setState4.js

import React, { useState, useEffect, useRef } from "react";
import ReactDOM from "react-dom";

function App() {
  const [count, setCount] = useState(0);
  const isFirstRun = useRef(true);

  useEffect(() => {
    if (isFirstRun.current) {
      //skip firstRun
      isFirstRun.current = false;
      return;
    }
    //here we are sure count has been change
    console.log("count", count);
  }, [count]);

  return (
    <div className="App">
      <h1>counter: {count}</h1>
      <button onClick={() => setCount(count => count + 1)}>
        click
      </button>
    </div>
  );
}

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);