React 18 will arrive in 2021, there have been numerous rumours about what would take place. We anticipated that the focus of the future React version will be on third-party library maintenance. As we now see, this was generally true. Meaningful transition is given a lot of focus in React 18, although it is packed with new features. Several new features were added including Concurrent React, Automatic Batching, Suspense, and transitions. Additionally, the Server-Client DOM rendering engine has also been revamped. Hope you enjoy React 18!