Server IO Emit

Video Lecture

Server IO Emit Server IO Emit Server IO Emit

Description

Emit a message to all connected sockets. Used most often when a server level event occurs, eg, a timer event occured and you want to send a message to all clients.

img/server-io-broadcast-emit.jpg

src/server/server.ts

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import express from "express"
import path from "path"
import http from "http"
import socketIO from "socket.io"

const port: number = 3000

class App {

    private server: http.Server
    private port: number

    private io: socketIO.Server

    constructor(port: number) {
        this.port = port

        const app = express()
        app.use(express.static(path.join(__dirname, '../client')))

        this.server = new http.Server(app)
        this.io = new socketIO.Server(this.server);

        this.io.on('connection', (socket: socketIO.Socket) => {
            console.log('a user connected : ' + socket.id)

            socket.emit("message", "Hello " + socket.id);

            socket.broadcast.emit("message", "Everybody, say hello to " + socket.id);

            socket.on('disconnect', function () {
                console.log('socket disconnected : ' + socket.id);
            });   
        })

        setInterval(() => { this.io.emit("random", Math.floor(Math.random() * 10)) }, 1000)
    }

    public Start() {
        this.server.listen(this.port)
        console.log( `Server listening on port ${this.port}.` )
    }

}

new App(port). Start()

src/client/client.ts

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class Client {
    private socket: SocketIOClient.Socket

    constructor() {
        this.socket = io();    

        this.socket.on("message", function (message: any) {
            console.log(message)
            document.body.innerHTML += message + "<br/>"
        })

        this.socket.on("random", function (message: any) {
            console.log(message)
            document.body.innerHTML += "Winning number is " + message + "<br/>"
        })
    }
}

const client = new Client()