javascript - 覆盖父类实例(非静态)方法javascript

Question

我的用例是 React，但这是一个 JavaScript 问题。

我想通过使用子类来扩展 componentWillMount 的功能。我怎样才能做到这一点？

class Super {
    componentWillMount() {
        doStuff()
    }
}
class Sub extends Super {
    componentWillMount() {
        super() // this doesn't work
        doMoreStuff()
    }
}

Answer 1

使用的语法是:

super.componentWillMount()

来自 mdn :

The super keyword is used to call functions on an object's parent.

The super.prop and super[expr] expressions are valid in any method definition in both classes and object literals.

Syntax

super([arguments]); // calls the parent constructor.
super.functionOnParent([arguments]);

演示:

class Super {
    componentWillMount() {
        console.log('parent')
    }
}

class Sub extends Super {
    componentWillMount() {
        super.componentWillMount()
        console.log('child')
    }
}

new Sub().componentWillMount();