Date popup on exposed filter
Currently, exposed filters in Views in Drupal 8 don't use the new HTML5 elements.  Essentially, you get text inputs, selects, or checkboxes/radios.

There is an existing feature request to add this to Drupal 8.

I suspect you could form alter the exposed form to change the types.  This is untested, but essentially what the patch on that issue does:

function MYMODULE_form_views_exposed_form_alter(&amp;$form, \Drupal\Core\Form\FormStateInterface $form_state) {
  $form['the_exposed_date_element']['#type'] = 'date';
}


That won't work for ranges, but it should give you a start.