MTShop/code/web/modules/custom/carousel/carousel.module

<?php

/**
 * @file
 * Contains carousel.module..
 */
use Drupal\Core\Field;
use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Implements hook_theme().
 */
function carousel_theme() {
  return [
    'carousel' => [
      'variables' => ['items' => NULL, 'settings' => NULL],
    ],
    'carousel_views' => [
      'variables' => [],
    ],
  ];
}

/**
 * Theme for carousel
 */
function template_preprocess_carousel(&$variables) {
  $items = $variables['items'];
  $settings = _carousel_format_settings($variables['settings']);
  $variables['attributes']['class'][] = 'owl-slider-field';
  $variables['attributes']['class'][] = 'owl-slider-wrapper';
  $variables['attributes']['class'][] = 'owl-carousel';
  $variables['attributes']['data-settings'] = json_encode($settings);

  $html = '';
  if (!empty($items)) {
    $i = 0;
    foreach ($items as $item) {
      $html .= '<div class="owl-item-inner owl-item-inner-' . $i . '">' . \Drupal::service('renderer')->render($item) . '</div>';
      $i++;
    }
  }
  $ouput = array(
    '#type' => 'markup',
    '#markup' => $html,
  );
  $variables['output'] = \Drupal::service('renderer')->render($ouput);
}

/**
 * Prepares variables for Views Carousel templates.
 *
 * Default template: carousel-views.html.twig.
 *
 * @param array $variables
 *   An associative array containing:
 *   - view: A View object.
 */
function template_preprocess_carousel_views(&$variables) {
  $handler = $variables['view']->style_plugin;
  $settings = _carousel_format_settings($handler->options);
  $variables['attributes']['data-settings'] = json_encode($settings);
  $variables['attributes']['class'][] = 'owl-slider-wrapper';
  $variables['attributes']['class'][] = 'owl-carousel';

  $variables['items'] = $settings['items'];
  $items = $variables['items'];
  if (!empty($items)) {
    $itm = 1;
	if ($items > $itm){
	$variables['attributes']['class'][] = 'owl-responsive';
	}
  }

  $attached = array(
    '#attached' => array('library' => array('carousel/owl-carousel'))
  );
  \Drupal::service('renderer')->render($attached);
  template_preprocess_views_view_unformatted($variables);
}

/**
 * Default settings for carousel
 */
function _carousel_default_settings($key = NULL) {
  $settings = array(
    'image_style' => '',
    'image_link' => '',
    'items' => 1,
    'margin' => 30,
    'autoplay' => FALSE,
	'autoplaySpeed' => 1000,
    'autoplayHoverPause' => FALSE,
	'autoplayTimeout' => 4000,
    'nav' => TRUE,
	'navSpeed' => 800,
	'loop' => TRUE,
	'navRewind' => FALSE,
	'rewindSpeed' => 1000,
    'dots' => FALSE,
    'dotsSpeed' => 800,
	'slideBy' => 1,
    'mouseDrag' => TRUE,
    'touchDrag' => TRUE,
	'pullDrag' => FALSE,
	'freeDrag' => FALSE,
	'stagePadding' => '',
	'merge' => FALSE,
	'mergeFit' => FALSE,
	'center' => FALSE,
	'autoWidth' => FALSE,
	'video' => FALSE,
	'videoHeight' => '',
	'videoWidth' => '',
  );

  return isset($settings[$key]) ? $settings[$key] : $settings;
}

/**
 * return formatted js array of settings
 */
function _carousel_format_settings($settings) {
  $settings['items'] = (int) $settings['items'];
  $settings['margin'] = (int) $settings['margin'];
  $settings['autoplay'] = (bool) $settings['autoplay'];
  $settings['autoplaySpeed'] = (int) $settings['autoplaySpeed'];
  $settings['autoplayHoverPause'] = (bool) $settings['autoplayHoverPause'];
  $settings['autoplayTimeout'] = (int) $settings['autoplayTimeout'];
  $settings['nav'] = (bool) $settings['nav'];
  $settings['navSpeed'] = (int) $settings['navSpeed'];
  $settings['loop'] = (bool) $settings['loop'];
  $settings['navRewind'] = (bool) $settings['navRewind'];
  $settings['rewindSpeed'] = (int) $settings['rewindSpeed'];
  $settings['dots'] = (bool) $settings['dots'];
  $settings['dotsSpeed'] = (int) $settings['dotsSpeed'];
  $settings['slideBy'] = (int) $settings['slideBy'];
  $settings['mouseDrag'] = (bool) $settings['mouseDrag'];
  $settings['touchDrag'] = (bool) $settings['touchDrag'];
  $settings['pullDrag'] = (bool) $settings['pullDrag'];
  $settings['freeDrag'] = (bool) $settings['freeDrag'];
  $settings['stagePadding'] = (int) $settings['stagePadding'];
  $settings['merge'] = (bool) $settings['merge'];
  $settings['mergeFit'] = (bool) $settings['mergeFit'];
  $settings['center'] = (bool) $settings['center'];
  $settings['autoWidth'] = (bool) $settings['autoWidth'];
  $settings['video'] = (bool) $settings['video'];
  $settings['videoHeight'] = (int) $settings['videoHeight'];
  $settings['videoWidth'] = (int) $settings['videoWidth'];

  if (isset($settings['image_style'])) {
    unset($settings['image_style']);
  }
  if (isset($settings['image_link'])) {
    unset($settings['image_link']);
  }

  return $settings;
}

/**
 * Convert a string of settings to array.
 * @param $str
 * @return string
 */
function _carousel_string_to_array($str) {
  $str = trim($str);
  $str = str_replace('[', '', $str);
  $str = str_replace(']', '', $str);
  $str = explode(',', $str);

  return $str;

}