How to add a category programmatically to a WooCommerce product?

Question

In WooCommerce, if an item is sold out, I would like to add a category "sold out" to it, so that I can show these items in a separate section.

I created the "sold out" category in the WooCommerce/WordPress Admin panel.

This is what I have in my functions.php:

add_action( 'woocommerce_before_shop_loop_item_title', 'mytheme_display_sold_out_loop_woocommerce' );
 
function mytheme_display_sold_out_loop_woocommerce() {
    global $product;
 
    if ( !$product->is_in_stock() ) {
       // add category "sold out"   
    }
}

Now, how can I automatically add the category "sold out" to any sold out WooCommcerce product?

score 3 · Accepted Answer · answered Sep 13 '20 at 19:27

Assuming that the product category term name "sold out" exists, try the following:

add_action( 'woocommerce_before_shop_loop_item_title', 'mytheme_display_sold_out_loop_woocommerce' );
 
function mytheme_display_sold_out_loop_woocommerce() {
    global $product;

    $term_name = 'Sold out';

    // Get the product category term Id for "Sold out" term name
    $term_id   = get_term_by( 'name', $term_name, 'product_cat' )->term_id;
 
    // 1. Add product category "Sold out"
    if ( ! $product->is_in_stock() && ! has_term( $term_id, 'product_cat', $product->get_id() ) ) {
       // Get product categories (if there is any)
       $term_ids = (array) $product->get_category_ids();

       // Add the product category term Id for "Sold out" term name to $term_ids array
       $term_ids[] = $term_id;

       $product->set_category_ids( $term_ids ); // Update product categories
       $product->save(); // Save to database
    } 
    // 2. Remove product category "Sold out"
    elseif ( $product->is_in_stock() && has_term( $term_id, 'product_cat', $product->get_id() ) ) {
       // Get product categories (if there is any)
       $term_ids = (array) $product->get_category_ids();

       // Remove the product category term Id for "Sold out" term name in $term_ids array
       if ( ( $key = array_search( $term_id, $term_ids ) ) !== false ) {
           unset($term_ids[$key]);
       }

       $product->set_category_ids( $term_ids ); // Update product categories
       $product->save(); // Save to database
    }
}

Code goes in functions.php file of your active child theme (or active theme). It should work.

Now it should be lighter to use the term Id for "sold out" product category, so this way you could replace (in the code):

$term_name = 'Sold out';

// Get the product category term Id for "Sold out" term name
$term_id   = get_term_by( 'name', $term_name, 'product_cat' )->term_id;

by only the term id for 'Sold out' product category term name like (replace 19 by the real term Id):

$term_id = 19;

Thank you very much! This looks exactly like what I need. I will try your solution. :) — Cinder, Sep 15 '20 at 12:27

How to add a category programmatically to a WooCommerce product?

1 Answers1