Reply To: 2 select parent the child taxonomy acf

• nouredin.alhabal

• March 12, 2022 at 9:29 am

Here’s an example of how we solved this problem:

1. Pass Selected Parent Terms In AJAX
You need a JS hook to filter the AJAX request of the child field, and add a new argument that contains the chosen parent term(s):

<?php
add_action('acf/input/admin_footer', 'support_acf_152814_filter_child_ajax');
function support_acf_152814_filter_child_ajax()
{
    global $post;
    //areas where this functionality is needed
    if (!$post || !isset($post->ID) || get_post_type($post->ID) != 'my_posy_type')
        return;

?>
    <script type="text/javascript">
       (function($){

$(document).ready( function() {
    acf.add_filter('select2_ajax_data', function( data, args, $input, field, instance ){
        let parent_field_key = '<parent_field_key>'; // Parent Field
        let target_field_key = '<child_field_key>'; // Child Field

        if( data.field_key == target_field_key ){
            let parent = acf.getField(parent_field_key);
            if (parent) {
                data['parent_terms'] = parent.val(); //This is an array if the parent field is multiselect
            }
        }

          return data;

    });

});

})(jQuery);
    </script>
<?php

}

2. Filter Taxonomy Query of the Child Terms
Here, you need to catch the argument we introduced above, and modify the query accordingly.
What I do here, is that I get the ids of all children of the selected parents, and I use put them in the ‘include’ option of the terms query:

add_filter('acf/fields/taxonomy/query/key=child_field_key', 'support_acf_152814_child_terms_filter', 10, 3);
function support_acf_152814_child_terms_filter( $args, $field, $post_id ) {
    // Check if this is an ajax call
    $children_ids = [];
	if (wp_doing_ajax()) {
		if (isset($_POST['parent_terms'])) {
			$parent_terms = $_POST['parent_terms'];
            if (is_array($parent_terms) && !empty($parent_terms)) {
                foreach ($parent_terms as $parent_id) {
                    $new_children = get_term_children($parent_id, 'disease_categories');
                    if (!is_wp_error( $new_children )) {
                        $children_ids = array_merge($children_ids, $new_children);
                    }
                }
            }
            $args['include'] = $children_ids;
		}
	
	}

    return $args;
}

I tested the code above and it works in my case. Please @hube2 let me know if this can be improved further.