[JS]对象遍历顺序&几种方法的区别

const obj = {
  2: 2,
  name: "Frenkie",
  age: 25,
  0: 0,
  [Symbol("hello")]: "hello",
  102: 102,
  26: 26,
  1.1："1.1"
};

obj.__proto__.原型属性 = "hello";
const for_in_arr = [];
for (const key in obj) {
  for_in_arr.push(key);
}
//列出自身和原型中的所有可枚举属性，不包含Symbol
console.log("for_in_arr", for_in_arr);//["0","2","26","102","name","age","1.1","原型属性"]
//列出自身可枚举属性，不包含Symbol
console.log("Object.keys()", Object.keys(obj));//["0","2","26","102","name","age","1.1"]
//列出自身全部可枚举属性
console.log("Rflect", Reflect.ownKeys(obj));//["0","2","26","102","name","age","1.1",Symbol("hello")]

1. 首先列出类数组索引（非负数）的所有属性，按数值大小升序排列；
2. 然后依次列出剩下的字符串名字（包含所有负数和浮点数）；
3. 最后列出属性名为符号对象类型（Symbol()）的属性.