Minimal Live Reload

server.js

const listeners = new Set();
const addSubscriber = (res) => {
  res.writeHead(200, {
    "Content-Type": "text/event-stream",
    Connection: "keep-alive",
    "Cache-Control": "no-cache",
  });

  listeners.add(res);
};
const triggerReload = (res) => {
  for (const lRes of listeners) lRes.write("data: reload\n\n");
  res.end();
};
const getReloadScript = (path) => `<script>
  new EventSource("${path}").onmessage = () => location.reload();
</script>`;

require("http")
  .createServer((req, res) => {
    if (req.url === "/~_" && req.method === "GET") {
      addSubscriber(res);
    } else if (req.url === "/~_" && req.method === "POST") {
      triggerReload(res);
    } else if (
      req.method === "GET" &&
      (req.url === "/index.html" || req.url === "/")
    ) {
      res.writeHead(200, { "Content-Type": "text/html" });
      res.write(`${require("fs").readFileSync('./index.html')} ${getReloadScript("/~_")}`);
      res.end();
    } else {
      res.writeHead(404);
      res.end();
    }
  })
  .listen(3000, () => {
    console.log("Server listening on port http://localhost:3000");
  });

terminal.sh

# in one terminal
node server.js
# in another terminal
watchexec -e html,css,js 'curl -X POST http://localhost:3000/~_'