es6/test13.html at master · Sstriving/es6 · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
//    Symbol数据类型，表示独一无二的值
//    var obj = {
//        [a]:Symbol("xx"),
//        [b]:Symbol("YY")
//    }
    var  s = Symbol("foo");
    var  ss = Symbol("fool");
    console.log(s);
    console.log(ss);
    var a = {
        [s]:"hello"
    }
    console.log(a[s]);
    var obj = {
        name:"zhangan",
        sex:"man"
    };
    obj[s] = "hello";
    obj[ss] = "world";
//    获取对象的所有symbol属性名
    var objectSymbol = Object.getOwnPropertySymbols(obj);
    console.log(objectSymbol)
//    for(var i in obj){
//        console.log(i)
//    }
    console.log(Object.getOwnPropertyNames(obj))

//    Reflect.ownKeys(obj)可以返回所有类型的键名，包括常规键名和 Symbol 键名。

    var ownKeys = Reflect.ownKeys(obj);
    console.log(ownKeys);

//    Symbol.for("")方法
    var s1 = Symbol.for("test");
    var s2 = Symbol.for("test");
    console.log(s2);
    if (s2 === s1){
        alert(1)
    }
    var num = null;
    var ary = [1,2,3,4]
//    alert( num instanceof null);
//    alert(ary.constructor==Array)
//    var str = new String("1");
    var str = "!"
    function  test() {

    }
//    instanceof 判断引用类型对象是什么类型的
//    基本类型判断始终返回false
    alert(test instanceof Function);//true

</script>
</body>
</html>