Amazon Fresh demonstrating how not to do it

amazon-fresh.js

function updateAddAllToCartButton(event) {
    var validList = "";
    var invalidList = "";
    
    jQuery(".listItem").each(function(index) {
        var item = jQuery(this); 
        var conflictInput = item.find("input[name='conflictWithSlot']");
        if (item.find(".itemUnavailableText").size() > 0 || item.find(".discontinued").size() > 0) {
            // Ignore unavailable and discontinued items
        } else if (conflictInput.size() == 0 || conflictInput.val() == "false") { // skip invalid items
            var quantity = item.find(".addToCart input[name='quantity']");
            
            if (quantity.size() > 0) {
                var asin = item.attr("id");
                var merchantId = item.find(".addToCart input[name='merchantId']").val();
                validList += asin + "|" + quantity.val() + "|" + merchantId + ",";
            }
        } else {
          invalidList +="<li>" + item.find(".itemTitle a").html() + "</li>";
        }
    });
    jQuery(this).find("input[name='itemDetails']").val(validList);

    // show message if invalid items cannot be added
    if (warnOfInvalidItems && invalidList != "") {
        event.preventDefault();
        var message = "These items are not available for delivery <strong>" + jQuery("#headerNav #selectday a").html() + "</strong> and will NOT be added to your cart:<ul>";
        
        message += invalidList;
        message +="</ul>";
        message += "<button id='addAllAvailableItemsToCart'>Continue without These Items</button>&nbsp;&nbsp;";
        message += "<button class='nevermind'>Nevermind</button/>";
        
        showOnDemandLightboxWithContent(message, jQuery(this));
        
        jQuery("#addAllAvailableItemsToCart").click(function() {
            warnOfInvalidItems = false;
            jQuery("#addAllToCart").submit();
            hideLightbox();
        });
    }
    
    warnOfInvalidItems = true;
}