es6/test12.html at master · Sstriving/es6 · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>属性的遍历</title>
</head>
<body>
<script>
//    1.for ... in obj 遍历
    var obj = {
        name:"zhangsan",
        sex:"nan",
        age:12,
        phone:15829309883,
        address:"陕西省西安市长安区"
    }
    for (x in obj){
        console.log(x);
    }
//    2.Object.keys(obj)遍历
    var key = Object.keys(obj);
    console.log(key)
//      3.Object.getOwnPropertyNames(obj)遍历
    var pro = Object.getOwnPropertyNames(obj);
    console.log(pro)
    var Symbols = Object.getOwnPropertySymbols(obj);
    console.log(Symbols);
    var reflect = Reflect.ownKeys(obj);
    console.log(reflect)
//      Object.values返回一个数组，为对象的键值
    var value = Object.values(obj)
    console.log(value);
//    Object.entries返回一个数组，为对象属性的键值对数组
    var entries = Object.entries(obj)
    console.log(entries)
    var a = {
        x:"1"
    };
    a?.b = 42;
    alert(a.b);
</script>
</body>
</html>