Example:
import React, { useState, useEffect } from 'react';
export default function App() {
const [count, setCount] = useState(0);
// Similar to componentDidMount and componentDidUpdate:
useEffect(() => {
// Update the document title using the browser API
document.title = `You clicked ${count} times`;
});
return (
<div>
<p>You clicked {count} times</p>
<button onClick={() => setCount(count + 1)}>
Click me
</button>
</div>
);
}
It equivalent to this in Class Component
import React from 'react';
export default class App extends React.Component {
constructor(props) {
super(props);
this.state = {
count: 0
};
}
componentDidMount() {
document.title = `You clicked ${this.state.count} times`;
}
componentDidUpdate() {
document.title = `You clicked ${this.state.count} times`;
}
render() {
return (
<div>
<p>You clicked {this.state.count} times</p>
<button onClick={() => this.setState({ count: this.state.count + 1 })}>
Click me
</button>
</div>
);
}
}