在多个设备上连接到节点websocket停止更新。

Question

所以，我正在学习websockets......下面的代码来自于一个教程，我一直在玩......当我通过一个react应用连接到它时，每秒钟的日期都会如期更新，当我然后用另一个浏览器标签或我的手机连接到它时，最新的实例如期更新，然而旧的实例现在停止了。

我本以为setInterval会清除并重新启动，向所有设备发出信号，使它们一起更新。

谁能给我点建议？如果我注释掉清除间隔，它就会像预期的那样工作，但是我知道这是不可能的，因为它只会创建越来越多的间隔事件。

const express = require("express");
const http = require("http");
const socketIo = require("socket.io");

const port = process.env.PORT || 4001;
const index = require("./routes/index");

const app = express();
app.use(index);

const server = http.createServer(app);

const io = socketIo(server);

let interval;

io.on("connection", (socket) => {
  console.log("New client connected");

  if (interval) {
    clearInterval(interval);
  }

  interval = setInterval(() => getApiAndEmit(socket), 1000);
  socket.on("disconnect", () => {
    console.log("Client disconnected");
    clearInterval(interval);
  });
});

const getApiAndEmit = socket => {
  const response = new Date();
  // Emitting a new message. Will be consumed by the client
  socket.emit("Test1", response);
};

server.listen(port, () => console.log(`Listening on port ${port}`));

Answer 1

嗨@Lawrence Ferguson。

所以，我们现在要做的不是使用单一的internval实例，而是通过socket的uniq id来创建间隔。

顺便说一下，通过 socket 绕着物体转真不是什么好事:)

const express = require("express");
const http = require("http");
const socketIo = require("socket.io");

const port = process.env.PORT || 4001;
const index = require("./routes/index");

const app = express();
app.use(index);

const server = http.createServer(app);

const io = socketIo(server);

let intervals = {};

io.on("connection", (socket) => {
    console.log("New client connected");

    // this is probably never gonna called,
    // cause you will get another socket.id when you connect again
    // So :D
    if (intervals && intervals[socket.id]) {
        clearInterval(intervals[socket.id]);
    }

    // instead of using a outside function
    // intervals[socket.id] = setInterval(() => getApiAndEmit(socket), 1000);
    // I'm always trying to use an internal val
    intervals[socket.id] = setInterval(() => {
        socket.emit("Test1", new Date());
    }, 1000);
    // But obv how ever you want to use :)

    socket.on("disconnect", () => {
        console.log("Client disconnected");
        clearInterval(intervals[socket.id]);
    });
});

const getApiAndEmit = socket => {
    const response = new Date();
    // Emitting a new message. Will be consumed by the client
    socket.emit("Test1", response);
};

server.listen(port, () => console.log(`Listening on port ${port}`));