I’ve had the somewhat dubious pleasure of launching a new WordPress / WooCommerce site for an established collectables business. The site replaced an aging cart system, that was frankly a steaming pile. Almost every item sold by this business is unique so they wanted to default the values for Manage Stock to true and Sold Individually to true.

The WooCommerce Inventory Screen

It turns out the easiest way to do this is to add some javascript to the admin_enqueue_scripts action that checks the form elements we need checked. Poking about with the Chrome element inspector at the WooCommerce stock handling form told me we needed the _manage_stock and _sold_individually checkboxes ticked and to set a value in the _stock text field. Here’s the code I put in my child theme’s functions.php file.

//
//set default stock handling values
//

    add_action('admin_enqueue_scripts', 'wc_default_variation_stock_quantity');

    function wc_default_variation_stock_quantity()
    {
        global $pagenow, $woocommerce;

        $default_stock_quantity = 1;
        $screen = get_current_screen();

        if ( $pagenow == 'post-new.php' && $screen->post_type == 'product')
        {
            ?>
            <script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
            <script type="text/javascript">
                jQuery(document).ready(function () {
                    if (!jQuery('#_manage_stock').attr('checked')) {
                        jQuery('#_manage_stock').attr('checked', 'checked');
                    }
                    if ('0' === jQuery('#_stock').val()) {
                        jQuery('#_stock').val(<?php echo $default_stock_quantity; ?>);
                    }
                    if (!jQuery('#_sold_individually').attr('checked')) {
                        jQuery('#_sold_individually').attr('checked', 'checked');
                    }

                });
            </script>
            <?php
        }
    }

The code itself is fairly simple. The javascript is injected into the document.ready function but only if we’re adding a new post and the post type is WooCommerce’s product post type. The appropriate checkboxes have their checked attribute set to true and the _stock field is set to a value of 1 if it’s currently zero. Simples!