JavaScript 对象的遍历

1. 使用Object.keys();

var book = {
    "title": "JavaScript 教程",
    "author": "Mike"
}
var keys = Object.keys(book); //返回对象的所有可枚举属性

keys.forEach(function (key) {
    console.log(key + ":" + book[key]);
})

2. 使用for … in …

var book = {
    "title": "JavaScript 教程",
    "author": "Mike"
}
for (var i in book) {
    console.log(i + ":" + book[i]);
}

3.使用Object.getOwnPropertyNames();

var book = {
    "title": "JavaScript 教程",
    "author": "Mike"
}
//返回一个数组,包含对象自身的所有属性(不含Symbol属性,但是包括不可枚举属性).
var properts = Object.getOwnPropertyNames(book);
properts.forEach(function (propert) {
    console.log(propert + ":" + book[propert]);
});

4.使用Reflect.ownkeys();

 var book = {
 "title": "JavaScript 教程",
     "author": "Mike"
 }
 //返回一个数组,包含对象的所有属性,不管属性名是Symbol或字符串,也不管是否可枚举. 
 var keys = Reflect.ownKeys(book);
 keys.forEach(function (key) {
     console.log(key + ":" + book[key]);
 });

参考： 原文