js获取字段可以吗

const person = {
  name: "Alice",
  age: 25
};

// 获取'name'字段
console.log(person.name); // 输出: Alice

// 获取'age'字段
console.log(person.age); // 输出: 25

const person = {
  "first name": "Bob", // 属性名包含空格
  age: 30
};

// 使用变量获取字段
const fieldName = "age";
console.log(person[fieldName]); // 输出: 30

// 获取包含特殊字符的字段
console.log(person["first name"]); // 输出: Bob

const person = {
  name: "Charlie",
  age: 28,
  city: "New York"
};

// 获取所有键
const keys = Object.keys(person);
console.log(keys); // 输出: ["name", "age", "city"]

// 获取所有值
const values = Object.values(person);
console.log(values); // 输出: ["Charlie", 28, "New York"]

const person = {
  name: "Diana",
  age: 22
};

for (let key in person) {
  if (person.hasOwnProperty(key)) { // 排除继承属性
    console.log(`${key}: ${person[key]}`);
  }
}
// 输出:
// name: Diana
// age: 22

const person = { name: "Eve" };

if (person.age !== undefined) {
  console.log(person.age);
} else {
  console.log("Age is not defined.");
}
// 输出: Age is not defined.

const obj = {
  "user name": "Frank"
};

console.log(obj["user name"]); // 正确
// console.log(obj.user name); // 语法错误

const key = "country";
const data = { country: "Germany" };

console.log(data[key]); // 输出: Germany