js 取json key

let jsonObj = {
  "name": "张三",
  "age": 30,
  "city": "北京"
};

let name = jsonObj.name; // "张三"
let age = jsonObj.age; // 30
let city = jsonObj.city; // "北京"

let key = "name";
let name = jsonObj[key]; // "张三"

let cityKey = "city";
let city = jsonObj[cityKey]; // "北京"

// JSON对象
let person = {
  "firstName": "李雷",
  "lastName": "韩梅梅",
  "age": 28,
  "isStudent": false
};

// 使用点符号获取值
console.log(person.firstName); // 输出: 李雷

// 使用方括号获取值
let key = "lastName";
console.log(person[key]); // 输出: 韩梅梅

// 遍历对象的所有key
for (let key in person) {
  if (person.hasOwnProperty(key)) {
    console.log(key + ": " + person[key]);
  }
}