Repl with Custom Domain - Prevent Default Domain from Being Indexed by Search Engines

Let’s say I’ve got an HTML/JS/CSS repl, that I’ve linked to some custom domain,

I want to be indexed by search engines, but not (bc the url just isn’t as pretty).

How can I do this? Is this something that can be done with a robots.txt file or some setting in Replit or Cloudflare?

Or is this not even an issue that I need to worry about?

You could implement a JavaScript check to see if the domain ends with “”, and if it does, redirect the page to your custom domain.