在JavaScript中展平JSON对象

function flattenJSON(json, parentKey = '') {
  let flattened = {};
  for (let key in json) {
    if (json.hasOwnProperty(key)) {
      let newPath = parentKey ? `${parentKey}.${key}` : key;
      if (typeof json[key] === 'object' && json[key] !== null) {
        Object.assign(flattened, flattenJSON(json[key], newPath));
      } else {
        flattened[newPath] = json[key];
      }
    }
  }
  return flattened;
}

// 示例用法
let json = {
  name: 'John',
  age: 30,
  address: {
    street: '123 Main St',
    city: 'New York',
    country: 'USA'
  }
};

let flattenedJSON = flattenJSON(json);
console.log(flattenedJSON);

{
  name: 'John',
  age: 30,
  'address.street': '123 Main St',
  'address.city': 'New York',
  'address.country': 'USA'
}