List subcategories of a specific product category (adapting from posts to products taxonomy)

Question

I made the below for my sidebar to show the subcategories of a specific category (ID 89) of my choosing. Only the subcategories that the post is in appear. Works great.

Now I want to change my posts in to WooCommerce Products, so I'm trying to adapt the code to target WC subcategories instead of post categories. I'm a bit lost on where to start.

<ul>
    <?php foreach (get_the_category() as $childcat) : ?>
    <?php if (cat_is_ancestor_of(89, $childcat)) { ?>
        <li>
            <a href="<?php echo get_category_link($childcat->term_id); ?>"><?php echo $childcat->cat_name; ?></a>
        </li>
    <?php } ?>
    <?php endforeach; ?>
</ul>

Answer 1

...to show the subcategories of a specific category (ID 89) ...

Try this

$product_cats = wp_get_post_terms( $post->ID, 'product_cat' );
if ( ! empty( $product_cats ) && ! is_wp_error( $product_cats ) ) { ?>
<ul>
    <?php 
    foreach ($product_cats as $childcat) : ?>
    <?php if ($childcat->parent == 89)) { ?>
        <li>
            <a href="<?php echo get_term_link($childcat->term_id); ?>"><?php echo $childcat->name; ?></a>
        </li>
    <?php } ?>
    <?php endforeach; ?>
</ul>
<?php } ?>

I hope this helps.