WooCommerce product category list with child categories

pb-wc-product-category-list-with-child-categories

<?php
/**
 * WooCommerce product category list with child categories
 */
 
// Function to get top-level "product_cat" terms with their child terms (1 level only).
function pb_get_woocommerce_categories() {
  $taxonomy = 'product_cat';
  
  // If you wish to exclude "Uncategorized" term ID, use this function - https://gist.github.com/bencicpatricija/3eec5e8345202c7b06d4838219dff112
  $exclude  =  pb_get_product_uncategorized_term_id() 
  
  // Get top-level "Product category" terms.
  $categories = get_terms([
    'taxonomy' => $taxonomy,
    // 'exclude'  => $exclude,
    'parent'   => 0,
  ]);

  foreach ( $categories as $cat ) {
    // Create an array with top-level parent category's term as an array key.
    $cat_array[$cat->term_id] = [];

    // Get current top-level parent category's child terms.
    $child_categories = get_terms([
      'taxonomy'   => $taxonomy,
      'parent'     => $cat->term_id,
      'hide_empty' => false,
    ]);

    $sub_cat_array = [];

    foreach ( $child_categories as $child_cat ) {
      // Create an array with child category's term IDs.
      $sub_cat_array[] = $child_cat->term_id;
    }

    // Push array of child categories to previously created parent category's array.
    $cat_array[$cat->term_id] = $sub_cat_array;
  }

  return $cat_array;
}

// Example usage.
$categories = pb_get_woocommerce_categories();

foreach ( $categories as $parent_cat => $child_cats ) : ?>
  <h2><?php echo get_term( $parent_cat )->name; ?></h2>
  <ul>
    <?php foreach ( $child_cats as $sub_cat ) : ?>
      <li><?php echo get_term( $sub_cat )->name; ?></li>
    <?php endforeach; ?>
  </ul>
<?php endforeach; ?>