Syncing clients

Setting up the server

As a quick reminder, let's see again the basic server set up:

import { WebSocketServer } from 'ws'

const server = new WebSocketServer({ port: 5001 })

server.on('connection', socket => {
  // do what we want with the socket
})

Tracking sockets

In order to update all the clients, we need to keep track of their server side sockets they have created.

Forunately, the WebSocketServer object keeps track of that for us in a property called clients.

import { WebSocketServer } from 'ws'

const server = new WebSocketServer({ port: 5001 })

server.on('connection', () => {
  console.log(server.clients) // lists all created sockets
})

Forwarding messages

When a client sends a message to its socket, we need to parse the message, then loop through and forward its content to every connected client.

import { WebSocketServer } from 'ws'

const server = new WebSocketServer({ port: 5001 })

server.on('connection', socket => {
  // when we receive a message
  // forward the message to all clients
  socket.on('message', message => {
    for (let client of server.clients) {
      client.send(message)
    }
  })
})

And that's it! Now all connected users will receive any message sent by any other user.