How to put an Express.JS app on Heroku with a domain?

Question

Heroku

I wrote a simple application in express.js (when accessing / returns Hello world!), But I ran into a problem: what port should I specify in app.listen if a domain is bound to my heroku application?
I tried to specify 80 but it returned me an error Error: listen EACCES: permission denied 0.0.0.0:80
I also specified 0 but it didn't return anything
Please help me.

Answer 1

Hold