Description for parent links in Navigation Block

I solve this problem by using?WordPress Filter hooks

I use the filter render_block, to hook in altering the existing HTML

So I created custom_render_block_core_navigation_submenu hook function.

Inside my hook I am using conditions to avoid storing my modified code in the database.

• Target the type of block (core/navigation-submenu)
• Only render in the front-end
• Don’t alter the HTML in wp-json

In the function I check is title or description is avaliable, if yes, I create new list item element with title and/or description and insert this list item inside child list right after the opening <ul>

function custom_render_block_core_navigation_submenu(string $block_content, array $block): string

{

if (

isset($block['blockName']) &&

'core/navigation-submenu' === $block['blockName'] &&

!is_admin() &&

!wp_is_json_request()

) {

$additional_html = '';

// Add description if available.

if (!empty($block['attrs']['title']) || !empty($block['attrs']['description'])) {

$additional_html .= '<li class="wp-block-navigation-item">';

// Add title if available.

if (!empty($block['attrs']['title'])) {

$additional_html .= '<span class="wp-block-navigation-item__label">';

$additional_html .= wp_kses_post($block['attrs']['title']);

$additional_html .= '</span>';

}

// Add description if available.

if (!empty($block['attrs']['description'])) {

$additional_html .= '<span class="wp-block-navigation-item__description">';

$additional_html .= wp_kses_post($block['attrs']['description']);

$additional_html .= '</span>';

}

$additional_html .= '</li>';

}

// Find the position to insert $additional_html

$position = strpos($block_content, '<ul class="wp-block-navigation__submenu-container wp-block-navigation-submenu">');

if ($position !== false) {

// Insert $additional_html right after the opening <ul> tag

$position += strlen('<ul class="wp-block-navigation__submenu-container wp-block-navigation-submenu">');

$block_content = substr_replace($block_content, $additional_html, $position, 0);

}

}

return $block_content;

}

add_filter('render_block', 'custom_render_block_core_navigation_submenu', null, 2);