Javascript (ES8) -从父类获取类的静态值

Question

我有一个类Parent (使用class声明定义，但我知道这主要是语法糖)，以及扩展它的多个类(Child1、Child2等)。子类有一个分配给它们的静态属性(除了它们的声明之外--据我所知，没有办法在类声明中分配静态属性)。

我想从父类访问任何子类的静态值，比如在方法getStaticValue()中。

class Parent {
    constructor() {
        //Do parent stuff
    }

    getStaticValue() {
        return "The value of staticValue is " + this.staticValue;
    }
}

class Child1 extends Parent {
    constructor() {
        super();
        //Do child1 stuff
    }
}
Child1.staticValue = "Child1";

class Child2 extends Parent {
    constructor() {
        super();
        //Do child2 stuff
    }
}
Child2.staticValue = "Child2";

我想从父类中访问任意子类的staticValue值，但是尝试像上面写的那样做时总是返回未定义的。换言之：

let parentStaticValue = new Parent().getStaticValue();
//Desired output = "The value of staticValue is undefined"
//Actual output = "The value of staticValue is undefined"

let child1StaticValue = new Child1().getStaticValue();
//Desired output = "The value of staticValue is Child1"
//Actual output = "The value of staticValue is undefined"

let child2StaticValue = new Child2().getStaticValue();
//Desired output = "The value of staticValue is Child2"
//Actual output = "The value of staticValue is undefined"

是否有一种方法可以从父类访问子类的静态值，而不必在每种情况下都知道子类的名称？

Answer 1

可以在子类中使用超级()将静态值传递给父构造函数：

class Parent {
    constructor(childStaticValue) { // receive the value from the children class
        this.staticValue = childStaticValue // and assign it to the local variable
    }

    getStaticValue() {
        return "The value of staticValue is " + this.staticValue;
    }
}

class Child1 extends Parent {
    constructor() {
        super(Child1.staticValue); // pass the value to the parent class
        //Do child1 stuff
    }
}
Child1.staticValue = "Child1";

class Child2 extends Parent {
    constructor() {
        super(Child2.staticValue); // pass the value to the parent class
        //Do child2 stuff
    }
}
Child2.staticValue = "Child2";