JavaScript中JSON的过滤级别递归地保留子对象

function filterJSON(json, filter) {
  if (typeof json !== 'object') {
    return json;
  }

  if (Array.isArray(json)) {
    return json.map(item => filterJSON(item, filter));
  }

  const result = {};
  for (let key in json) {
    if (json.hasOwnProperty(key)) {
      const value = json[key];
      if (filter(key, value)) {
        result[key] = filterJSON(value, filter);
      }
    }
  }

  return result;
}

const json = {
  "name": "John",
  "age": 30,
  "address": {
    "street": "123 Main St",
    "city": "New York",
    "country": "USA"
  }
};

const filteredJSON = filterJSON(json, (key, value) => {
  // 保留所有子对象
  return typeof value === 'object';
});

console.log(filteredJSON);

{
  "address": {
    "street": "123 Main St",
    "city": "New York",
    "country": "USA"
  }
}