将嵌套对象的数组转换为平面对象

function flattenArray(arr) {
  const result = {};

  function flatten(obj, prefix = '') {
    for (let key in obj) {
      if (typeof obj[key] === 'object' && !Array.isArray(obj[key])) {
        flatten(obj[key], prefix + key + '.');
      } else {
        result[prefix + key] = obj[key];
      }
    }
  }

  arr.forEach((obj, index) => {
    flatten(obj, index + '.');
  });

  return result;
}

const nestedArray = [
  {
    id: 1,
    name: 'John',
    address: {
      street: '123 Main St',
      city: 'New York',
      country: 'USA'
    }
  },
  {
    id: 2,
    name: 'Jane',
    address: {
      street: '456 Elm St',
      city: 'Los Angeles',
      country: 'USA'
    }
  }
];

const flattenedObject = flattenArray(nestedArray);
console.log(flattenedObject);

{
  '0.id': 1,
  '0.name': 'John',
  '0.address.street': '123 Main St',
  '0.address.city': 'New York',
  '0.address.country': 'USA',
  '1.id': 2,
  '1.name': 'Jane',
  '1.address.street': '456 Elm St',
  '1.address.city': 'Los Angeles',
  '1.address.country': 'USA'
}