关于javascript解决闭包漏洞的一个问题详解

var o = (()=>{
    var obj = {
        a:1,
        b:2,
    };
    return {
        get :(n)=>{
            return obj[n]
        }
    }
})()

console.log(o.get("a"));//1
console.log(o.get("b"));//2

console.log(o.get("valueOf"));
//[Function: valueOf]
let obj2 = o.get("valueOf")()
//TypeError: Cannot convert undefined or null to object

Object.defineProperty(Object.prototype,"abc",{
    get(){
        return this
    }
})
console.log(o.get("abc"));//{ a: 1, b: 2 }

let obj = o.get("abc")
obj.a='hjkasd'
obj.b='12345'
obj.c='勇敢牛牛，不怕困难'
console.log(obj);//{ a: 'hjkasd', b: '12345', c: '勇敢牛牛，不怕困难' }

var o = (()=>{
    var obj = {
        a:1,
        b:2,
    };
    return {
        get :(n)=>{
            if(!obj.hasOwnProperty(n)){
                return `${n}在此对象本身不存在`
            }
            return obj[n]
        }
    }
})()

var o = (()=>{
    let obj = {
        a:1,
        b:2,
    };
    Object.setPrototypeOf(obj,null)
    return {
        get :(n)=>{
            return obj[n]
        }
    }
})()