面向对象 多态

class People {
    constructor(name) {
        this.name = name
    }
    saySomething() {

    }
}

class A extends People {
    constructor(name) {
        super(name)
    }
    saySomething() {
        alert(‘I am A‘)
    }
}

class B extends People {
    constructor(name) {
        super(name)
    }
    saySomething(){
        alert(‘I am B‘)
    }
}

let a = new A(‘a‘);
a.saySomething();
let b = new B(‘b‘);
b.saySomething();