How to hide the "Add new comment" link on the add new comment page

Question

In Drupal 8+, the "Add comment" form can be shown on a separate page by going to Manage fields for the content type that has comments and unchecking the box Show reply form on the same page as comments.

This shows an Add new comment link on the node (in this case, an article):

The UX problem is that when you click the Add new comment link, you are taken to a new path (for example, comment/reply/node/2/comment#comment-form) but the Add new comment link is still there:

This is confusing because clicking the link merely returns you to the page you are already on, so it may appear that nothing has happened.

How can I remove this "Add new comment" link only on entities that have the comment form embedded (/comment/reply/entity/entity_id)?

Answer 1

/**
 * Implements hook_preprocess_HOOK().
 */
function mymodule_preprocess_links__node(&$variables) {
  if (\Drupal::routeMatch()->getParameter('field_name') === 'comment') {
    unset($variables['links']['comment-add']);
  }
}

Answer 2

Something like this should work (assuming you dont want it on the teaser too if its there):

function hook_preprocess_node(&$variables) {
  // Remove the "Add new comment" link on teasers or when the comment form is
  // displayed on the page.
  if ($variables['teaser'] || !empty($variables['content']['comments']['comment_form'])) {
    unset($variables['content']['links']['comment']['#links']['comment-add']);
  }
}