node.js+客户端掉线

const WebSocket = require('ws');
let ws = new WebSocket('ws://example.com');

ws.on('close', function close() {
  console.log('disconnected, trying to reconnect...');
  setTimeout(function() {
    ws = new WebSocket('ws://example.com');
  }, 2000);
});

const cluster = require('cluster');
const http = require('http');
const numCPUs = require('os').cpus().length;

if (cluster.isMaster) {
  console.log(`Master ${process.pid} is running`);

  // Fork workers.
  for (let i = 0; i < numCPUs; i++) {
    cluster.fork();
  }

  cluster.on('exit', (worker, code, signal) => {
    console.log(`worker ${worker.process.pid} died`);
  });
} else {
  // Workers can share any TCP connection
  // In this case it is an HTTP server
  http.createServer((req, res) => {
    res.writeHead(200);
    res.end('hello world\n');
  }).listen(8000);

  console.log(`Worker ${process.pid} started`);
}

window.addEventListener('beforeunload', function (e) {
  // 发送退出通知到服务器
  fetch('/api/logout', { method: 'POST' });
});