Display WC categories/subcategories on shop and archive templates

functions.php

add_action( 'woocommerce_before_shop_loop', 'example_woo_list_categories' );

/**
 * Action Callback
 */
function example_woo_list_categories() {
	$result = false;
	$output = '';
	if ( is_product_category() ) {
		$queried_object = get_queried_object();
		$parent = $queried_object->term_id;
		$result = true;
	} else if ( is_shop() ) {
		$parent = 0;
		$result = true;
	} else {
		$result = false;
	}

	if ( $result ) {
		$args = array(
			'taxonomy'     => 'product_cat',
			'orderby'      => 'name',
			'show_count'   => 0,
			'pad_counts'   => 0,
			'hierarchical' => 1,
			'title_li'     => '',
			'hide_empty'   => 0,
			'parent'       => $parent
		);
		$categories = get_categories( $args );

		$output .= '<div class="subcats-list">';
		$output .= '<ul class="subcategories">';
		foreach ( $categories as $cat ) {
			$subcategory = get_term_by( 'id', $cat->term_id, 'product_cat' );

			if ( $subcategory && $subcategory->count != 0 ) {
				$output .= '<li class="subcategory">';
				$output .= '<a target="_self" href="' . esc_url( get_term_link( $cat, 'product_cat' ) ) . '">';
				$output .= $subcategory->name;
				$output .= '</a>';
				$output .= '</li>';
			}
		}
		$output .= '</ul>';
		$output .= '</div>';
	}

	echo $output;
}