How Cart Labels Work
The PreOrder Now app adds a hidden line item property field to the "Add to Cart" form. This field contains the cart label used to identify preorder products in the cart and on the order.
If that hidden field is missing or not passed to the cart along with the product, then the cart label will not appear.
Diagnosing the Problem
To troubleshoot missing cart labels:
Check all the ways customers can add products to the cart, and not just from product pages.
Confirm that our hidden line item property field is present in each case.
Make sure this field is actually being sent to the cart. Some custom JavaScript (JS) or AJAX add-to-cart functions ignore hidden fields.
Common Causes
Cart labels don’t interact with our server, so this is always a frontend issue. Below are common causes:
AJAX or JavaScript Add-to-Cart Functions
Many custom AJAX or JS scripts skip hidden line item properties. If your theme or a third-party app uses this method, the label won’t be added.
Add-to-Cart Buttons Outside the Product Page
Example: Add-to-cart buttons on homepages, collection pages, or quick views. If our app isn’t running on those buttons, the label won't be added—especially if they're using AJAX.
Product Added to Cart Before Preorder Was Enabled
If a shopper added an item to their cart before it became a preorder product, the label wouldn't have been included.
Third-Party Upsell or Product Recommendation Apps
Apps like upsell popups or post-purchase offers often add products to the cart without going through the product page, skipping our hidden label field.
Sales Channels That Bypass Product Pages
Products added through channels like the Facebook Shop or Instagram may not include the label.
App Didn’t Finish Loading Before Add-to-Cart
If shoppers click “Add to Cart” before the PreOrder Now app finishes loading, the hidden field might not be added yet.
What You Can Do
Check every touchpoint where customers can add products to the cart.
Ensure your theme and any third-party scripts or apps fully support Shopify’s line item properties.
Consider asking your developer to update any custom add-to-cart functions to include hidden fields.
If you’re using upsell or cart-related apps, check with their support to confirm compatibility with line item properties.