React UseTransition

React useTransition

Created By: chatGPT

React's useTransition is a hook that helps to manage loading states and control the rendering of your components smoothly, especially when dealing with updates that require more time to process. By using useTransition, you can make your application appear more responsive as it allows you to mark certain state updates as transitions, giving React a signal to prioritize urgent updates. Here's how you can use it:

import React, { useState, useTransition } from 'react';

const MyComponent = () => {
    const [isPending, startTransition] = useTransition();
    const [input, setInput] = useState('');
    const [list, setList] = useState([]);

    const handleChange = (event) => {
        const { value } = event.target;
        setInput(value);
        startTransition(() => {
            const newList = Array.from({ length: 2000 }, (_, i) => `${value} ${i}`);
            setList(newList);
        });
    };

    return (
        <div>
            <input 
                value={input} 
                onChange={handleChange} 
                placeholder="Type something..." 
            />
            {isPending ? <p>Loading...</p> : <ul>{list.map(item => <li key={item}>{item}</li>)}</ul>}
        </div>
    );
};

export default MyComponent;

In the example above, we create a simple input that updates a list of items based on its value. The key parts are:

useTransition returns an array: the first element is a boolean isPending indicating whether the transition is ongoing, and the second is the startTransition function used to wrap the update logic.
The handleChange function updates the input value instantly, thanks to setInput, while the large update to the list is wrapped in startTransition, allowing React to handle it as a lower-priority update.
The user sees a loading message while the list is being computed, providing feedback about the state of the application.

Performance improvement is achieved as useTransition allows updates to be divided into urgent and non-urgent tasks. Remember that transitions work best for state changes that don’t need an immediate UI response. This can be particularly useful in cases where you have a lot of data manipulation and you want to keep the UI responsive.