Simple FileSaver.js (https://www.npmjs.com/package/file-saver) example

file-saver.jsx

import { saveAs } from "file-saver";
	  
function DownloadContent() {
  const download = () => {
    const blob = new Blob(["Hello, world!"], {type: "text/plain;charset=utf-8"});
    saveAs(blob, "hello, world.txt");
  }
  return (
    <button onClick={download}>Download</button>
  )
}