js 关联数组转字符串

以下是两种将JS关联数组转换为字符串的方法：
1. 使用for循环和字符串拼接的方式：

let arr = {name: "John", age: 30, city: "New York"};
let str = "";
for (let key in arr) {
  str += key + ":" + arr[key] + ",";
}
str = str.substring(0, str.length - 1); // 去掉最后一个逗号
console.log(str); // 输出：name:John,age:30,city:New York

2. 使用toString()方法：

let arr = {name: "John", age: 30, city: "New York"};
console.log(Object.entries(arr).toString()); // 输出：name,John,age,30,city,New York