js把对象转成string

const obj = { a: 1 };
console.log(obj.toString()); // 输出: [object Object]

const obj = { a: 1, b: { c: 2 } };
const jsonString = JSON.stringify(obj);
console.log(jsonString); // 输出: {"a":1,"b":{"c":2}}

// 格式化输出
const formattedJson = JSON.stringify(obj, null, 2);
console.log(formattedJson);
/* 输出:
{
  "a": 1,
  "b": {
    "c": 2
  }
}
*/

const obj = {
  a: 1,
  b: 2,
  toString: function() {
    return `a: ${this.a}, b: ${this.b}`;
  }
};
console.log(obj.toString()); // 输出: a: 1, b: 2

const obj = { a: 1, b: function() {}, [Symbol('c')]: 3 };
const jsonString = JSON.stringify(obj, (key, value) => {
  if (typeof value === 'function' || typeof value === 'symbol') {
    return undefined; // 这将排除这些属性
  }
  return value;
});
console.log(jsonString); // 输出: {"a":1}

const obj = { a: 1 };
obj.b = obj; // 循环引用

try {
  console.log(JSON.stringify(obj));
} catch (e) {
  console.error(e); // TypeError: Converting circular structure to JSON
}

// 使用 flatted 库
const { stringify } = require('flatted');
console.log(stringify(obj)); // 输出: {"a":1,"b":"~"}