node.js Socket.io cors from null - node.js

Question

I created a server over ssl with Node.js and I will use socket.io.
When I type https://socket.com/test on the browser via my code below, it works. There is no problem.
var express = require('express');
var https = require('https');
var http = require('http');
var fs = require('fs');
var io = require('socket.io')(https);
// This line is from the Node.js HTTPS documentation.
var options = {
key: fs.readFileSync('/etc/ssl/ssl-keys/crunchsystem/key.pem'),
cert: fs.readFileSync('/etc/ssl/ssl-keys/crunchsystem/cert.pem')
};
var app = express();
// Create a service (the app object is just a callback).
var bodyParser = require('body-parser');
app.use(bodyParser.json());
app.get('/test',function(request, response) {
response.send(JSON.stringify({ status:'ok' }));
});
app.post('/order', function(request, response) {
if (request.body.restaurant_code !== undefined) {
io.of('/'+request.body.restaurant_code).emit('GetOrder', request.body.data);
}
response.send(JSON.stringify({ status: request.body.restaurant_code }));
});
// Create an HTTP service.
http.createServer(app).listen(80);
// Create an HTTPS service identical to the HTTP service.
https.createServer(options, app).listen(443);
However ... When I try to listen to the channel, it keeps giving a cors error.
<script type="text/javascript"
src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.0.4/socket.io.js"></script>
<script>
var socket = io.connect('https://socket.crunchsystems.com/foo');
console.log(socket);
socket.on('GetOrder', msg => {
console.log(msg)
})
</script>
from origin 'null' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
There's always this error.How do I solve this error? Can you help me?
I've tried all kinds of solutions, I've tried everything that happens on the Internet.