如何通过 id 组合多个对象 [重复]

Question

我有一个数据集，它对两个不同的对象使用相同的 _id，并在整个文件中重复此操作。如何浏览对象列表，找到具有匹配 _id 的两个对象并将它们合并为一个对象？

[    
   {
      "_id": "591323037ca83d48eac1ff31",
      "sessionStartTime": "2017-05-09T23:10:40.000Z",
      "sessionEndTime": "2017-05-10T07:28:40.000Z",
      "timeSessionMinutes": 212,
    },
    {
      "_id": "591323037ca83d48eac1ff31",
      "eventSummary": "Working",
      "eventActivity": "Work",
      "eventStart": "2017-05-09T10:00:00+02:00",
      "eventEnd": "2017-05-09T17:00:00+02:00"
    },
    {
      "_id": "5917165b3ffac25462193490",
      "sessionStartTime": "2017-05-12T22:06:09.000Z",
      "sessionEndTime": "2017-05-13T06:12:09.000Z",
      "timeSessionMinutes": 322,
    },
    {
      "_id": "5917165b3ffac25462193490",
      "eventSummary": "Traveling back home",
      "eventActivity": "Travel",
      "eventStart": "2017-05-09T17:00:00+02:00",
      "eventEnd": "2017-05-09T17:30:00+02:00"
    },
    ...
]

很抱歉，如果已经回答，找不到此特定用例的解决方案。

Answer 1

另一种方法是使用函数reduce 按_id 对对象进行分组，并使用函数Object.values 提取分组的对象。

let arr = [   {      "_id": "591323037ca83d48eac1ff31",      "sessionStartTime": "2017-05-09T23:10:40.000Z",      "sessionEndTime": "2017-05-10T07:28:40.000Z",      "timeSessionMinutes": 212,    },    {      "_id": "591323037ca83d48eac1ff31",      "eventSummary": "Working",      "eventActivity": "Work",      "eventStart": "2017-05-09T10:00:00+02:00",      "eventEnd": "2017-05-09T17:00:00+02:00"    },    {      "_id": "5917165b3ffac25462193490",      "sessionStartTime": "2017-05-12T22:06:09.000Z",      "sessionEndTime": "2017-05-13T06:12:09.000Z",      "timeSessionMinutes": 322,    },    {      "_id": "5917165b3ffac25462193490",      "eventSummary": "Traveling back home",      "eventActivity": "Travel",      "eventStart": "2017-05-09T17:00:00+02:00",      "eventEnd": "2017-05-09T17:30:00+02:00"    }],
    result = Object.values(arr.reduce((a, c) => {
      Object.assign((a[c['_id']] || (a[c['_id']] = Object.create(null))), c);
      return a;
    }, Object.create(null)));

console.log(result);

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