Automatically monitors websockets for unexpected disconnects, then terminates and sockets that stopped responding. This allows the onClose event to handle reconnects.

monitorWebsocket.js

// automatically monitors websockets for unexpected disconnects, then terminates and sockets that stopped responding.
// This allows the onClose event to handle reconnects.
const monitorWebsocket = ws => {
  ws.on('error', () => {
    ws.isAlive = true;
  });
  ws.on('close', () => {
    ws.isAlive = true;
  });

  ws.on('open', () => {
    ws.isAlive = true;
  });

  ws.on('pong', () => {
    ws.isAlive = true;
    ws.lastAlive = new Date();
  });

  ws.socketMonitor = setInterval(() => {
    if (!ws.isAlive) return ws.terminate();

    ws.isAlive = false;

    // ping will throw an exception if the ws closed earlier (e.g no network), so we'll only ping if the socket's still open
    if (ws.readyState === ws.OPEN) ws.ping();
  }, 10000);
};

module.exports = monitorWebsocket;