js json object

let jsonObject = {
    "name": "John Doe",
    "age": 30,
    "isStudent": false,
    "courses": ["Math", "English"],
    "address": {
        "street": "123 Main St",
        "city": "Anytown"
    }
};

console.log(jsonObject.name); // 输出: John Doe
console.log(jsonObject.courses[0]); // 输出: Math
console.log(jsonObject.address.city); // 输出: Anytown

let jsonString = JSON.stringify(jsonObject);
console.log(jsonString);
// 输出: {"name":"John Doe","age":30,"isStudent":false,"courses":["Math","English"],"address":{"street":"123 Main St","city":"Anytown"}}

let parsedObject = JSON.parse(jsonString);
console.log(parsedObject.name); // 输出: John Doe

try {
    let invalidJsonString = '{ "name": "John", }'; // 错误的JSON字符串
    let obj = JSON.parse(invalidJsonString);
} catch (error) {
    console.error("Invalid JSON string:", error);
}

let a = {};
let b = {a: a};
a.b = b; // 创建循环引用

// 这将导致错误
try {
    JSON.stringify(a);
} catch (error) {
    console.error("Circular reference detected:", error);
}

// 解决方法：断开循环引用
a.b = undefined;
let jsonString = JSON.stringify(a); // 现在可以正常工作