App.js

// App.js
...
...
...
const [isLoading, setIsLoading] = useState(false);
// Button 1  
const updateLoading = () => {
    setIsLoading(true);
    setIsLoading(false);
    // setting isLoading to "true" at last
    setIsLoading(true);
    // it will still print "false"
    console.log(isLoading);
  }

// Button 2
  const checkLoading = () => {
    // will print "true"
    console.log(isLoading);
  }
  return (
    <div>
      <button onClick={updateLoading}>Set loading</button>
      <button onClick={checkLoading}>Check loading</button>
    </div>
  );