I successfully made a chatroom that is based on node.JSs socket.io package. So I have basically one .html file in and a couple of .js files.
So basically what I have currently is the foundation for a website with a chat app.
My question is, is there something I need to think before uploading this to a domain? Will the chat app still be working when I upload it with something like say FileZilla?
You need a webserver that at least runs runs node.js. There are some PaaS solutions out here you can check out here: https://geekflare.com/nodejs-hosting-platform/
For a small application I can recommend Heroku. What you have to do is described here: https://devcenter.heroku.com/articles/getting-started-with-nodejs
If you already have some webspace and this question isn't meant as the beginner level might sound, you need can upload your stuff with any software to your server.