class Person { constructor(name, age) { this.name = name this.age = age } test() { } }class Student extends Person { constructor(name, age, no) { super(name, age) this.no = no } say() { console.log(`name: ${this.name}, age: ${this.age}, no: ${this.no}`) } }let student = new Student('mrcode', 21, '11403080435') student.say()
student可以访问test方法,这点可以理解。 但是为什么通过Student中的this可以访问到父类中的name, age呢? ES6中的class只是原型链的语法糖。 原型链上的对象都是原型。 哪里来的name, age属性呢?
Why can the instance properties of a subclass in JS access the instance properties of the parent class? -PHP Chinese Q&A-Why can the instance attributes of a subclass in JS access the instance attributes of the parent class? -PHP Chinese website Q&A
Let’s take a look and learn.
(super(name,age))相当于原始寄生组合继承中的 Person.call(this,name,age)