react-useeffect-mount.js

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

const UseEffectClickCounterMount = (props) => {
  const [clicks, setClicks] = useState(initialClicks || 0);
  const incrementClicks = () => {
    setClicks(clicks + 1);
  };
  
  // Our 'componentDidMount' with hooks, give an empty dependency list!
  useEffect(() => {
    alert('The click counter has mounted!');
  }, []); // Do not forget to send an empty list! Undefined won't work!
  
  useEffect(() => {
    alert(`Clicks were updated to ${clicks}`);
  }, [ clicks ]);
  
  return <>
      <h1>Click Counter</h1>
      <p>Amount of clicks: {clicks}</p>
      <button onClick={incrementClicks}>Click me!</button>
    </>;
};