【23种设计模式】5原型模式

描述：用原型实例指定创建对象的种类，拷贝原型创建新对象
优点：简化创建新对象的过程，动态获取对象运行时，属性修改父变子变
缺点：修改已有类时，违反开闭原则

应用：创建成本较大的场景，需要动态获取当前对象运行状态的场景

---

classDiagram
  class Prototype{
    <>
    clone():Prototype
  }
  class Dog{
    +name: string
    +birthYear: number
    +sex: string
    +presentYear: number
    constructor()
    +getDiscription() string
    +clone() Prototype
  }
  Prototype <|-- Dog :实现

• 原型对象接口
  • 实例实现类
• 实例调用类中的方法

interface Prototype {
    clone():Prototype;
}
class Dog implements Prototype {
    public name: string;
    public birthYear: number;
    public sex: string;
    public presentYear: number;
    constructor() {
        this.name = "lili";
        this.birthYear = 2015;
        this.sex = "男";
        this.presentYear = 2018;
    }
    public getDiscription(): string {
        return `狗狗叫${this.name},性别${this.sex},${this.presentYear}年${this.presentYear - this.birthYear}岁了`
    }
    // 实现复制
    public clone(): Prototype {
        return Object.create(this);
    }
}
// 使用
const dog = new Dog();
console.log(dog.getDiscription());
// 拷贝不会影响原实例
const dog1 = Object.create(dog);
dog1.presentYear = 2020;
console.log(dog1.getDiscription());
const dog2 = dog.clone();
console.log('--');
console.log(dog.getDiscription());
console.log(dog1.getDiscription());
console.log(dog2.getDiscription());