Chapter6_OO_1.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>面向对象设计</title>
</head>
<body>
<script type="text/javascript">
    //////////////数据属性////////////////////////
    var person=new Object();
    person.name="John";
    person.age=19;
    person.sayname=function ( s) {
        console.log(s);
    }

    var ps2={};ps2.name="Niko";ps2.age=18;

    var ps3={name:"Niko",age:18};

    //定义属性不可更改
    Object.defineProperty(person,"name",{
        writable:false
    })
    person.name="NEW JOHN"
    console.log(person.name)


//不可删除属性
    Object.defineProperty(person,"name",{
        configurable:false,
        value:"Nicholas"
    })
    console.log(person.name)

    // 一旦把属性定义为不可配置的，
// 就不能再把它变回可配置了。
    // delete person.name
    // Object.defineProperty(person,"name",{
    //     configurable:true,//error
    //     value:"Nicholas"
    // })

    //所有方法
    Object.defineProperty(ps2,"age",{
        configurable:false,
        enumerable:false,
        writable:false,
        value:28
    })
    //enumerable=false 所以只有一个属性输出
    for (var i in ps2){
        console.log(ps2[i])
    }

    ///////访问器属性/////////////////////
    var book={};
    book._year=2004;
    book.edition=1;

    Object.defineProperty(book,"year",{
        get:function () {
            return this._year;
        },
        set:function (newValue) {
            if(newValue>2004){
                this._year=newValue;
                this.edition+=1;
            }
        }
    });
    book.year=2005;
    console.log(book._year)
    console.log(book.edition)

    /////Object.defineProperties()/////////////////
    book={};
    Object.defineProperties(book,{
        _year:{
            value:2004
        },
        edition:{
            value:1
        },
        year:{
            get:function () {
                return this._year
            },
            set:function (v) {
                this._year=v;
            }
        }
    })

    ////////////////Object.getOwnPropertyDescriptor()///////////////////////
    var op = Object.getOwnPropertyDescriptor(book,"_year");
    console.log(op.configurable)
    console.log(op.value)
    console.log(typeof op.get)

    var op2 = Object.getOwnPropertyDescriptor(book, "year");
    console.log(op2.get)
    console.log(op2.value)
    console.log(typeof op2.get)
</script>
</body>
</html>