"use strict";

// *****************************************************************

// 操作数据属性

var person = {

    name: 'hugh',

    age: 29,

    sayName: function() { console.log(1); }

}

// 修改属性默认特性:Object.defineProperty()

Object.defineProperty(person, "name", {

    writable: true,

    value: 'dong',

    configurable: false,

    enumerable: false

});

console.log(person);

// *****************************************************************

// 操作访问器属性

var book = {

    _year: 2004, // _作为标记只能通过对象访问的属性

    edition: 0

};

Object.defineProperty(book, "year", {

    // 访问器属性year包含setter和getter函数

    get: function() {

        return this._year;

    },

    set: function(newValue) {

        this._year = newValue;

        this.edition = newValue - 2004;

    }

})

book.year = 2008;

console.log(book);

console.log(book.edition);

// 旧方法,ie8部分不支持defineProperty()

// 严格模式不可用

// book._defineGetter_("year",function(){

//     return this._year;

// });

// book._defineSetter_("year",function(newValue){

//     this._year = newValue;

//     this.edition = newValue - 2014;

// });

// *****************************************************************

// 定义多个属性

var book2 = {};

Object.defineProperties(book2, {

    // 数据属性

    _year: {

        value: 2004,

        writable: false,

        enumerable: false,

        configurable: true

    },

    edition: {

        value: 0,

        writable: false,

        enumerable: false,

        configurable: true

    },

    // 访问器属性

    year: {

        get: function() {

            return this._year;

        },

        set: function(newValue) {

            this._year = newValue;

            this.edition = newValue - 3000;

        }

    }

});

console.log(book2);

// *****************************************************************

// 查看属性的属性

console.log(Object.getOwnPropertyDescriptor(book2,'_year'));

console.log(Object.getOwnPropertyDescriptor(book2,'edition'));

console.log(Object.getOwnPropertyDescriptor(book2,'year'));