Drupal - Loading a library only for the front page

function mytheme_preprocess_page(&$variables) {
  if (\Drupal::routeMatch()->getRouteName() == 'view.frontpage.page_1') {
        $variables['#attached']['library'][] = 'mytheme/cuddly-slider';
    }
}

The other workaround would be using the method from drupal's path matcher interface which returns true if the current page is the front page.

function themename_preprocess_page(&$variables) {

//using the method from the pathmatcherinterface
  if (\Drupal::service('path.matcher')->isFrontPage()) {
    $variables['#attached']['library'][] = 'themename/cuddly-slider';
  }
}