What is the useEffect hook in React?

What is the useEffect hook in React?

The useEffect hook lets you perform side effects in function components. It runs after the render and can be used for data fetching, subscriptions, or manually changing the DOM.

Can you give me an example of how to use it?

Sure! Here's a simple example:

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

function Example() {
  const [count, setCount] = useState(0);

  useEffect(() => {
    document.title = `Count: ${count}`;
  }, [count]); // Runs when 'count' changes

  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={() => setCount(count + 1)}>Click me</button>
    </div>
  );
}

What does the second argument in useEffect do?

The second argument is an array of dependencies. useEffect will only re-run if any of the dependencies change. If you pass an empty array, it runs only once after the initial render.