FacetWP - map taxonomies of parent product to variation

.php

add_filter( 'facetwp_indexer_row_data', function( $rows, $params ) {

	$extra_taxonomies = array(
		'producttype'	=> 'product-type', // Facet WP facet name => taxonomy name
	);

	// Check if facet name is extra taxonomy
    if ( array_key_exists($params['facet']['name'], $extra_taxonomies) ){

    	// Set taxonomy to check
    	$taxonomy_to_check = $extra_taxonomies[$params['facet']['name']];

    	// Check if post is product variation and has a parent
        $parent_id = wp_get_post_parent_id($params['defaults']['post_id']);
        if(get_post_type($params['defaults']['post_id']) == 'product_variation' && $parent_id){

        	// Create new data row
	        $data_row = $params['defaults'];

	        // Get data from taxonomy
	        $parent_post_terms = wp_get_post_terms( $parent_id, $taxonomy_to_check);
	        foreach($parent_post_terms AS $taxonomy_term){
		        $data_row['facet_value'] = $taxonomy_term->slug;
		        $data_row['facet_display_value'] = $taxonomy_term->name;
		        $data_row['term_id'] = $taxonomy_term->term_id;
		        $data_row['parent_id'] = $taxonomy_term->parent;

		        // Append to rows
		        $rows[] = $data_row;
	        }

	    }

    }
    return $rows;
}, 10, 2 );