JSON.stringify() 的高级特征及进阶用法

const obj = { name: "谜语人", age: 25 };
console.log(JSON.stringify(obj)); 
// 输出: {"name":"谜语人","age":25}

const obj = {
  name: "谜语人",
  age: 25,
  password: "123456789",
  city: "广岛"
};
// 只序列化 'name' 和 'age' 属性
const result = JSON.stringify(obj, ["name", "age"]);
console.log(result); 
// 输出: {"name":"谜语人","age":25}

const obj = {
  name: "黑衣人",
  age: 28,
  password: "admin1111",
  lastLogin: new Date(),
  todos: [
    { id: 1, text: "啊啊啊啊啊啊", done: true },
    { id: 2, text: "踩踩踩踩踩踩踩踩踩踩踩踩", done: false }
  ]
};
function replacer(key, value) {
  // 过滤掉密码字段
  if (key === "password") return undefined;
  // 将 Date 对象转换为 ISO 字符串
  if (value instanceof Date) return value.toISOString();
  // 将布尔值转换为更友好的文本
  if (key === "done") {
    return value ? "Completed" : "Pending";
  }
  // 默认返回原值
  return value;
}
const result = JSON.stringify(obj, replacer, 2);
console.log(result);

// 使用数字指定缩进空格数
JSON.stringify(obj, null, 2);
// 使用字符串作为缩进符
JSON.stringify(obj, null, "----");

const obj = {
  name: "Alice",
  age: 25,
  sensitiveInfo: "This should not be logged entirely",
  toJSON: function() {
    return {
      name: this.name,
      age: this.age,
      generatedAt: new Date().toISOString(),
      // 只显示敏感信息的前10个字符
      sensitiveInfo: this.sensitiveInfo.substring(0, 10) + "..."
    };
  }
};
console.log(JSON.stringify(obj));
// 输出: {"name":"Alice","age":25,"generatedAt":"2025-09-02T08:25:42.000Z","sensitiveInfo":"This shoul..."}