如何迭代JavaScript对象的属性？

可以，JavaScript 中有多种遍历对象属性的方法。1. 使用 for...in 循环可遍历对象的所有可枚举字符串属性，但建议配合 hasOwnProperty() 排除继承属性；2. 使用 Object.keys() 结合 forEach() 可更方便地以数组方式处理键名；3. 使用 Object.entries() 可直接获取键值对数组，便于解构和操作；此外还可根据需要在循环内添加逻辑实现属性过滤等功能。

Yes, you can absolutely loop through the properties of a JavaScript object — and there are a few common ways to do it depending on what exactly you need.

1. Using for...in Loop

This is the most straightforward method for iterating over object properties.

The for...in loop goes through each enumerable string property of an object. Here's how you'd use it:

const user = {
  name: "Alice",
  age: 25,
  role: "Developer"
};

for (let key in user) {
  console.log(key   ": "   user[key]);
}

You’ll get:

name: Alice
age: 25
role: Developer

⚠️ A quick note: make sure to use hasOwnProperty() if you want to skip inherited properties:

for (let key in user) {
  if (user.hasOwnProperty(key)) {
    console.log(key   ": "   user[key]);
  }
}

2. Using Object.keys() with forEach()

If you just want the keys as an array and then perform an action on them, this is a clean approach.

Object.keys(user).forEach(key => {
  console.log(key   ": "   user[key]);
});

This gives you the same result but may feel more functional or array-like, especially if you're used to working with array methods like map, filter, etc.

3. Using Object.entries() for Key-Value Pairs

If you need both keys and values without accessing the object each time, Object.entries() is super handy.

It returns an array of [key, value] pairs:

Object.entries(user).forEach(([key, value]) => {
  console.log(`${key}: ${value}`);
});

This makes destructuring easy and keeps your code clean when dealing with both parts of a property.

Bonus Tip: Filtering Object Properties

Sometimes you might only want certain properties. Let’s say you only want string values:

Object.entries(user).forEach(([key, value]) => {
  if (typeof value === 'string') {
    console.log(`${key}: ${value}`);
  }
});

This lets you add logic inside the loop easily.

So yeah, looping through object properties isn’t hard once you know which method fits your case.
基本上就这些。

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