cart/line/update

Fields

LineItems Fields

id • [ string ]required

The Shopify ID of the variant to add

variantId • [ string ]

The Shopify ID of the variant to add

quantity • [ number ]

Quantity of variants associated with the line item

sellingPlanId • [ string ]

The Shopify Selling Plan ID for adding a subscription to cart

attributes • [ array ]

An array of Key Value objects that store additional information to the lineItem

Updates existing line items in the cart by modifying their quantity, variant, attributes, or selling plan. This action supports partial updates - only the fields you provide will be changed, while other properties remain unchanged.

Basic usage - Updating the quantity of a line item

Tapcart.action("cart/lineItem/update", {
  lineItems: [
    {
      id: "gid://shopify/CartLine/123456789",
      quantity: 3
    }
  ]
});

Basic usage - Updating lineItem attributes

Tapcart.action("cart/lineItem/update", {
  lineItems: [
    {
      id: "gid://shopify/CartLine/123456789",
      attributes: [
        {
          key: "color_preference",
          value: "blue"
        }
      ]
    }
  ]
});

Advanced Usage - Updating multiple lineItems with various updates

Tapcart.action("cart/lineItem/update", {
  lineItems: [
    {
      id: "gid://shopify/CartLine/123456789",
      quantity: 2,
      attributes: [
        {
          key: "color_preference",
          value: "blue"
        }
      ]
    },
    {
      id: "gid://shopify/CartLine/987654321",
      variantId: "gid://shopify/ProductVariant/11111",
      sellingPlanId: "gid://shopify/SellingPlan/22222"
    }
  ]
});