模式学习(五)--装饰者模式

function Sale(price){
        this.price = price || 100;
        this.decorators_list = [];// 装饰着列表作为自身的属性
    }

    // 追加列表
    Sale.prototype.decorate = function(decorator){
        this.decorators_list.push(decorator);
    };

    // getPrice 完成所有工作
    Sale.prototype.getPrice = function(){
        var price = this.price,
            i,
            max = this.decorators_list.length,
            name;
        
        console.log("初始price:", price, "有几个装饰者：", max);// 100   3

        for(i = 0; i < max; i++){
            console.log("每次单独的初始price:", price);//  100  105  112.875
            name = this.decorators_list[i];
            console.log("names are as follows::", name);

            price = Sale.decorators[name].getPrice(price);
            console.log("every step , this price is changing:",price)
        }
        return price;
    };

    Sale.decorators = {};// 子类  decorators 是一个object

    Sale.decorators.fedtax = {//  子子类
        getPrice : function(price){
            return price + price * 5 / 100;
        }
    };

    Sale.decorators.quebec = {
        getPrice : function(price){
            return price + price * 7.5 / 100;
        }
    };

    Sale.decorators.money = {
        getPrice : function(price){
            return "$" + price.toFixed(2);
        }
    };

    var sale = new Sale(100);
    sale.decorate('fedtax');
    sale.decorate('quebec');
    sale.decorate('money');
    var a = sale.getPrice();
    console.log(a);

说明：

　　上面是使用列表实现装饰者模式的。