data-cart-add API should support sending a quantity, and potentially line item properties as well.

[gavinballard]

Could be done simply through the use of a data-cart-quantity and data-cart-* attributes.

[lmartins]

@gavinballard is this currently available? Was looking for a way to display product customisation options (https://help.shopify.com/themes/customization/products/get-customization-information-for-products) and can't seem to find it anywhere in the data retrieved by the API.

[gavinballard]

@lmartins The data-cart-quantity attribute is supported, but line item properties aren't I'm afraid. Currently, the way to do this would be to make your entire add form Ajaxable by adding a data-cart-submit attribute to the wrapping form, or by capturing the relevant event in Javascript and using the CartJS API:

<button id="custom-add-buttons">Add</button>
<script>
  $('#custom-add-button').click(function() {
    CartJS.addItem(123, 2, {
      property1: 'value1'
    })
  });
</script>