node.js: socket.io服务端和客户端交互示例

npm install express socket.io

"type": "module",

// server.js
import express from "express";
import { createServer } from "http";
import { Server } from "socket.io";
import path from "path";
const __dirname = path.resolve();
const app = express();
const server = createServer(app);
const io = new Server(server);
// http
app.get("/", (req, res) => {
  res.sendFile(__dirname + "/index.html");
});
// websocket
io.on("connection", (client) => {
  console.log("socket connection");
  // 消息发送
  client.on("chat message", (msg) => {
    io.emit("chat message", msg);
  });
  // 断开连接
  client.on("disconnect", () => {
    console.log("socket disconnect");
  });
});
server.listen(3000, () => {
  console.log("server start");
});

<!-- index.html -->
<!-- 消息输入 -->
<form id="form">
  <input id="input" type="text" />
  <button>发送</button>
</form>
<!-- 消息显示 -->
<div id="message-list"></div>
<script src="socket.io/socket.io.js"></script>
<script>
  const form = document.querySelector("#form");
  const input = document.querySelector("#input");
  const messageList = document.querySelector("#message-list");
  const socket = io();
  // 发送消息
  form.addEventListener("submit", function (event) {
    event.preventDefault();
    if (input.value) {
      socket.emit("chat message", input.value);
      input.value = "";
    }
  });
  // 接收消息
  socket.on("chat message", (msg) => {
    const li = document.createElement("li");
    li.textContent = msg;
    messageList.appendChild(li);
  });
</script>