映射/组织节点中的嵌套对象

Question

我正在尝试自己映射嵌套对象，而不使用 JoinJS 之类的东西，这在一定程度上效果很好，直到我想正确地让我的 JSON 看起来很漂亮。

基于 SQL 查询，我的输出是：

[
  {
    "id": 1,
    "city_name": "city 1 - some city name",
    "city_category": "city 1 - some category",
    "city_description": "city 1 - some city description",
    "city_id": 1,
    "store_id": 1
  },
  {
    "id": 1,
    "city_name": "city 1 - some city name",
    "city_category": "city 1 - some category",
    "city_description": "city 1 - some city description",
    "city_id": 1,
    "store_id": 2
  },
  {
    "id": 1,
    "city_name": "city 1 - some city name",
    "city_category": "city 1 - some category",
    "city_description": "city 1 - some city description",
    "city_id": 1,
    "store_id": 3
  },
  {
    "id": 2,
    "city_name": "city 2 - some city name",
    "city_category": "city 2 - some category",
    "city_description": "city 2 - some city description",
    "city_id": 2,
    "store_id": 1
  },
  {
    "id": 2,
    "city_name": "city 2 - some city name",
    "city_category": "city 2 - some category",
    "city_description": "city 2 - some city description",
    "city_id": 2,
    "store_id": 2
  }
]

我试图让这个输出看起来像这样：

[
  {
    "city_id": 1,
    "city_name": "city 1 - some city name",
    "city_category": "city 1 - some category",
    "city_description": "city 1 - some city description",
    "store_ids": [1,2,3]
  }
  {
    "city_id": 2,
    "city_name": "city 2 - some city name",
    "city_category": "city 2 - some category",
    "city_description": "city 2 - some city description",
    "store_ids": [1,2]
  }
]

我的第一个猜测是我需要使用_.chain(result).uniqBy('city_id').value() 找到所有唯一的id 或city_id。但后来我有点坚持从输出中删除id，最重要的是，如何创建一个新键store_ids，它具有每个城市所有商店的数组。有意义吗？

使用Lodash 或者只是简单的 JS（没有像 JoinJS 这样的其他模块，除非它们对这样的事情很有效），我将如何操作它？？

Answer 1

我会遍历结果，并将它们分组到我的新对象结果中。 最后你会有一个对象的对象，键是item.id， 但是如果你想把它转换成数组很简单。

let resultsObject = {};

sqlQueryRows.map(function(item) {
   if (item.id in resultsObject) {
       resultsObject[item.id].store_ids.push(item.store_id);
   } else {
       resultsObject[item.id] = {
           city_id: item.city_id,
           city_name: item.city_name,
           city_category: item.city_category,
           city_description: item.city_description,
           store_ids: [item.store_id] 
       }
   }
});

// if you need an array
let resultsArray = Object.values(resultsObject);

Answer 2

这是我的 lodash 方法：

_(data)
  .uniqBy('city_id')
  .map(_.partialRight(_.omit, 'store_id'))
  .map(i => _.defaults({
    store_ids: _(data)
      .filter({ city_id: i.city_id })
      .map('store_id')
      .value()
  }, i))
  .value();

这个想法是：

• 获取独特的城市。
• 删除存储 ID。
• 通过按唯一城市 ID 过滤原始数据来创建存储 IDs 数组。

Answer 3

如果您只是想删除某些字段，您可以使用 .map 方法，但我不确定我是否完全理解这个问题。

var new_array = array_name.map((val) => {
    //do stuff to array
}