react functional component on component did mount code example
Example 1: how to use componentdidmount in functional component
useEffect(() => {
if(!props.fetched) {
props.fetchRules();
}
console.log('mount it!');
}, []);
useEffect({
your code here
})
useEffect(() => {
}, [yourDependency]);
useEffect(() => {
return () => {
}
}, [yourDependency]);
Example 2: useeffect
function App() {
const [count, setCount] = useState(0);
useEffect(() => {
longResolve().then(() => {
alert(count);
});
}, []);
return (
<div>
<button
onClick={() => {
setCount(count + 1);
}}
>
Count: {count}
</button>
</div>
);
}