okumurakengo/index.html

## index.html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <h1>aa</h1>
    <button id="butOpenFile">butOpenFile</button>
    <button id="butDirectory">butDirectory</button>
<script>
// 参考：https://developers.google.com/web/updates/2019/08/native-file-system

let fileHandle;
butOpenFile.addEventListener('click', async (e) => {
  fileHandle = await window.chooseFileSystemEntries();
  const file = await fileHandle.getFile();
  const contents = await file.text();
  console.log(contents)
  // Do something with the file handle
});

function getNewFileHandle() {
  const opts = {
    type: 'saveFile',
    accepts: [{
      description: 'Text file',
      extensions: ['txt'],
      mimeTypes: ['text/plain'],
    }],
  };
  const handle = window.chooseFileSystemEntries(opts);
  return handle;
}

async function writeFile(fileHandle, contents) {
  // Create a writer (request permission if necessary).
  const writer = await fileHandle.createWriter();
  // Make sure we start with an empty file
  await writer.truncate(0);
  // Write the full length of the contents
  await writer.write(0, contents);
  // Close the file and write the contents to disk
  await writer.close();
}

// (async () =>
//     writeFile(await getNewFileHandle(), "aaa")
// )()

const butDir = document.getElementById('butDirectory');
butDir.addEventListener('click', async (e) => {
  const opts = {type: 'openDirectory'};
  const handle = await window.chooseFileSystemEntries(opts);
  const entries = await handle.getEntries();
  for await (const entry of entries) {
    const kind = entry.isFile ? 'File' : 'Directory';
    console.log(kind, entry.name);
  }
});
</script>
</body>
</html>
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<meta http-equiv="X-UA-Compatible" content="ie=edge">
	<title>Document</title>
	</head>
	<body>
	<h1>aa</h1>
	<button id="butOpenFile">butOpenFile</button>
	<button id="butDirectory">butDirectory</button>
	<script>
	// 参考：https://developers.google.com/web/updates/2019/08/native-file-system

	let fileHandle;
	butOpenFile.addEventListener('click', async (e) => {
	fileHandle = await window.chooseFileSystemEntries();
	const file = await fileHandle.getFile();
	const contents = await file.text();
	console.log(contents)
	// Do something with the file handle
	});

	function getNewFileHandle() {
	const opts = {
	type: 'saveFile',
	accepts: [{
	description: 'Text file',
	extensions: ['txt'],
	mimeTypes: ['text/plain'],
	}],
	};
	const handle = window.chooseFileSystemEntries(opts);
	return handle;
	}

	async function writeFile(fileHandle, contents) {
	// Create a writer (request permission if necessary).
	const writer = await fileHandle.createWriter();
	// Make sure we start with an empty file
	await writer.truncate(0);
	// Write the full length of the contents
	await writer.write(0, contents);
	// Close the file and write the contents to disk
	await writer.close();
	}

	// (async () =>
	// writeFile(await getNewFileHandle(), "aaa")
	// )()

	const butDir = document.getElementById('butDirectory');
	butDir.addEventListener('click', async (e) => {
	const opts = {type: 'openDirectory'};
	const handle = await window.chooseFileSystemEntries(opts);
	const entries = await handle.getEntries();
	for await (const entry of entries) {
	const kind = entry.isFile ? 'File' : 'Directory';
	console.log(kind, entry.name);
	}
	});
	</script>
	</body>
	</html>