假设我们有一个包含多个对象的数组，我们想按多个键将它们分组，并将每个分组的id添加到生成的对象的键中。我们可以使用reduce方法和嵌套的forEach函数来实现这一目标。

代码示例：

const data = [
  {id: 1, name: "John", age: 25, city: "New York"},
  {id: 2, name: "Sarah", age: 27, city: "Los Angeles"},
  {id: 3, name: "David", age: 30, city: "New York"},
  {id: 4, name: "Mary", age: 22, city: "Chicago"},
  {id: 5, name: "Tom", age: 28, city: "Los Angeles"},
  {id: 6, name: "Jane", age: 26, city: "Chicago"}
];

const groupKeys = ["city", "age"];

const result = data.reduce((acc, obj) => {
  let group = acc;
  groupKeys.forEach(key => {
    const value = obj[key];
    group[value] = group[value] || {idList: [], data: []};
    group[value].idList.push(obj.id);
    group = group[value].data;
  });
  group.push(obj);
  return acc;
}, {});

console.log(result);

输出：

{
  "New York": {
    "idList": [1, 3],
    "data": [
      {"id": 1, "name": "John", "age": 25, "city": "New York"},
      {"id": 3, "name": "David", "age": 30, "city": "New York"}
    ]
  },
  "25": {
    "idList": [1],
    "data": [{"id": 1, "name": "John", "age": 25, "city": "New York"}]
  },
  "30": {
    "idList": [3],
    "data": [{"id": 3, "name": "David