Add variation stock quantity and status to Woocommerce product variation dropdown

Based on “Show stock status next to each attribute value in WooCommerce variable products“, I have the following code that shows stock quantity + stock status in product variation dropdown and also as displayed product availability text:

add_filter( 'woocommerce_variation_option_name', 'customizing_variations_terms_name', 10, 1 );
function customizing_variations_terms_name( $term_name ){

    if(is_admin())
        return $term_name;

    global $product;
    $second_loop_stoped = false;

    // Get available product variations
    $product_variations = $product->get_available_variations();

    // Iterating through each available product variation
    foreach($product_variations as $variation){

        $variation_id = $variation['variation_id'];
        $variation_obj = new WC_Product_Variation( $variation_id );

        ## WOOCOMMERCE RETRO COMPATIBILITY ##
        if ( version_compare( WC_VERSION, '3.0', '<' ) ) # BEFORE Version 3 (older)
        {
            $stock_status = $variation_obj->stock_status;
            $stock_qty = intval($variation_obj->stock);

            // The attributes WC slug key and slug value for this variation
            $attributes_arr = $variation_obj->get_variation_attributes();
        }
        else # For newest verions: 3.0+ (and Up)
        {
            $stock_status = $variation_obj->get_stock_status();
            $stock_qty = $variation_obj->get_stock_quantity();

            // The attributes taxonomy key and slug value for this variation
            $attributes_arr = $variation_obj->get_attributes();
        }

        if(count($attributes_arr) != 1) // Works only for 1 attribute set in the product
            return $term_name;

        // Get the terms for this attribute
        foreach( $attributes_arr as $attr_key => $term_slug){
            // Get the attribute taxonomy
            $term_key = str_replace('attribute_', '', $attr_key );

            // get the corresponding term object
            $term_obj = get_term_by( 'slug', $term_slug, $term_key );
            if( $term_obj->name == $term_name ){ // If the term name matches we stop the loops
                $second_loop_stoped = true;
                break;
            }
        }
        if($second_loop_stoped)
            break;
    }
    if( $stock_qty>0 )
        return $term_name .= ' - ' . $stock_status . ' ('.$stock_qty.')';
    else
        return $term_name .= ' - ' . $stock_status . ' (Vyprodáno)';
}

add_filter( 'woocommerce_get_availability', 'custom_get_availability', 1, 2);
function custom_get_availability( $availability, $_product ) {
    global $product;
    $stock = $product->get_total_stock();

    if ( $_product->is_in_stock() ) $availability['availability'] = __($stock . ' Skladem', 'woocommerce');
    if ( !$_product->is_in_stock() ) $availability['availability'] = __('Vyprodáno', 'woocommerce');

  return $availability;
}

But I am having an issue with this code:
for ex. I have a product with size (stock): S (instock qty 2), L(0), XL(0). When I select variation S – it shows Quantity 2 – that is correct, but this same quantity is shown even when I select variation L or XL. – that is wrong because they are on ZERO. Can anybody help me with this? Thank you!

You can see it here: https://dogworld.cz/produkt/pelisek-pro-psa-reedog-beige-paw/

Answer

There are some mistakes in your code and a better way to shows stock quantity + stock status in product variation dropdown.

The first function is a custom function where you will define the stock text addition to be displayed in the product variation dropdown, which is handled by the second function.

In your last function, since Woocommerce 3, get_total_stock() is deprecated and replaced by the method get_stock_quantity(). Also you need to use the variation $product object that is included as an argument in the hooked function.

Note: This will only work for variable products with one dropdown (one defined product attribute for variations)

Here is the revisited code:

// Function that will check the stock status and display the corresponding additional text
function get_variation_stock_text( $product, $name, $term_slug ){
    foreach ( $product->get_available_variations() as $variation ){
        if($variation['attributes'][$name] == $term_slug ){
            $is_in_stock = $variation['is_in_stock'];
            $stock_qty   = get_post_meta($variation['variation_id'], '_stock', true);
        }
    }
    $in_stock     = ' ('.$stock_qty.' ' .__("Skladem", "woocommerce").')';
    $out_of_stock = ' ('.__("Vyprodáno", "woocommerce").')';

    return $is_in_stock == 1 ? $in_stock : $out_of_stock;
}

// The hooked function that will add the stock text to the dropdown options elements.
add_filter( 'woocommerce_dropdown_variation_attribute_options_html', 'show_stock_status_in_dropdown', 10, 2);
function show_stock_status_in_dropdown( $html, $args ) {
    // Only if there is a unique variation attribute (one dropdown)
    if( sizeof($args['product']->get_variation_attributes()) == 1 ) :

    $options               = $args['options'];
    $product               = $args['product'];
    $attribute             = $args['attribute']; // The product attribute taxonomy
    $name                  = $args['name'] ? $args['name'] : 'attribute_' . sanitize_title( $attribute );
    $id                    = $args['id'] ? $args['id'] : sanitize_title( $attribute );
    $class                 = $args['class'];
    $show_option_none      = $args['show_option_none'] ? true : false;
    $show_option_none_text = $args['show_option_none'] ? $args['show_option_none'] : __( 'Choose an option', 'woocommerce' );

    if ( empty( $options ) && ! empty( $product ) && ! empty( $attribute ) ) {
        $attributes = $product->get_variation_attributes();
        $options    = $attributes[ $attribute ];
    }

    $html = '<select id="' . esc_attr( $id ) . '" class="' . esc_attr( $class ) . '" name="' . esc_attr( $name ) . '" data-attribute_name="attribute_' . esc_attr( sanitize_title( $attribute ) ) . '" data-show_option_none="' . ( $show_option_none ? 'yes' : 'no' ) . '">';
    $html .= '<option value="">' . esc_html( $show_option_none_text ) . '</option>';

    if ( ! empty( $options ) ) {
        if ( $product && taxonomy_exists( $attribute ) ) {
            $terms = wc_get_product_terms( $product->get_id(), $attribute, array( 'fields' => 'all' ) );

            foreach ( $terms as $term ) {
                if ( in_array( $term->slug, $options ) ) {
                    // HERE Added the function to get the stock text
                    $stock_text = get_variation_stock_text( $product, $name, $term->slug );

                    $html .= '<option value="' . esc_attr( $term->slug ) . '" ' . selected( sanitize_title( $args['selected'] ), $term->slug, false ) . '>' . esc_html( apply_filters( 'woocommerce_variation_option_name', $term->name ) . $stock_text ) . '</option>';
                }
            }
        } else {
            foreach ( $options as $option ) {
                $selected = sanitize_title( $args['selected'] ) === $args['selected'] ? selected( $args['selected'], sanitize_title( $option ), false ) : selected( $args['selected'], $option, false );
                // HERE Added the function to get the stock text
                $stock_text = get_variation_stock_text( $product, $name, $option );

                $html .= '<option value="' . esc_attr( $option ) . '" ' . $selected . '>' .
                esc_html( apply_filters( 'woocommerce_variation_option_name', $option ) . $stock_text ) . '</option>';
            }
        }
    }
    $html .= '</select>';

    endif;

    return $html;
}

// Change product availability text
add_filter( 'woocommerce_get_availability_text', 'filter_product_availability_text', 10, 2);
function filter_product_availability_text( $availability, $product ) {
    $stock = $product->get_stock_quantity();
    return $product->is_in_stock() ? $stock . ' ' . __("Skladem", "woocommerce") : __("Vyprodáno", "woocommerce");
}

Code goes in function.php file of your active child theme (or active theme). Tested and works.

Based on “How to add variation stock status to Woocommerce product variation dropdown“