Let me know if you accept pull requests? Dont want to waste time... :)

Perhaps we should throw an Exception if calling the validate method using an unsupported country code prefix?

Currently the library assumes that the validation method is only called after the isCountryCodeInEU( $countryCode ) method on an instance of the Countries class is called. I agree that we should probably design this in a better way... Open to any ideas you might have!

Perhaps we should throw an Exception if calling the validate method using an unsupported country code prefix?

This would require a new major version since it's a BC break.

Also, every support of new countries could be considered as a BC break like
#57

Maybe we should let the behavior be decided by the user, with

public function validateVatNumberFormat(string $vatNumber, bool $failIfUnknown = true): bool
{
    // ...
    if (! isset($this->patterns[$country])) {
        return !$failIfUnknown;
    }
    // ...
}

Still, exposing a method to know if the Vat country is supported could be useful

Currently the library assumes that the validation method is only called after the isCountryCodeInEU( $countryCode ) method on an instance of the Countries class is called.

If so, there is currently no call in the VatBundle
https://github.com/ibericode/vat-bundle/blob/32ab2529929952b5921e71763390f7453ca03423/src/Validator/Constraints/VatNumberValidator.php#L15-L51

And the methods/constraints are called validVatNumber and not validEUVatNumber which is an issue.

Somewhat within the same scope i would love to be able to get the patterns themselves per country in some way.
Usecase being the ability to add quick pre-validation using the html "pattern" attribute before making the call to validate the vat id