started edition of chat in node

+ handled cors
+ added css fo chat scroll and newline

tests_hugo/chat_node/chat_server/package.json

@@ -0,0 +1,8 @@
+{
+  "dependencies": {
+    "cors": "^2.8.5",
+    "express": "^4.18.2",
+    "nodemon": "^2.0.20",
+    "socket.io": "^4.5.3"
+  }
+}

tests_hugo/chat_node/chat_server/server.js

@@ -0,0 +1,45 @@
+//let app = require('express')();
+//let server = require('http').createServer(app);
+//let io = require('socket.io')(http);
+
+const express = require('express');
+//const cors = require('cors');
+const app = express();
+const http = require('http');
+const server = http.createServer(app);
+const { Server } = require("socket.io");
+// https://socket.io/docs/v4/handling-cors/
+const io = new Server(server, {
+	cors: {
+		origin: "*"
+	}
+});
+
+// cors : https://stackoverflow.com/questions/7067966/why-doesnt-adding-cors-headers-to-an-options-route-allow-browsers-to-access-my
+// https://www.npmjs.com/package/cors
+//app.use(cors());
+
+//app.get("/", function (req, res) {
+//	console.log("req.headers: ");
+//	console.log(req.headers);
+//})
+
+io.on('connection', function (socket) {
+
+	console.log('a user is connected');
+
+	socket.on('disconnect', function () {
+		console.log('a user is disconnected');
+	})
+
+	socket.on('chat_message', function (msg) {
+		console.log('message received: ' + msg);
+		io.emit('chat_message', msg);
+	})
+
+});
+
+server.listen(3000, function () {
+	console.log('server running on 3000');
+})
+