设计模式装饰模式

装饰模式是为类添加额外的职责。在我看来，这些职责并不是某一个类特有，需要添加的类都可以添加，每个类没有必要单独添加这个职责。

下面是我用js实现的装饰模式

var Employee={
    name: '',
    getName: function(){
        return this.name;
    },
    setName: function(name){
        this.name = name;
    },
    work: function(){}
}

function CosmeticsSalesEmployee(name){
    this.name = name;
    this.work = function(){
        alert(this.getName() + " 开始销售化妆品！");
    }
}

function FruitSalesEmployee(name){
    this.name = name;
    this.work = function(){
        alert(this.getName() + " 开始销售水果！");
    }
}

CosmeticsSalesEmployee.prototype = Employee;
FruitSalesEmployee.prototype = Employee;

var cosmeticsSalesEmployee1 = new CosmeticsSalesEmployee("小王");
cosmeticsSalesEmployee1.work();
//输出： 小王 开始销售化妆品
var fruitSalesEmployee = new FruitSalesEmployee("小张");
fruitSalesEmployee.work();
//输出   小张 开始销售水果

//装饰类
var Decorator = {
    employee: null,
    setEmployee: function(e){
        this.employee = e;
    },
    getEmployee: function(){
        return this.employee;
    },
    getName: function(){
        return this.employee ? this.employee.getName() : undefined;
    },
    work: function(){
        this.employee && this.employee.work();
    }
}

function ArrangeGoodDecorator(employee){
    Decorator.setEmployee(employee);
    this.work = function(){
        alert(this.getName() + "开始清扫货架！");
        Decorator.work();
    }
}
ArrangeGoodDecorator.prototype = Decorator;
var employee1 = new ArrangeGoodDecorator(new CosmeticsSalesEmployee("小王"));
employee1.work();
//输出：

//小王开始清扫货架！

//小王 开始销售化妆品！

var employee2 = new ArrangeGoodDecorator(new FruitSalesEmployee("小张"));
employee2.work();

//小张开始清扫货架！

//小张 开始销售水果！