使用lodash等效的Mongodb $ unwind

如何解决使用lodash等效的Mongodb $ unwind

我有以下对象：

data =[
  {
    "id": "AQ103_2020-09-03T06:00:00.000Z","date": "2020-09-03T06:00:00.000Z","station": {
      "name": "AQ103","loc": {
        "type": "Point","coordinates": [
          45,12.45
        ]
      }
    },"samples": [
      {
        "t": "2020-09-03T06:10:57.617Z","data": {
          "PM1": 100,"PM10": 800,"O3": 300
        }
      },{
        "t": "2020-09-03T06:12:00.000Z","O3": 300.25,"NO2": 100.45
        }
      }
    ]
  },{
    "id": "AQ103_2020-09-03T10:00:00.000Z","date": "2020-09-03T07:00:00.000Z","samples": [
      {
        "t": "2020-09-03T07:10:57.617Z","PM10": 800
        }
      }
    ]
  },{
    "id": "AQ103_2020-09-03T09:00:00.000Z","date": "2020-09-03T09:00:00.000Z","samples": [
      {
        "t": "2020-09-03T09:46:55.256Z","data": {
          "PM1": 689.325,"CO": 47.849
        }
      },{
        "t": "2020-09-03T09:52:22.233Z","data": {
          "PM1": 200,"PM10": 200
        }
      }
    ]
  },"station": {
      "name": "AQ101","samples": [
      {
        "t": "2020-09-03T09:55:32.124Z","PM10": 800
        }
      }
    ]
  }
]

我想实现在MongoDB中使用$ unwind进行实现，而在javascript中使用 lodash 进行实现。 到目前为止，我能够使用flatMap整理数据为：

const output = _(data).flatMap('samples').value()
console.log(output)

但是我输了根本的电台名称！ 我的代码的输出是：

[
  {
    t: '2020-09-03T06:10:57.617Z',data: { PM1: 100,PM10: 800,O3: 300 }
  },{
    t: '2020-09-03T06:12:00.000Z',O3: 300.25,NO2: 100.45 }
  },{ t: '2020-09-03T07:10:57.617Z',PM10: 800 } },{ t: '2020-09-03T09:46:55.256Z',data: { PM1: 689.325,CO: 47.849 } },{ t: '2020-09-03T09:52:22.233Z',data: { PM1: 200,PM10: 200 } },{ t: '2020-09-03T09:55:32.124Z',PM10: 800 } }
]

我想向结果数组中的每个对象添加一个名为station_name的成员，该成员类似于data.station.name中的原始成员。

有什么建议吗？

谢谢。

解决方法

data =[
  {
    "id": "AQ103_2020-09-03T06:00:00.000Z","date": "2020-09-03T06:00:00.000Z","station": {
      "name": "AQ103","loc": {
        "type": "Point","coordinates": [
          45,12.45
        ]
      }
    },"samples": [
      {
        "t": "2020-09-03T06:10:57.617Z","data": {
          "PM1": 100,"PM10": 800,"O3": 300
        }
      },{
        "t": "2020-09-03T06:12:00.000Z","O3": 300.25,"NO2": 100.45
        }
      }
    ]
  },{
    "id": "AQ103_2020-09-03T10:00:00.000Z","date": "2020-09-03T07:00:00.000Z","samples": [
      {
        "t": "2020-09-03T07:10:57.617Z","PM10": 800
        }
      }
    ]
  },{
    "id": "AQ103_2020-09-03T09:00:00.000Z","date": "2020-09-03T09:00:00.000Z","samples": [
      {
        "t": "2020-09-03T09:46:55.256Z","data": {
          "PM1": 689.325,"CO": 47.849
        }
      },{
        "t": "2020-09-03T09:52:22.233Z","data": {
          "PM1": 200,"PM10": 200
        }
      }
    ]
  },"station": {
      "name": "AQ101","samples": [
      {
        "t": "2020-09-03T09:55:32.124Z","PM10": 800
        }
      }
    ]
  }
];

let unwindedData = data.map(doc => doc.samples.map(sample => ({
  ...doc,samples: sample
}))).flat();

console.log(unwindedData);

这很好地模拟了$ unwind方法，但不需要lodash。

将每个文档映射到单个示例对象的数组，然后展平。

data.map(doc => doc.samples.map(sample => ({
  ...doc,samples: sample
}))).flat()

注意：在SO上运行的代码段在日志输出中显示为站的参考注释，但实际输出正确。

,

感谢GitGitBoom， 通过进一步阐述您的建议，我得到了以下代码：

let values = obj.map((item)=>{
// if items key is not found do not pass it to the new array
if(item.Object.key != X){
return false
}
return item
})

这恰好提供了我想要的东西：

const obj = {
  APRIL: 35,COMPANY: 'Walmart',FEBUARY: 34,FEBUARY_1: 9,HEADQUARTERS: 'Bentonville,AR',JANUARY: 22.6,MARCH: 23.4,MAY: 21.1,TOTAL: 145.1,};

const notInclude = ['COMPANY','HEADQUARTERS','TOTAL'];

let labelValues = () => {
  return Object.keys(obj).filter((val) => !notInclude.includes(val));
};

const data = labelValues();
const result = data.map((val) => obj[val]);

console.log(data);
console.log(result);