Load specific library for RTL language in Drupal 8

Question

How to load specific library for RTL language in Drupal 8?

Solution

/**
 * @param $variables
 * Load specific library for pages with html attribute of RTL
 */
function mymodule_preprocess_html(&$variables)
{
    if ($variables['html_attributes']['dir'] == 'rtl') {
        /**
         * for arabic language for example
         */
        $variables['#attached']['library'][] = 'mymodule/rtl-css';
        $variables['#attached']['library'][] = 'mymodule/rtl-js';
    } else {
        /**
         * for english or french language
         */
        $variables['#attached']['library'][] = 'mymodule/ltr-css';
        $variables['#attached']['library'][] = 'mymodule/ltr-js';
    }
}