suspense.jsx

import React from "react";
import ReactDOM from "react-dom";
import fetchWithCache from "./cache";

function Post({ postId }) {
  const post = fetchWithCache(
    "https://jsonplaceholder.typicode.com/posts/" + postId
  );
  return (
    <div>
      <h1>{post.title}</h1>
      <p>{post.body}</p>
    </div>
  );
}

const rootElement = document.getElementById("root");
ReactDOM.render(
  <React.Suspense fallback={<div>Loading...</div>}>
    <Post postId={1} />
  </React.Suspense>,
  rootElement
);