react componentdidupdate hook code example
Example 1: componentdidupdate in hooks
const App = props => {
const didMountRef = useRef(false)
useEffect(() => {
if (didMountRef.current) {
doStuff()
} else didMountRef.current = true
}
}
Example 2: useeffect react
useEffect(() => {
window.addEventListener('mousemove', () => {});
return () => {
window.removeEventListener('mousemove', () => {})
}
}, [])
Example 3: react useEffect
import React, { useEffect } from 'react';
export const App: React.FC = () => {
useEffect(() => {
}, [])
return (
<div>Use Effect!</div>
);
}
Example 4: useeffect
import React, { useState, useEffect } from 'react';
function Example() {
const [count, setCount] = useState(0);
useEffect(() => { document.title = `You clicked ${count} times`; });
return (
<div>
<p>You clicked {count} times</p>
<button onClick={() => setCount(count + 1)}>
Click me
</button>
</div>
);
}
Example 5: useeffect componentdidmount
useEffect(() => {
messagesRef.on('child added', snapshot => {
const message = snapshot.val();
message.key = snapshot.key;
setMessages(messages.concat(message));
}, []);