一个类返回一个实例，再次创建时调用直接返回
class CreateUser{
constructor(name){
this.name = name;
this.getName();
}
getName(){
return this.name;
}
}
const ProxyModel = ( () =>{
let instance = null;
return (name) => {
if(!instance){
instance = new CreateUser(name);
}
return instance;
}
} )();
let p1 = new ProxyModel("vn");
let p2 = new ProxyModel("ln");
console.info(p1,p2);
策略类只关注算法的实现，定义统一的接口来调用这些方法
const levelData = {
"a" : money => money * 4,
"b" : money => money * 3,
"c" : money => money * 2
}
const getMoney = (level,money) => levelData[level](money);
console.info(getMoney("a",200));