4_emoji_type.md

class EmojiType extends AbstractType
{
  
    public function configureOptions(OptionsResolver $resolver)
    {

                        $countriesCode = Countries::getNames($options['choice_translation_locale']);
+                        // If the option "only_emoji" is true, we display just the emoji
+                        if (true === $options['only_emoji']) {
+                            foreach ($countriesCode as $countryCode => $displayed) {
+                                $choices[$countryCode] = self::getEmojiFlag($countryCode);
+                            }
+                        } else {
+                        // else we display the emoji and the country name
                            foreach ($countriesCode as $countryCode => $displayed) {
                                $choices[$countryCode] = self::getEmojiFlag($countryCode).' '.$displayed;
                            }
                        }

                        return array_flip($choices);
                });
                        },
                'choice_translation_locale' => null,
+                // define the option and set "false" by default
+                'only_emoji' => false
    ]);

        $resolver->setAllowedTypes('choice_translation_locale', ['null', 'string']);
+        // the option should be a boolean
+        $resolver->setAllowedTypes('only_emoji', ['boolean']);
    }
}