Meet React 18 and the new updates on 2023

React, a popular JavaScript library for building user interfaces, continues to evolve in 2023 with various improvements and innovations. Let's explore some of the key updates that make React even more powerful and efficient.

1. Dual Mode Concurrency

React has introduced the concept of "Dual Mode Concurrency" to enhance the user experience in applications with large volumes of data. This functionality allows React to dynamically adjust the priority between rendering and user interactions, resulting in a faster and smoother response, even in high-load environments.

import React, { unstable_createRoot } from 'react';

const App = () => {
  const root = unstable_createRoot(document.getElementById('root'));

  root.render(<YourComponent />);
};

2. Automatic Code Generation

Automatic Code Generation in React simplifies development by allowing React to generate part of the necessary code based on common patterns. This approach significantly reduces boilerplate code, increasing developer productivity.

// Before
class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = { data: null };
  }

  componentDidMount() {
    // ... data fetching logic ...
    this.setState({ data: fetchedData });
  }

3. Advanced Hooks

New hooks have been added to provide more refined control over the component lifecycle and state logic. This includes hooks for handling asynchronous data more elegantly and efficiently, contributing to cleaner and more understandable code.

import { useState, useEffect, useAsync } from 'react';

const MyComponent = () => {
  const [data, setData] = useState(null);

  const fetchData = useAsync(async () => {
    const result = await fetch('https://api.example.com/data');
    const data = await result.json();
    setData(data);
  }, []);

  useEffect(() => {
    fetchData.execute();
  }, []);

  return <div>{data}</div>;
};

4. Enhancements in Server-Side Rendering

React has improved server-side rendering to provide a faster and more efficient experience, especially in applications heavily dependent on SEO. Enhancements include optimizations in the initial HTML generation and the ability to reuse initial state on the client.

// Server-side rendering with React 17
import { renderToString } from 'react-dom/server';

const App = () => {
  // ... main component ...
};

const html = renderToString(<App />);

5. Incremental Rendering

Incremental rendering in React allows only the changed parts of an interface to be updated, minimizing performance impact. This approach is particularly beneficial in large applications where frequent small updates are necessary.

import React, { useState } from 'react';

const IncrementalRenderingComponent = () => {
  const [count, setCount] = useState(0);

  const increment = () => {
    setCount(count + 1);
  };

  return (
    <div>
      <p>{count}</p>
      <button onClick={increment}>Increment</button>
    </div>
  );
};

These are simplified examples to illustrate the concepts. Remember to adapt the code as needed for your application context. Stay tuned for regular updates to make the most of these advancements and enhance your React applications.

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Comments

[Kevin]

Transitions in React offer a new way to prioritize UI changes. With transitions, you can distinguish between urgent and non-urgent updates to the UI. This differentiation allows you to prioritize the more critical updates over less urgent ones.

To take advantage of transitions, you need to use the new hook useTransition().

In the example code below, the useTransition() hook returns an array with two values: a boolean variable named isPending, which is set to true when a transition is taking place, and a function named startTransition, which initiates the transition by calling a callback function.

const [isPending, startTransition] = useTransition();

The code placed within the callback will be executed at a lower priority than state changes made outside of the startTransition function. This means that state changes not wrapped within the startTransition will have higher priority, while the state changes made within the callback will occur in the background.

The resulting concurrent render created with startTransitionis cancellable. If the user further makes changes that affect the validity of the render, that render will be interrupted and discarded. The overall effect of transitions is a more responsive UI.

It’s essential to understand the use case for state changes when using startTransition callback. This feature is primarily intended for transitioning from one render to another in React 18. The callback function must be a synchronous function; otherwise, it won’t work correctly.

If you want to read more about React 18, I highly recommend this blog post from Will Eizlini that describes in detail with some examples, some of these features:

scalablepath.com/react/react-18-re...