Based on the IP address of the visitor, it returns the country.
If you have a paid cloudflare account, you will be able to retrieve more specific geo information (eg the state in the US).
TODO: find someone that wants to code it or throw the 5$/month in my general direction so I can make it happen
index.js is the content of the Workers script.
If you aren't familiar with workers or wrangler, check the doc from cloudflare, it's quite clear.
- cp wrangler.example.toml wrangle.toml
- fill the missing information about your cloudflare account
- wrangler publish
Further documentation for Wrangler can be found here.