How to find out where the user came to the site?

Question

JavaScript

I'm working on a project written in Next JS, I need to make a "go back" button, but provided that a person got to the page through our site, if through a third-party it throws them to the main page, this is so as not to lose the user.

I tried to write this code.

const handleUrlFromGoToSite = () => {
      if(!document.referrer.includes('mysait-url')) {
        Router.push('/');
      }
      else Router.back()
  };

But for some reason document.referrer always returns an empty string, no matter where I come from.

Answer 1

Come here , it might help.
This is done in PHP, you are unlikely to do it in JS.