Lifecycle with Class Components
App.js
class Lifecycle extends React.Component {
componentDidMount() {
// Initialize
}
componentDidUpdate() {
// Updated
}
componentWillUnmount() {
// Removed
}
}
Lifecycle with useEffect
App.js
function Lifecycle() {
const [count] = useState(0);
useEffect(() => {
console.log('count updated!')
return () => console.log('destroyed!')
}, [count]);
}
Challenge
Implement a CountdownTimer component that implements useState() and useEffect() in conjunction with setInterval to handle the timer. Make sure you use the useEffect() hook to call clearTimeout() when the component is destroyed.