super关键词

super

super通常用语继承中，例如：

class Node{
    constructor(element){
        this.element = element
        this.next = undefined
    }
    log(){
        console.log("test")
    }
}

class DoubleNode extends Node{
    constructor(element){
        super(element)
        this.prev = undefined
    }
    log(){
        console.log("test2")
    }
    test(){
        this.log()
        super.log()
    }
}

构造函数中：

super相当于吧父类的constructor执行了，并将this转为子类的实例，super中传递的实参实际是给父类传递的

constructor(element){
    super(element)
    this.prev = undefined
}

还可通过super调用父类的原形方法:

node = new DoubleNode(1)
node.test()

结果为

test2

test