code: public function getEmojiPattern()
      {
          if (null === self::$emojiPattern) {
              $codeString = '';
  
              foreach ($this->getEmojiCodeList() as $code) {
                  if (is_array($code)) {
  
                      $first = dechex(array_shift($code));
                      $last  = dechex(array_pop($code));
                      $codeString .= '\x{' . $first . '}-\x{' . $last . '}';
  
                  } else {
                      $codeString .= '\x{' . dechex($code) . '}';
                  }
              }
  
              self::$emojiPattern = "/[$codeString]/u";
          }
  
          return self::$emojiPattern;
      }
docs: Returns a regular expression pattern to detect emoji characters.
  
  @return string