code: protected function dumpString($val)
      {
          if (\is_numeric($val)) {
              $date = $this->checkTimestamp($val);
              if ($date) {
                  $this->wrapAttribs['class'][] = 'timestamp';
                  $this->wrapAttribs['title'] = $date;
              }
          } else {
              if ($this->sanitize) {
                  $val = $this->debug->utf8->dump($val, true, true);
                  $val = $this->visualWhiteSpace($val);
              } else {
                  $this->wrapAttribs['class'][] = 'no-pseudo';
                  $val = $this->debug->utf8->dump($val, true, false);
              }
          }
          return $val;
      }
docs: Dump string
  
  @param string $val string value
  
  @return string