GrumPHP\Collection\ProcessArgumentsCollection::addOptionalArgument PHP Method

    public function addOptionalArgument($argument, $value)
    {
        if (!$value) {
            return;
        }
        $this->add(sprintf($argument, $value));
    }

 /**
  * @param ProcessArgumentsCollection $arguments
  * @param array $config
  * @return ProcessArgumentsCollection
  */
 protected function addArgumentsFromConfig(ProcessArgumentsCollection $arguments, array $config)
 {
     $arguments->addOptionalArgument('--standard=%s', $config['standard']);
     $arguments->addOptionalArgument('--warning-severity=0', !$config['show_warnings']);
     $arguments->addOptionalArgument('--tab-width=%s', $config['tab_width']);
     $arguments->addOptionalArgument('--encoding=%s', $config['encoding']);
     $arguments->addOptionalCommaSeparatedArgument('--sniffs=%s', $config['sniffs']);
     $arguments->addOptionalCommaSeparatedArgument('--ignore=%s', $config['ignore_patterns']);
     return $arguments;
 }