SOURCE

//懒汉式
// let ShopCar = (function(){
//     let instance
//     function init(){
//         //这里定义单例代码
//         goods:[] //购物的物品,
//         return {
//             buy(good){
//                 this.goods.push(good)
//             }
          
//         }
//     }

//     return {
//         getInstance:function(){
//             if(!instance){
//                 instance = init()
//             }
//             return instance
//         }
//     }
// })()
// let car1 = ShopCar.getInstance()
// let car2 = ShopCar.getInstance()
// car1.buy('橘子')
// car2.buy('苹果')
// console.log(car1.goods)
// console.log(car1==car2)

//饿汉式
var ShopCar = (function(){
    var instance = init()
    function init(){
        return {
        goods:[],
        buy(good){
      this.goods.push(good)
        }
        }
    
    }
    return {
        getInstance:function(){
            return instance
        }
    }
})()
let car1 = ShopCar.getInstance()
let car2 = ShopCar.getInstance()
car1.buy('橘子')
car2.buy('苹果')
console.log(car1.goods)
console.log(car1==car2)