手写实现深度拷贝

function deepCopy(obj) {
  // 判断是否为基本数据类型
  if (typeof obj !== 'object' || obj === null) {
    return obj;
  }
  
  // 创建新的对象或数组
  const copy = Array.isArray(obj) ? [] : {};
  
  // 递归拷贝属性
  for (let key in obj) {
    if (obj.hasOwnProperty(key)) {
      copy[key] = deepCopy(obj[key]);
    }
  }
  
  return copy;
}

const obj = {
  name: 'John',
  age: 30,
  address: {
    city: 'New York',
    country: 'USA'
  }
};

const copy = deepCopy(obj);

console.log(copy);
// 输出: { name: 'John', age: 30, address: { city: 'New York', country: 'USA' } }

console.log(copy === obj);
// 输出: false

console.log(copy.address === obj.address);
// 输出: false