Empty regions render even when the block is set to "Hide block if the view output is empty"

[jvogtuw]

This is a known issue in core with the rendering process and there are no core solutions at this time.

Main issue: https://www.drupal.org/project/drupal/issues/953034

Honorable mentions:

• https://www.drupal.org/project/drupal/issues/2937582
• https://www.drupal.org/project/drupal/issues/2685157

One suggested workaround of checking for region content with page.second_sidebar|render|striptags('<img><iframe><object><svg>')|trim|length doesn't solve the issue for this theme. As mentioned in this comment, the "the real problem is that <drupal-render-placeholder> gets replaced with either something empty or not."

[jvogtuw]

Would it be a terrible idea to work around this with JavaScript? The following does the trick, but it sort of skirts around the rendering system.

Add the following to uw_boundless/js/script.js inside jQuery(document).ready(function($) {});:

// Hides empty sidebar regions.
// Workaround for empty sidebar regions rendering when a lazy loaded block
// turns out to be empty. This is an issue with the core rendering process.
// See https://www.drupal.org/project/drupal/issues/953034
// See https://www.drupal.org/project/drupal/issues/2685157
// See https://www.drupal.org/project/drupal/issues/2937582
let sidebar_first = $('.region-sidebar-first');
let sidebar_second = $('.region-sidebar-second');
if (isEmpty(sidebar_first) && isEmpty(sidebar_second)) {
  // Remove the empty elements.
  $(sidebar_first).remove();
  $(sidebar_second).remove();

  // Adjust the main content bootstrap width class.
  let main_content = $('.uw-sidebar-shown');
  $(main_content)
    .addClass('uw-sidebar-hidden')
    .addClass('col-sm-12')
    .removeClass('uw-sidebar-shown')
    .removeClass('col-md-8');
}

And the isEmpty() function:

/**
 * Checks if an HTML element is empty.
 */
function isEmpty(ele) {
  return $.trim($(ele).html()) === '';
}

I'll roll this in a week if no one objects.