FacetWP - variable products test

gistfile1.php

<?php

// Example - check for "in_stock" with a "Size" attribute
function show_instock_product_variations( $params, $class ) {
    if ( 'tax/pa_size' == $params['facet_source'] && 'product' == get_post_type( $params['post_id'] ) ) {
        WC()->api->includes();
        WC()->api->register_resources( new WC_API_Server( '/' ) );
        $response = WC()->api->WC_API_Products->get_product( $params['post_id'] );
        $product = $response['product'];

        if ( 'variable' == $product['type'] ) { // variable product
            foreach ( $product['variations'] as $variation ) { // loop through each variation
                $attr = $variation['attributes'][0];
                if ( 'tax/pa_' . $attr['slug'] == $params['facet_source'] ) { // correct variation
                    if ( $attr['option'] == $params['facet_value'] ) { // correct value
                        if ( true === $variation['in_stock'] ) { // in stock
                            return $params;
                        }
                        break;
                    }
                }
            }
            return false;
        }
        elseif ( ! $product['in_stock'] ) { // simple product (out of stock)
            return false;
        }
    }
    return $params; // default indexer
}
add_filter( 'facetwp_index_row', 'show_instock_product_variations', 10, 2 );