Create Checkout Line Items Array in Shopify

Introduction

When customizing your Shopify store’s checkout process, you may find yourself needing to create an array of objects containing detailed information about each item in the customer’s order. This can be particularly useful for tracking purposes, enhancing the user experience, or integrating with third-party services. In this guide, we’ll explore how to accomplish this task efficiently and effectively.

Understanding the Challenge

The Desired Outcome

Before diving into the solution, let’s clarify what we’re trying to achieve. The goal is to create an array of objects on the checkout page, where each object represents a line item in the order and contains various properties such as product ID, size, variant ID, URL, image URL, color, unit price, quantity, and gender.

The Data Source

The primary source of data for this task is the checkout.line_items object provided by Shopify. This object contains all the necessary information about each item in the current order.

The Implementation Hurdle

While accessing individual values from checkout.line_items is straightforward, the challenge lies in organizing this data into an array of objects that can be easily manipulated and used in JavaScript.

The Solution: Combining Liquid and JavaScript

The Recommended Approach

The most effective way to create this array of objects is by using a combination of Liquid (Shopify’s templating language) and JavaScript. This method allows us to leverage Liquid’s access to Shopify’s data while creating a JavaScript array that can be used for further processing or integration with other scripts.

Step-by-Step Implementation

1. Initialize the JavaScript Array

First, we need to create an empty JavaScript array that will hold our objects:

var items = [];

2. Loop Through Line Items with Liquid

Next, we’ll use Liquid to iterate through each line item in the checkout:

{% for line_item in checkout.line_items %}
  // Our JavaScript code will go here
{% endfor %}

3. Extract Item Properties

Within the Liquid loop, we’ll extract specific properties for each item. Some properties, like size and color, may be stored as options:

{% for option in line_item.options_with_values %}
  {% if option.name == 'Size' %}
    {% assign size = option.value %}
  {% endif %}
  {% if option.name == 'Color' %}
    {% assign color = option.value %}
  {% endif %}
{% endfor %}

4. Create and Populate the JavaScript Object

Now, we’ll create a JavaScript object for each line item and populate it with the extracted data:

var item = {};
item.productId = "{{line_item.product_id}}";
item.size = "{{size}}";
item.variantId = "{{line_item.variant_id}}";
item.url = "{{line_item.url}}";
item.imageUrl = "{{line_item.image}}";
item.color = "{{color}}";
item.unitPrice = {{line_item.original_price}};
item.quantity = {{line_item.quantity}};
item.currency = "JPY";
item.gender = "NA";

5. Add the Object to the Array

Finally, we’ll push the newly created object into our items array:

items.push(item);

The Complete Code

Putting it all together, here’s the complete code snippet that creates the desired array of objects:

<script>
var items = [];
{% for line_item in checkout.line_items %}
  {% for option in line_item.options_with_values %}
    {% if option.name == 'Size' %}
      {% assign size = option.value %}
    {% endif %}
    {% if option.name == 'Color' %}
      {% assign color = option.value %}
    {% endif %}
  {% endfor %}
  var item = {};
  item.productId = "{{line_item.product_id}}";
  item.size = "{{size}}";
  item.variantId = "{{line_item.variant_id}}";
  item.url = "{{line_item.url}}";
  item.imageUrl = "{{line_item.image}}";
  item.color = "{{color}}";
  item.unitPrice = {{line_item.original_price}};
  item.quantity = {{line_item.quantity}};
  item.currency = "JPY";
  item.gender = "NA";
  items.push(item);
{% endfor %}
</script>

Considerations and Best Practices

Refreshing Data

It’s important to note that when using this method, the page must be refreshed to update the JavaScript array. If you need real-time updates without page refreshes, consider using AJAX or a library like CartJS.

Error Handling

While not shown in the example above, it’s good practice to include error handling in your code. This could involve checking if properties exist before assigning them and providing default values where appropriate.

Performance

For stores with a large number of line items, be mindful of the performance impact of creating complex objects for each item. If performance becomes an issue, consider optimizing your code or limiting the amount of data stored for each item.

Advanced Techniques

Using CartJS for Dynamic Updates

For more advanced implementations that require dynamic updates without page refreshes, consider using CartJS. This library provides a more robust way to interact with the cart and its items in real-time.

Customizing for Specific Needs

The example provided uses a fixed structure for the item objects. Depending on your specific requirements, you may need to modify this structure. For instance, you might need to include additional properties or format certain values differently.

Conclusion

Creating an array of objects on Shopify’s checkout page is a powerful way to organize and manipulate order data. By combining Liquid’s access to Shopify’s data with JavaScript’s flexibility, you can create a versatile solution that meets your specific needs. Remember to consider performance, error handling, and the potential need for real-time updates when implementing this solution in your Shopify store.