Show all tags NOT applied to post

Question

I'm working on a checklist within wordpress – I have a huge list of posts and I want to tag them with checks that have been done for the post.

However, I want to display all the tags not applied on this post.

For example:

---

Sarah's Document

Processes not checked yet: ISU-123, ISU-124, ISU-125

---

Andrew's Document

Processes not checked yet: ISU-125

---

I want to apply a reverse tagging method almost – I tag posts that have the processes applied to them and show a visual for process not yet tagged on each post.

Is there a way of using get_the_tags for showing tags not applied? Or perhaps doing a query for all tags and excluding an array?

Answer 1

if i have understood your question, you want all tags from a taxonomy not applied to your post?

maybe you can use get_terms('your_custom_taxonomy') to get all of your tags, and parse/diff to your current post tags to get all tags not applied to your post https://developer.wordpress.org/reference/functions/get_terms/

or maybe try to use a filter like list_term_exclusions with your current post https://developer.wordpress.org/reference/hooks/list_terms_exclusions/

Answer 2

After going through the tags / term functions, I've managed to write a function to solve this issue and wrap it in a function:

function tags_not_applied( ){
  // Get ID of post
  $post_id = get_the_ID();

  // Get post's current tags
  $tags_array = wp_get_post_terms( $post_id, 'taxonomy', array("fields" => "ids") );
  if (empty($tags_array))
    return;

  // Put all tags into array
  $args = array(
    'hide_empty' => false,
    'exclude' => $tags_array
  );

  // Get all tags except the ones applied
  $terms = get_terms( 'taxonomy', $args );

  if (empty($terms))
    return;

  // Create list of tags not applied
  $html = '<ul class="tags_not_applied">';
  foreach ( $terms as $term ) {
    $term_link = get_term_link( $term->term_id );

    $html .= "<li><a href='{$term_link}' title='{$term->name} term' class='patch patch-{$term->slug}'>";
    $html .= "{$term->name}</a></li>";
  }
  $html .= '</ul>';
  echo $html;
}

Thing to note is that get_terms by default has hide_empty as true, which causes the assumption that nothing is being returned!