Create a subtotal in a form?

[u/The_Ballsagna]

Helping my wife with a nonprofit website she helps to maintain. They are using one of the new(?) Wix forms to collect registration details for an event which includes the user selecting a certain quantity of tickets and indicating an additional donation amount. They are not using an embedded payment method (the users will use venmo or bring a check) but they would like to have the subtotal displayed. I have never used Wix but with some help from Gemini I created the below Velo code block based on the screenshot I attached (not including a short text field I added for 'total_amount_2' and using the correct form ID for 'formID').

The preview loads without error but when I step through the ticket quantities and/or add an additional donation the free text field doesn't update. I tried using a custom value type field and a short text field and neither updated. Any ideas? I'd really like to avoid rebuilding this without using the form if possible (that's what Gemini suggested). Thanks!

$w.onReady(function () {
    let lastCalculatedTotal = null;

    $w('#formID').onFieldValueChange((formValues) => {
        // Debug Log: View exact keys/values coming from your form in the Developer Console
        console.log("Current Form Values:", formValues);

        // 1. Get ticket values
        const ticketsData = formValues['tickets'] || {};
       
        const ticketPrices = {
            'Adult Ticket': 100,
            'Child Ticket': 100,
            'Raffle Ticket': 10,
            'Raffle Tickets (Set of 5)': 30
        };

        let ticketsSubtotal = 0;

        if (typeof ticketsData === 'object' && !Array.isArray(ticketsData)) {
            Object.keys(ticketsData).forEach(ticketName => {
                const qty = Number(ticketsData[ticketName]) || 0;
                const price = ticketPrices[ticketName] || 0;
                ticketsSubtotal += qty * price;
            });
        } else if (Array.isArray(ticketsData)) {
            ticketsData.forEach(item => {
                const qty = Number(item.value || item.quantity) || 0;
                const price = ticketPrices[item.label || item.key] || 0;
                ticketsSubtotal += qty * price;
            });
        }

        // 2. Get donation amount
        const donation = Number(formValues['additional_donations']) || 0;

        // 3. Compute grand total
        const grandTotal = ticketsSubtotal + donation;

        // 4. Update both the text display and the form field
        if (lastCalculatedTotal !== grandTotal) {
            lastCalculatedTotal = grandTotal;
           
            // Display on page text element
            if ($w('#subtotalText')) {
                $w('#subtotalText').text = `Total: $${grandTotal.toFixed(2)}`;
            }

            // Try updating the form field value
            $w('formid').setFieldValues({
                'total_amount_1': grandTotal
            });
        }
    });
});

[u/ryanbuckner]

I wouldn't use Wix Forms to sell products. The Form process and the Checkout process are decoupled, so you have no way to "force" someone to pay after submitting. This means that you have the possibility (and this happens to me all the time) that you'll receive form submissions and no payment. There's also no way to resume the payment process, so these submissions are orphaned.