js中es6语法Symbol

<script>
    let s=Symbol()
    console.log(typeof s);
    let s1=Symbol("贾维斯")
    //description可以获取symbol描述
    console.log(s1.description);
    //读取Symbol值Object.getOwnPropertySymbols
    let info3Symbol=Symbol("job")
    let info3={
       name:"贾维斯",
       age:20,
       [info3Symbol]:"星期五"
    }
    for(let key in info3){
       console.log(key);
    }
    console.log(Object.getOwnPropertySymbols(info3));
    //需要创建重复的Symbol值，需要使用Symbol.for
    let  itsybol=Symbol.for("贾维斯")
    let  itsybol1=Symbol.for("贾维斯")
    console.log(itsybol===itsybol1);
</script>