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JavaScript ??? Class ??

????

? JavaScript ?????????? Object ???????????????????????Object.prototype ???????????

var Student = {
    name: "studentName",
    age: 18,
    run: function() {
        console.log(this.name + " run...");
    }
};
var xiaoming = {
    name: "xiaoming"
};
// xiaoming ???? Student
xiaoming.__proto__ = Student;
xiaoming.run(); // xiaoming run...
console.log(xiaoming.age); // 18

Class ???ES6?

class ???? ES6 ?????????????????????????

// ???
class Student {
    constructor(name) {
        this.name = name;
    }
    hello() {
        alert('hello');
    }
}
// ???
class XiaoStudent extends Student {
    constructor(name, grade) {
        super(name); // ????????
        this.grade = grade;
    }
    myGrade() {
        alert("?????");
    }
}
// ????
var xiaoming = new Student("xiaoming");
xiaoming.hello(); // hello
var xiaohong = new XiaoStudent("xiaohong", 80);
xiaohong.myGrade(); // ?????

???

__proto__ ??????????????????? JavaScript ??????????

console.log(xiaoming.__proto__); // ?? Student ??
console.log(Student.__proto__); // ?? Object ??

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