How to make node js express app what show data by subdomain what reversed by nginx

subdomain nginx.md

• add domain DNS record * A server-ip
• on server $ nano /etc/nginx/conf.d/app.conf

	server {
		add_header Access-Control-Allow-Origin *;
		listen 443 ssl;
		server_name *.domain.example;
		error_page 502 /502.html;
		
		location / {
			proxy_pass http://localhost:8198;
        		proxy_set_header Host $host;
		}

		location /502.html {
			root /var/www/html;
		}

		ssl_certificate_key /etc/letsencrypt/live/domain.example/privkey.pem;
		ssl_certificate /etc/letsencrypt/live/domain.example/fullchain.pem;
	}	

• make example express app $ nano ~/app.js $ npm i express

const express = require('express');
const app = express();

app.all('*', (req, res) => {
    console.log(req.subdomains);
    res.send("ok");
})

app.listen(8198);

$ node ~/app.js