Order Summary Knockout.js how is work?

Question

Hi I am focusing the Order Summary on my shopping cart, I found below file

/magento/module-checkout/view/frontend/web/template/summary/item/details.html

Inside above, there has a line of code, how does below works to grab the value?

<span class="label"><!-- ko i18n: 'Qty' --><!-- /ko --></span>

where should I start to check the code which generate qty of the items in the Shopping cart - order summary block?

Thanks

Answer 1

Check this file:

vendor/magento/module-checkout/view/frontend/web/js/view/configure/product-customer-data.js

/**
    * Updates product's qty input value according to actual data
    */
    updateQty = function () {

        if (productQty || productQty === 0) {
            productQtyInput = productQtyInput || $(selectors.qtySelector);

            if (productQtyInput && productQty.toString() !== productQtyInput.val()) {
                productQtyInput.val(productQty);
            }
        }
    },

    /**
    * Sets productQty according to cart data from customer-data
    *
    * @param {Object} data - cart data from customer-data
    */
    setProductQty = function (data) {
        var product;

        if (!(data && data.items && data.items.length && productId)) {
            return;
        }
        product = _.find(data.items, function (item) {
            if (item['item_id'] === itemId) {
                return item['product_id'] === productId ||
                    item['item_id'] === productId;
            }
        });

        if (!product) {
            return;
        }
        productQty = product.qty;
    };

    cartData.subscribe(function (updateCartData) {
        setProductQty(updateCartData);
        updateQty();
    });

    setProductQty(cartData());
    updateQty();