I implemented a synchronization function of drawing board with node.js, and the following warning appeared when npm install was executed. The picture is below. . .

  node.js, question


This is a warning message
I checked it online and said it was just a warning. It doesn’t matter, but there are still problems in the execution below. The screenshots are as follows

I would like to ask the following questions

var express = require('express'),
 app = express(),
 http = require('http'),
 socketIo = require('socket.io');
 var server = http.createServer(app);
 var io = socketIo.listen(server);
 App.use (express.static (_ _ dirname plus' /public');
 console.log("Server running on");
 // array of all lines drawn
 var line_history = [];
 // event-handler for new incoming connections
 io.on('connection', function (socket) {
 // first send the history to the new client
 for (var i in line_history) {
 socket.emit('draw_line', { line: line_history[i] } );
 // add handler for message type "draw_line".
 socket.on('draw_line', function (data) {
 // add received line to history
 // send line to all clients
 io.emit('draw_line', { line: data.line });

Try to change the port first, is 8080 occupied?