Remove POST_TYPE from custom post type permalink

Question

I have a post type named services with the following permalink DOMAIN/services/investing/ (Single Page Permalink).

I want the permalink to be changed like DOMAIN/investing/. I don't want the POST_TYPE in my permalink.

I updated the permalink settings in WP Dashboad. But it only changed to blog posts, not to the custom post types.

How can I customize the permalink of custom post types?

The POST_TYPE is created using register_post_type as below.

function cp_services() {
  register_post_type('Services', array(
    'labels' => array(
        'name' => 'Services',
        'singular_name' => 'service',
        'add_new_item' => 'Add New Service',
        'edit_item' => 'Edit Service',
    ),
    'description' => 'Services',
    'public' => true,
    'has_archive' => true,
    'menu_position' => 20,
    'show_in_menu' => true,
    'show_in_nav_menus' => true,
    'supports' => array('title','editor','thumbnail')
  ));
}

add_action('init', 'cp_services');

Answer 1

As @WebElaine commented on this question I tried the following code which worked for me.

First, remove the slug from the permalink

function na_remove_slug( $post_link, $post, $leavename ) {

  if ( 'services' != $post->post_type || 'publish' != $post->post_status ) {
      return $post_link;
  }

  $post_link = str_replace( '/' . $post->post_type . '/', '/', $post_link );

  return $post_link;
}

add_filter( 'post_type_link', 'na_remove_slug', 10, 3 );

Just removing the slug isn't enough. Right now, you'll get a 404 page because WordPress only expects posts and pages to behave this way. You'll also need to add the following:

function na_parse_request( $query ) {

  if ( ! $query->is_main_query() || 2 != count( $query->query ) || ! isset( $query->query['page'] ) ) {
      return;
  }

  if ( ! empty( $query->query['name'] ) ) {
      $query->set( 'post_type', array( 'post', 'services', 'page' ) );
  }
}

add_action( 'pre_get_posts', 'na_parse_request' );

Then refresh the permalink.