State Hooks

function Con() {
	
	const [val, setVal] = useState(0);

	return (
		<button onClick={() => setVal(val + 1)}>
		{val}
		</button>
	)
}

Passing state via props

// parent
export default function App() {

  const [val, setVal] = useState(0);

  return (
    <div className="App">
      <h1>{val}</h1>
      <Counter val={val} setVal={setVal}></Counter>
    </div>
  );
}

// child
export const Counter = ({val, setVal}) => {

  return (
    <button onClick={() => setVal(val + 1)}>
      press me
    </button>
  );
}