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

function App() {
  const [renderIndex, setRenderIndex] = useState(1);
  const refFromUseRef = useRef();
  const refFromCreateRef = createRef();
  if (!refFromUseRef.current) {
    refFromUseRef.current = renderIndex;
  }
  if (!refFromCreateRef.current) {
    refFromCreateRef.current = renderIndex;
  }
  return (
    

      Current render index: {renderIndex}
      

      First render index remembered within refFromUseRef.current:
      {refFromUseRef.current}
      

      First render index unsuccessfully remembered within
      refFromCreateRef.current:
      {refFromCreateRef.current}
      

       setRenderIndex(prev => prev + 1)}>
        Cause re-render
      
    
  );
}

const rootElement = document.getElementById("root");
ReactDOM.render(, rootElement);