client.js

// 建立一個 WebSocket 物件，並連上 socket server
const ws = new WebSocket('ws://localhost:5566')

// 連線建立後
ws.onopen = () => {
  console.log('open connection to server')
}

// 連線斷開後
ws.onclose = () => {
  console.log('close connection to server')
}

// 收到 server 事件時，將事件中的訊息印出來
ws.onmessage = event => {
  console.log(event.data)
}