相当于使用 __proto__?

Question

我正在尝试将显示模块模式与继承一起使用。我似乎让它工作正常，但它使用“__proto__”，我知道它被认为已弃用。有没有更好的方法是在不使用“__proto__”的情况下创建继承？

var Person = (function() {
    var _name;
    var api = {
        init: init,
        getName: getName
    }
    return api;

    function init(name) {
        _name = name;
    }

    function getName() {
        return _name;
    }
}())

var Teacher = (function() {
    var _subject = "Math";
    var api = {
        getSubject: getSubject,
        say: say
    }
    api.__proto__ = Person;
    return api;

    function getSubject() {
        return _subject;
    }

    function say() {
        console.log("I am " + this.getName() + " and I teach " + _subject)
    }
}());

Teacher.init("Bob");
Teacher.say() //  I am Bob and I teach math

https://plnkr.co/edit/XbGx38oCyvRn79xnn2FR?p=preview

Answer 1

直接的等价物——设置原型，仍然是个坏主意——是Object.setPrototypeOf：

Object.setPrototypeOf(api, Person);

不过，使用Object.create 基于原型创建对象然后向其添加属性的常规方法在这里可以正常工作：

var api = Object.create(Person);
api.getSubject = getSubject;
api.say = say;

但理想情况下，您应该只使用构造函数：

class Person {
    constructor(name) {
        this._name = name;
    }

    getName() {
        return this._name;
    }
}

class Teacher extends Person {
    constructor(name) {
        super(name);
        this._subject = 'Math';
    }

    getSubject() {
        return this._subject;
    }

    say() {
        console.log(`I am ${this.getName()} and I teach ${this.getSubject()}`);
    }
}

var teacher = new Teacher('Bob');
teacher.say() //  I am Bob and I teach math

没有 ES6：

function Person(name) {
    this._name = name;
}

Person.prototype.getName = function () {
    return this._name;
};

function Teacher(name) {
    Person.call(this, name);
    this._subject = 'Math';
}

Teacher.prototype = Object.create(Person.prototype);

Teacher.prototype.getSubject = function () {
    return this._subject;
};

Teacher.prototype.say = function () {
    console.log('I am ' + this.getName() + ' and I teach ' + this.getSubject());
};

var teacher = new Teacher('Bob');
teacher.say();  // I am Bob and I teach math