index.js

const express = require('express')
const cors = require('cors')
const mongoose = require('mongoose')
const authRoutes = require('./server/routes/auth')
const messageRoutes = require('./server/routes/messages')
const app = express()
const socket = require('socket.io')
const path = require('path')
require('dotenv').config()

app.use(
  cors({
    origin: '*',
    methods: '*',
  })
)
app.use(express.json())

mongoose
  .connect(process.env.MONGO_URL, {
    useNewUrlParser: true,
    useUnifiedTopology: true,
  })
  .then(() => {
    console.log('DB Connetion Successfull')
  })
  .catch((err) => {
    console.log(err.message)
  })

app.use('/api/auth', authRoutes)
app.use('/api/messages', messageRoutes)

// server frontend
if (process.env.NODE_ENV === 'production') {
  app.use(express.static(path.join(__dirname, '../client/build')))

  app.get('*', (req, res) =>
    res.sendFile(
      path.resolve(__dirname, '../', 'client', 'build', 'index.html')
    )
  )
} else {
  app.get('/', (req, res) => res.send('Please set to production'))
}

const server = app.listen(process.env.PORT, () =>
  console.log(`Server started on ${process.env.PORT}`)
)
const io = socket(server, {
  cors: {
    origin: '*',
    methods: '*',
  },
})

global.onlineUsers = new Map()
io.on('connection', (socket) => {
  global.chatSocket = socket
  socket.on('add-user', (userId) => {
    onlineUsers.set(userId, socket.id)
  })

  socket.on('send-msg', (data) => {
    const sendUserSocket = onlineUsers.get(data.to)
    if (sendUserSocket) {
      socket.to(sendUserSocket).emit('msg-recieve', data.msg)
    }
  })
})