javascript - ES6 类通过 mixins 进行多重继承

我正在尝试使用 mixins 来理解 ES6 多重继承。

我正在关注 this article (简单的 mixins)。但是当我运行代码时，我的输出是:

main

Uncaught ReferenceError: this is not defined ,
并且错误再次指向 console.log('main')

我在最新版本的 Chrome 上运行它。这是我的代码:

const RaceDayService = superclass => class extends superclass {
    constructor(){
        console.log('service');
    }
}

const RaceDayDB = superclass => class extends superclass {
    constructor(){
        console.log('db');
    }
}

class RaceDayUI {
    constructor(){
        console.log('ui');
    }
}

class RaceDay extends RaceDayDB(RaceDayService(RaceDayUI)){
    constructor(options){
        console.log('main');
    }
}

const raceDay = new RaceDay();

关于我做错了什么的任何想法？

谢谢!

最佳答案

如果父类(super class)包含构造函数，则必须在子类的构造函数中调用 super() 方法:

const RaceDayService = superclass => class extends superclass {
    constructor(){
        super();
        console.log('service');
    }
}

const RaceDayDB = superclass => class extends superclass {
    constructor(){
        super();
        console.log('db');
    }
}

class RaceDayUI {
    constructor(){
        console.log('ui');
    }
}

class RaceDay extends RaceDayDB(RaceDayService(RaceDayUI)){
    constructor(options){
        super();
        console.log('main');
    }
}

const raceDay = new RaceDay();

关于javascript - ES6 类通过 mixins 进行多重继承，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/44703071/