Creates a simple local state in react with hooks

state.js

import { useState } from 'react'; // hook

const Root = () => { // functional component
  const [ state, setState ] = useState(0); // local state for Root component
  const click = () => {
    setState( state + 1 ); // re-render Main component
  }

  console.log("render Main:", state);
  return ( // jsx
    <div>
      <p>State: { state }</p>
      <button onClick={ click  }>change state</button>
    </div>
  );
}