Ecommerce methods in Matomo (Javascript)

Question:
In Matomo, which methods are available in Ecommerce to pass information to Matomo, from the data layer of the browser?

Answer:
In Matomo, to track Ecommerce data from the data layer of the browser, several JavaScript methods are available within the Matomo tracking API. These methods enable you to pass product and order-related information efficiently. Here's an overview of the key methods used for Ecommerce tracking:

### 1. **Ecommerce Tracking Methods**
   - **`trackEcommerceOrder(orderId, grandTotal, subTotal, tax, shipping, discount)`**
     - This method is used to track an order after a user completes a purchase. You should call this method with details such as the order ID, total amount, and any applicable taxes, shipping, and discounts.
     - **Parameters:**
       - `orderId`: Unique identifier for the order.
       - `grandTotal`: The total amount of the order (including tax, shipping, etc.).
       - `subTotal`: (Optional) Total value of the items in the order, excluding tax and shipping.
       - `tax`: (Optional) Total tax for the order.
       - `shipping`: (Optional) Shipping cost for the order.
       - `discount`: (Optional) Discount applied to the order.

   - **`addEcommerceItem(sku, name, category, price, quantity)`**
     - This method is used to add items to the cart or an order. Each item added is associated with details such as SKU, product name, category, price, and quantity.
     - **Parameters:**
       - `sku`: The unique identifier for the product (e.g., product code).
       - `name`: (Optional) The name of the product.
       - `category`: (Optional) Category name or hierarchy (e.g., "Clothing > Men > Shirts").
       - `price`: (Optional) Price of the product.
       - `quantity`: (Optional) Quantity of the product being purchased.

   - **`trackEcommerceCartUpdate(grandTotal)`**
     - This method is used to update the cart's total value. Call this whenever the cart's content changes (e.g., adding or removing products).
     - **Parameters:**
       - `grandTotal`: The updated total amount of the cart.

### 2. **Implementation Tips**
   - **Data Layer Integration**: To use these methods with data from a data layer (like in a tag management system), you typically access the data layer variables and pass the values to these methods.
   - **Order of Execution**: Ensure that `addEcommerceItem` is called before `trackEcommerceOrder` to associate all items with the order.
   - **Asynchronous Loading**: If using Matomo asynchronously, make sure that the data layer information is loaded and accessible before calling these methods.

### 3. **Example Usage**
```javascript
// Example: Tracking a purchase with multiple items
_paq.push(['addEcommerceItem',
    "12345", // SKU
    "Running Shoes", // Product name
    "Sports > Running", // Category
    99.95, // Price
    2 // Quantity
]);

_paq.push(['addEcommerceItem',
    "67890", // SKU
    "Running Shorts", // Product name
    "Sports > Running", // Category
    49.95, // Price
    1 // Quantity
]);

// Track the order
_paq.push(['trackEcommerceOrder',
    "ORDER123", // Order ID
    249.85, // Grand Total
    199.85, // Sub Total
    20.00, // Tax
    30.00, // Shipping
    0.00 // Discount
]);
```

These methods should be called in sequence based on the Ecommerce events occurring on your website, like adding items to the cart or completing a purchase.h
h
h