Server IO Emit

Video Lecture

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.

./src/server/server.ts

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

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()