drupal 8 get node path code example

Example 1: Drupal 8 get page node current path

// Get current path.
$current_path = \Drupal::service('path.current')->getPath();
$path_alias = \Drupal::service('path.alias_manager')->getAliasByPath($current_path);

Example 2: drupal 8 get theme path

$themeHandler = \Drupal::service('theme_handler');
$themePath = $themeHandler->getTheme($themeHandler->getDefault())->getPath();