app.js

const express = require("express")
const app = express()
const http = require("http")
const socketio = require("socket.io")
const path = require("path")

const server = http.createServer(app)
const io = socketio(server)

app.set("view engine", "ejs")
app.use(express.static(path.join(__dirname, "public")))

io.on("connection", (socket) => {
  socket.on("sendLocation", function (data) {
    io.emit("newLocation", {id: socket.id, ...data})
  });

  socket.on("disconnect", () => {
    io.emit("userDisconnected", socket.id)
  })
})

app.get("/", (req, res) => {
  res.render("index")
}
)

server.listen(3000, () => {
  console.log("http://localhost:3000")
})