JSFiddle - React, Tailwind, and code Playground

HTML

<input id="picker" type="file">
<div id=log></div>

JavaScript

picker.onchange = () => {
  const file = picker.files[0];
  const fileStream = file.stream();
  const fileStreamReader = fileStream.getReader();
  log.innerHTML = "";
  fileStreamReader.read().then(result => {
  	log.innerHTML += "PASS:" + result.done + ", " + result.value;
  }, e => {
   	log.innerHTML += "FAIL: error " + e;
  });
}