类

class Animal{
    public name;
    public constructor(name){
        this.name = name;
    }
}

        let a = new Animal('lx');
        cc.log(a.name);     //如果用private修饰就不能访问
        a.name = 'hello';
        cc.log(a.name)

class Animal{
    protected name;
    public constructor(name){
        this.name = name;
    }
}

class Cat extends Animal{
    constructor(name){
        super(name);
        this.name = 'xx'; //private修饰的子类也不能访问，protected修饰的可以
    }
}

当构造函数修饰为 private 时，该类不允许被继承或者实例化

当构造函数修饰为 protected 时，该类只允许被继承

class Animal{
    public readonly name;
    public constructor(name){
        this.name = name;
    }
}

　　let temAnimal = new Animal('aaa');

　　temAnimal.name = 'ddd'; //只读属性不能赋值

//抽象类是不允许被实例化
//抽象类中的抽象方法必须被子类实现
abstract class Animal {
    public name;
    public constructor(name) {
        this.name = name;
    }
    public abstract sayHello();
}

class Cat extends Animal {
    constructor(name) {
        super(name);
    }
    public sayHello()
    {

    }
}

let a: Cat = new Cat('msk');    //类的类型