【报Bug】开发模式页面正常渲染，发布之后的代码 页面空白

示例代码：

drawback() {  
                const _this = this  
                return function(index) {  
                    let drawbackValue = ''  
                    if (this.formData.car_detail[index].is_used_car == 1 && !_this.formData.car_detail[index].purchase_price || this.formData.car_detail[index].is_used_car == 0 && !_this.formData.car_detail[index].discount_amount) {  
                        return drawbackValue  
                    }  
                    // 计算公式：发票价格/1.13*0.13  
                    console.log('index---: ', index);  
                    if (_this.formData.car_detail[index].is_used_car == 1) {  
                        drawbackValue = _this.$digit.round( _this.$digit.times(_this.$digit.divide(_this.formData.car_detail[index].purchase_price, 1.13), 0.13), 0)  
                    } else{  
                        drawbackValue = _this.$digit.round( _this.$digit.times(_this.$digit.divide(_this.$digit.minus(_this.formData.car_detail[index].manufacturer_price, _this.formData.car_detail[index].discount_amount), 1.13), 0.13), 0)  
                    }  
                    _this.formData.car_detail[index].drawback = drawbackValue.toString()  
                    return drawbackValue  
                }  
            } 

操作步骤：

开发模式可以，发行之后不可以

预期结果：

页面正常展示

实际结果：

页面白屏