属性的封装

class Animal {
    private _name: string;
    private _age: number;
   
    constructor(name: string,age: number){
        this._name = name;
        this._age = age;
    }

    sayHello(){
        console.log("hello");
    }

    get name(){
        return this._name;
    }
    set name(name){
        this._name = name;
    }

    get age(){
        return this._age;
    }
    set age(age){
        this._age = age;
    }
}

const an = new Animal("小黑",3);
an.name = "小红"
console.log(an);