TS-class类+类的继承+修饰符

 //类型别名 type
    type n = number;
    function f1(x:n):n{
        return x;
    }
    var n2:n =10;

    //联合类型别名
    type a = string | number[];
    var c1:a = 'ccc';
    var c2:a = [1,2,3];
    var c3:a = 11; //err c3的类型里面没有number类型

    //类 class 
    //首字母大写
    //类(class):定义了一件事物的抽象特点，包含它的属性和方法
    class A { //定义类，名称为A

    }
    //ES5
    function Person (name,age){
        this.name = name;
        this.age = age;
    }
    Person.prototype.say = function(){
        return this.name;
    }
    var p1 = new Person('cc',10);
    p1.name; //cc
    p1.say();
    //ES6
    //一个类必须有constructor
    //class ===> A {} === class A {constructor(){}}
    class Person2 {
        name:string; //提前定义值类型
        age:number;
        constructor(name,age){
            this.name = name;
            this.age = age;
        }
        say(){
            return this.name;
        }
    }
    var p2 = new Person2('bb',12);

    //类的继承
    //动物类
    class Animal {
        name:string;
        constructor(name){
            this.name = name;
        }
        eat(){
            return '吃肉'
        }
    }
    //继承
    class Cat extends Animal{
        constructor(name){
            super(name);
        }
        say(){
            return this.name+' '+ this.eat()  //调用父类的属性和方法
        }
    }
    var c = new Cat('vvv');
    c.say()
    
    //static 静态方法 修饰符 不需要实例化 可以直接通过类来调用
    class Animal2 {
        static url:string = "acc";
        static eat(){ //添加修饰符
            return '吃肉'
        }
        eat2 (){
            return '吃素'
        }
    }
    var a1 = new Animal2 ();
    // a1.eat() //err
    Animal2.eat(); //不需要实例化
    Animal2.url;
    // Animal2.eat2(); //err
    
    //修饰符
    //public 修饰的属性或方法是共有的，可以在任何地方被访问到，默认所有属性和方法都是public的
    //private 修饰的属性或方法是私有的，不能在声明它的类的外部访问
    //protected 修饰的属性或方法是收到保护的，它和private类似，区别是它在子类中也是允许被访问的
    class A2 {
        name:string;
        constructor(name){
            this.name = name
        }
        public static url:string = 'ccc';
        public eat(){
            return 'eat meat'
        }
        eat2(){
            return 'abstain from eating meat'
        }
    }
    //private 修饰的属性或方法是私有的，不能在声明它的类的外部访问
    class A3 {
        private eat(){
            return 'eat meat'
        }
        public eat2(){
            return 'adstain from eating meat'
        }
    }

    var a3 = new A3();
    a3.eat2();//正常访问
    a3.eat();//err 访问错误，但不影响正常编译

    //protected 修饰的属性是受到保护的，它和private类似，区别是它在子类中允许被访问
    class A4 {
        protected eat(){
            return 'eat meat'
        }
        private eat2(){
            return 'abstain from eating meat'
        }
        public eat3(){
            return 'polyphagia'
        }
    }
    class A5 extends A4 {
        constructor(){
            super()
        }
        fun(){
            return this.eat();//子类的内部是可以访问的
        }
        fun2(){
            return this.eat2(); //子类也不能访问
        }
    }
    var a4 = new A4();
    a4.eat();//err
    a4.eat2();//err
    a4.eat3()

    //类的类型
    class A6 {
        name:string;
        constructor(name){
            this.name = name;
        }
        eat():string{
            return 'eat meat'
        }
        eat2(n:string):number{
            return 1
        }
    }

    //类的接口实现
    //接口
    interface Obj{
        name:string,
        age?:number,
        say():string
    }
    //类的接口实现 implements--实现
    class A7 implements Obj{
        name:string;
        age:number;
        // age:number[]; //err age是可选属性 数据类型也受到接口的约束
        // name:number; //err name的类型受到接口的约束
        constructor(name){
            this.name = name;
        }
        say(){
            return '1'
        }
        say2(){
            return 1
        }
    }
    //demo
    //定义门 公共类
    class Door {

    }
    //定义防火门 ,门的子类
    class FireDoor extends Door implements Alertor {
        sound(){

        }
    }
    // 报警功能 接口
    interface Alertor {
        sound();
    }
    //灯 接口
    interface Light {
        lightOn();
        lightOff();
    }
    //车 类
    class Car implements Alertor,Light {
        sound(){

        }
        lightOn(){

        }
        lightOff(){

        }
    }
    //车类受到Alertor和Light接口的约束，所以sound(),lightOn(),lightOff()这三个方法必须得有