javascript - 从具有相同键的对象创建一个新数组

Question

我有一个对象数组。我想将对象合并到一个数组中，并使用其中一个值作为键。在下面的示例中，我有一个数据数组，我从服务器获取该数据数组作为对 API 的响应，并且我想使用 call_id 作为将响应索引到新数组的键。

我尝试过:
data.map(function(index, elem) {responses[index.call_id] = index;})
但这显然只能获取最后一个数组，并且添加 [] 会给我一个错误

当前数组:

[
    {
        "id": 2,
        "survey_id": 1,
        "question_id": 2,
        "response": 1,
        "order_id": null,
        "customer_id": 1,
        "call_id": 108,
        "created_at": "2020-02-20 18:18:47",
        "updated_at": "2020-02-20 18:18:47",
        "question": "Do you want it gift wrapped?",
        "first_name": "Zain",
        "sid": "CA1564cda12b7e1364dc967538c7bdf617"
    },
    {
        "id": 1,
        "survey_id": 1,
        "question_id": 1,
        "response": 2,
        "order_id": null,
        "customer_id": 1,
        "call_id": 108,
        "created_at": "2020-02-20 18:18:32",
        "updated_at": "2020-02-20 18:18:32",
        "question": "Is your order confirmed?",
        "first_name": "Zain",
        "sid": "CA1564cda12b7e1364dc967538c7bdf617"
    },
    {
        "id": 1,
        "survey_id": 1,
        "question_id": 1,
        "response": 2,
        "order_id": null,
        "customer_id": 1,
        "call_id": 109,
        "created_at": "2020-02-20 18:18:32",
        "updated_at": "2020-02-20 18:18:32",
        "question": "Is your order confirmed?",
        "first_name": "Zain",
        "sid": "CA1564cda12b7e1364dc967538c7bdf617"
    }
]

预期结果

[{
    '108': [
        {
            "id": 2,
            "survey_id": 1,
            "question_id": 2,
            "response": 1,
            "order_id": null,
            "customer_id": 1,
            "call_id": 108,
            "created_at": "2020-02-20 18:18:47",
            "updated_at": "2020-02-20 18:18:47",
            "question": "Do you want it gift wrapped?",
            "first_name": "Zain",
            "sid": "CA1564cda12b7e1364dc967538c7bdf617"
        },
        {
            "id": 1,
            "survey_id": 1,
            "question_id": 1,
            "response": 2,
            "order_id": null,
            "customer_id": 1,
            "call_id": 108,
            "created_at": "2020-02-20 18:18:32",
            "updated_at": "2020-02-20 18:18:32",
            "question": "Is your order confirmed?",
            "first_name": "Zain",
            "sid": "CA1564cda12b7e1364dc967538c7bdf617"
        }
    ], 
    '109' : [
        {
            "id": 1,
            "survey_id": 1,
            "question_id": 1,
            "response": 2,
            "order_id": null,
            "customer_id": 1,
            "call_id": 109,
            "created_at": "2020-02-20 18:18:32",
            "updated_at": "2020-02-20 18:18:32",
            "question": "Is your order confirmed?",
            "first_name": "Zain",
            "sid": "CA1564cda12b7e1364dc967538c7bdf617"
        }
    ]  
}]

Answer 1

我认为您想要如下所示的内容，对吗？

如果是的话，让我解释一下:
您将使用 .reduce()，它使用两个值作为参数，一个累加器(在本例中是一个对象)和正在迭代的当前值(在本例中是数组中的每个对象)

每次迭代都会检查累加器，看看当前迭代对象的call_id是否已经存在，如果存在，则将对象插入其中，如果不存在，则创建一个新对象以 call_id 作为键。

注意:我使用属性较少的数组只是为了更好地可视化代码

let arr = [{
    "id": 2,
    "call_id": 108,
    "sid": "CA1564cda12b7e1364dc967538c7bdf617"
  },
  {
    "id": 1,
    "call_id": 108,
    "sid": "CA1564cda12b7e1364dc967538c7bdf617"
  },
  {
    "id": 3,
    "call_id": 109,
    "sid": "CA1564cda12b7e1364dc967538c7bdf617"
  }
]


let result = arr.reduce(function(accObj, currentObj) {
  accObj[currentObj.call_id] = accObj[currentObj.call_id] || [];
  accObj[currentObj.call_id].push(currentObj);
  return accObj;
}, {}); //{} is the accumulator object

console.log(result);