Adding a notice on Cart and checkout page based on item custom field highest value

Question

I have a a custom field value for each product. This custom field is inserted with the code below :

Answer 1

Here is a custom function that will display a message on cart and checkout (before coupon notice) pages with the highest number of days of manufacture…

Here is the code:

add_action('woocommerce_before_cart', 'days_of_manufacture');
add_action('woocommerce_before_checkout_form', 'days_of_manufacture', 5);
function days_of_manufacture() {
        $day_txt = ' ' . __('day', 'your_theme_domain_slug' );
        $days_txt = ' ' . __('days', 'your_theme_domain_slug' );
        $text = __('Your Order will be produced in: ', 'your_theme_domain_slug' );
        $max_days = 0;

        foreach( WC()->cart->get_cart() as $cart_item )
            if($cart_item['days_manufacture'] > $max_days)
                $max_days = $cart_item['days_manufacture'];

        if($max_days != 0) {
            if ($max_days == 1)
                $days_txt = $day_txt;

            $output = $text . $max_days . $days_txt;
            echo "<div class='woocommerce-info'>$output</div>";
        }
}

This code goes in function.php file of your active child theme (or theme) or also in any plugin file.

This code is tested and works.

Answer 2

Store the variable in the $_SESSION, then loop thru them and pick the highest, so you can use it later anywhere in your code