gistfile1.js

    module.PosWidget = module.PosWidget.extend({
    	build_widgets: function() {
            var self = this;
            this._super();
            this.discount_card_widget = new module.PaymentScreenDiscountWidget(this, {});
            this.discount_card_widget.replace($('.placeholder-PaymentScreenDiscountWidget'));
            
            },
    
    });

    module.Order = module.Order.extend({

    getTotalCardDiscount: function() {
    var subtotal = (this.get('orderLines')).reduce((function(sum, orderLine) {
      return sum + orderLine.get_price_with_tax();
    }), 0);

    var discount_id = self.$('#discount-card-select').val();
    if (discount_id) {
      var discount_card = new module.PaymentScreenDiscountWidget(this, {});

      var discount_promise = discount_card
        .fetch('pos.discount.cards', ['type', 'value'], [
          ['id', '=', discount_id]
        ]).then(function(discount) {
          var type = discount[0].type;
          var value = discount[0].value;
          if (type === 'fi') {
            discount = value;
          } else {
            discount = (subtotal * value) / 100;

          }
          return discount;
        });
    } else {
      discount_promise = Promise.resolve(0);
    }
    
    return discount_promise.then(function(discount) {
      return discount;
    });
    // need to return discount
  },


     getTotalTaxIncluded: function() {
        this.getTotalCardDiscount().then(function(discount){
            console.log("returned discount..............",discount)
            return discount
        }) 
        return 100 ;




        
    },

});