Enable Automatic Quantity Updates in PHP Cart

By default, the cart page requires users to click "Update Shopping Cart" after changing item quantities. This conservative UI prioritizes simplicity in Hyvä.

To enable automatic (Ajax-based) quantity updates, customize the `Magento_Checkout/templates/php-cart/item/default.phtml` template.

Add the following event listener to the quantity input field. This will automatically submit the form two seconds after a visitor changes the quantity:

x-on:change.debounce.2000ms="$event.target.form && $event.target.form.dispatchEvent(new Event('submit', { cancelable: true }));"

Here is the full input field code for reference:

<input
    id="cart-<?= $escaper->escapeHtmlAttr($item->getId()) ?>-qty"
    name="cart[<?= $escaper->escapeHtmlAttr($item->getId()) ?>][qty]"
    value="<?= $escaper->escapeHtmlAttr($block->getQty()) ?>"
    type="number"
    size="4"
    step="any"
    title="<?= $escaper->escapeHtmlAttr(__('Qty')) ?>"
    class="qty form-input px-2 py-2 w-20 text-center"
    required
    min="0"
    @change.debounce.2000ms="$event.target.form && $event.target.form.dispatchEvent(new Event('submit', { cancelable: true }));"
    data-role="cart-item-qty"
>

Using `dispatchEvent` on the form triggers JavaScript submission events, including `hyva.postCart`, which reloads cart data via Ajax without a full page refresh.

If you prefer not to use Ajax but still want automatic quantity updates, use this instead:

x-on:change.debounce.2000ms="$event.target.form.submit()"