1_emoji_type.php

<?php

class EmojiType extends AbstractType
{
    public function getParent()
    {
        return CountryType::class;
    }

    public static function getEmojiFlag(string $countryCode): string
    {
        $regionalOffset = 0x1F1A5;

        return mb_chr($regionalOffset + mb_ord($countryCode[0], 'UTF-8'), 'UTF-8')
            . mb_chr($regionalOffset + mb_ord($countryCode[1], 'UTF-8'), 'UTF-8');
    }
  
    public function configureOptions(OptionsResolver $resolver)
    {
      // the magic is coming, continue to read
    }
}