SOURCE

let CreatePeople = (function(){
    let instance = null
    return class {
        constructor(name,age){
            if(instance) return instance
            this.name = name
            this.age = age
            return instance = this
        }
    }
})()

let p1 = new CreatePeople("小明",18)
let p2 = new CreatePeople("小花",16)
console.log(p1)
console.log(p2)
console.log(p1===p2)


// 封装
let getSingleClass = function(customClass) {
    let instance = null
    return class {
        constructor(){
            if(instance) return instance
            instance = new customClass(...arguments);
            return instance
        }
    }
}

//使用
class CreateGirlFriend {
    constructor(name,age){
        this.name = name
        this.age = age
    }

}
let CreateSingleGirl = getSingleClass(CreateGirlFriend);
let g1 = new CreateSingleGirl("小红",17)
let g2 = new CreateSingleGirl("小率",18)
console.log(g1)
console.log(g2)
console.log(g1 === g2)