• extends
    • super
    • 扩张或重写方法 ```javascript // 父类 class People {
      1.    constructor(name) {
      2.        this.name = name;
      }
      1. eat() {
      2.        console.log(`${this.name} eat something`)
      } }

    //子类 class Student extends People { constructor(name, number) { super(name) this.number = number; } sayHi() { console.log(姓名 ${this.name} 学号 ${this.number}) } }

    // 子类 class Teacher extends People { constructor(name, major) { super(name) this.major = major; } teach() { console.log(姓名 ${this.name} 课程 ${this.major}) } }

    const xialuo = new Student(‘夏洛’, 100); console.log(xialuo.name); console.log(xialuo.number); xialuo.sayHi(); xialuo.eat();

    const wang = new Teacher(‘王老师’, ‘语文’); console.log(wang.name); console.log(wang.major); wang.eat(); wang.teach(); ```