Ajax add to cart capturing booking line item properties

bta-ajax.js

function addToCart(e){
  if (typeof e !== 'undefined') e.preventDefault();
  
  if (!$('form[action="/cart/add"]').valid()) {
    return;
  }
  
  var form = $(this).parents('form'), 
      data = [];
      
  data.push(["id", form.find('[name="id"]').val()].join('='));
  data.push(["quantity", form.find('[name="quantity"]').val() || 1].join('='));
  if (form.find('[name="properties[booking-start]"]').length > 0) {
    data.push(["properties[booking-start]", bta.toLocalIsoString(form.find('[name="properties[booking-start]"]').datepicker('getDate'), false)].join('='));
    data.push(["properties[booking-finish]", bta.toLocalIsoString(form.find('[name="properties[booking-finish]"]').datepicker('getDate'), false)].join('='));
  }

  $.ajax({ 
    type: 'POST',
    url: '/cart/add.js',
    async: false, 
    cache: false, 
    data: data.join('&'),
    dataType: 'json',
    error: addToCartFail,
    success: addToCartSuccess
  });
}