subzey/index.js

## index.js
#!/usr/bin/env node

const { createServer } = require('http');

function serveStatic(req, res) {
	res.writeHead(200, {
		'Content-Type': 'text/html;charset=utf-8',
	});
	res.end(`
<!doctype html>
<html>
<body>
<script>
	window.addEventListener('beforeunload', () => {
		navigator.sendBeacon('/beacon/', JSON.stringify({"date": new Date().toISOString()}));
	});
</script>
<p><a href="https://example.com/">Navigate away</a>, refresh or close the page.</p>
</body>
</html>
		`);
};

function rcvBeacon(req, res) {
	const buffers = [
		Buffer.from('*** Got beacon! ***\n')
	];

	req.on('readable', () => {
		const chunk = req.read();
		if (chunk) {
			buffers.push(chunk);
		}
	});

	req.on('end', () => {
		buffers.push(Buffer.from('\n'));
		process.stdout.write(Buffer.concat(buffers));
	});

	res.writeHead(201);
	res.end();
}

function notFound(req, res) {
	res.writeHead(404);
	res.end();
}

const server = createServer((req, res) => {
	switch (req.url) {
		case '/':
			return serveStatic(req, res);
		case '/beacon/':
			return rcvBeacon(req, res);
		default:
			return notFound(req, res);
	}
});
server.on('listening', () => {
	process.stdout.write(`Listening on http://${server.address().address}:${server.address().port}/\n`);
});
server.listen(8080, 'localhost');

## package.json
{
  "name": "beacon-test",
  "version": "0.0.1-alpha.1",
  "bin": "./index.js"
}
	#!/usr/bin/env node

	const { createServer } = require('http');

	function serveStatic(req, res) {
	res.writeHead(200, {
	'Content-Type': 'text/html;charset=utf-8',
	});
	res.end(`
	<!doctype html>
	<html>
	<body>
	<script>
	window.addEventListener('beforeunload', () => {
	navigator.sendBeacon('/beacon/', JSON.stringify({"date": new Date().toISOString()}));
	});
	</script>
	<p><a href="https://example.com/">Navigate away</a>, refresh or close the page.</p>
	</body>
	</html>
	`);
	};

	function rcvBeacon(req, res) {
	const buffers = [
	Buffer.from('* Got beacon! *\n')
	];

	req.on('readable', () => {
	const chunk = req.read();
	if (chunk) {
	buffers.push(chunk);
	}
	});

	req.on('end', () => {
	buffers.push(Buffer.from('\n'));
	process.stdout.write(Buffer.concat(buffers));
	});

	res.writeHead(201);
	res.end();
	}

	function notFound(req, res) {
	res.writeHead(404);
	res.end();
	}

	const server = createServer((req, res) => {
	switch (req.url) {
	case '/':
	return serveStatic(req, res);
	case '/beacon/':
	return rcvBeacon(req, res);
	default:
	return notFound(req, res);
	}
	});
	server.on('listening', () => {
	process.stdout.write(`Listening on http://${server.address().address}:${server.address().port}/\n`);
	});
	server.listen(8080, 'localhost');
	{
	"name": "beacon-test",
	"version": "0.0.1-alpha.1",
	"bin": "./index.js"
	}