code: function extractCheckoutOptions(props) {
    var options = [
      props.paymentMethod,
      props.shippingMethod
    ];
  
    // Remove all nulls, empty strings, zeroes, and join with commas.
    var valid = select(options, function(e) {return e; });
    return valid.length > 0 ? valid.join(', ') : null;
  }
docs: Extracts checkout options.
  
  @api private
  @param {Object} props
  @return {string|null}