React's useState - how does it work?

useState is a hook in React that allows you to add state to your functional components. It returns an array with two elements: the current state value, and a function that updates it.

Here’s an example to help illustrate its usage:

import React, { useState } from 'react';

function Example() {
    const [count, setCount] = useState(0);
    
    return (
        <div>
            <p>You clicked {count} times</p>
            <button onClick={() => setCount(count + 1)}>
            Click me
            </button>
        </div>
    );
}

In this example, we’re using useState to store the number of times a button has been clicked. The initial state value is 0. The setCount function is used to update the state when the button is clicked.

You can use useState with any type of value, not just numbers. For example, you can store an object:

const [user, setUser] = useState({ name: 'John', age: 30 });

// later in your component:
setUser({ name: 'Jane', age: 25 });

or an array:

const [todos, setTodos] = useState([{ text: 'Learn Hooks' }, { text: 'Build App' }]);

// later in your component:
setTodos([...todos, { text: 'Publish App' }]);

You can use multiple instances of useState in the same component to store different pieces of state.