2.13Ts静态属性，setter和getter

class Person5 {
  constructor(private name: string) {}
  get getName() {
    return this.name;
  }
}
const person5 = new Person5("dell5");
console.log(person5.getName);

// 单例模式
class Demo {
  private static instance: Demo;
  private constructor(public name: string) {}
  static getInstance() {
    if (!this.instance) {
      this.instance = new Demo("dell lee");
    }
    return this.instance;
  } //把这个方法直接挂在类上，而不是类的实例上
}
const demo1 = Demo.getInstance();
const demo2 = Demo.getInstance(); // 构建了单例
// demo1 == demo2 // true
console.log(demo1.name);
console.log(demo2.name);