使用 Lodash 的对象数组中的多个 groupBy 和 sumBy答案

【问题标题】：Multiple groupBy and sumBy in array of objects using Lodash使用 Lodash 的对象数组中的多个 groupBy 和 sumBy
【发布时间】：2021-10-28 04:51:39
【问题描述】：

我有以下数据：

const rawData=[
  {
    Order_Date: "2020-08-11",
    Region: "South",
    Product_Name: "Bookcase",
    Sales: 261.96
  },
  {
    Order_Date: "2020-08-13",
    Region: "South",
    Product_Name: "Stacking Chairs",
    Sales: 731.94
  },
  {
    Order_Date: "2020-10-06",
    Region: "South",
    Product_Name: "Stacking Chairs",
    Sales: 700.45
  },
  {
    Order_Date: "2020-12-06",
    Region: "East",
    Product_Name: "Self-Adhesive Address Labels for Typewriters by Universal",
    Sales: 14.62
  },
  {
    Order_Date: "2019-11-15",
    Region: "East",
    Product_Name: "Table",
    Sales: 957
  },
  {
    Order_Date: "2019-11-10",
    Region: "East",
    Product_Name: "Eldon Fold",
    Sales: 22
  }
]

预期输出：

[
    {
      Region: "South",
      data: [
        {
           Order_Date: "2020-08",
           Sales: 993.90
        },
        {
          Order_Date: "2020-10",
          Sales: 700.45
        },
      ]
    },
    {
      Region: "East",
      data: [
        {
           Order_Date: "2019-11",
           Sales: 989
        },
        {
          Order_Date: "2020-12",
          Sales: 14.62
        },
      ]
    }
]

我想首先按地区分组，对于每个地区我想按 Order_Date 的年月 ('YYYY-MM') 分组，然后按每个 Order_Date('YYYY-MM') 组的销售额求和。

我尝试了以下代码，但无法获得预期的输出。我不明白如何通过多个分组来做到这一点。

const groupByRegion = _(rawData).groupBy('Region').value();

const groupByRegionDate = _.forEach(groupByRegion, (value, key) => {
        groupByRegion[key] = _.groupBy(groupByRegion[key], (item) =>
            moment(item.Order_Date).startOf('month').format('YYYY-MM')
        );
    });

【问题讨论】：

rawData 不能是“JSON”，因为 JSON 是一种文本格式。因此，这个问题是关于数组和对象，而不是 JSON，所以让我们把它排除在外，好吗？
我只使用item.Order_Date.slice(0, -3) 而不是用时刻解析日期。

标签： javascript arrays object lodash nivo-react

【解决方案1】：

let data = [{ "Order_Date": "2020-08-11", "Region": "South", "Product_Name": "Bookcase", "Sales": 261.96 }, { "Order_Date": "2020-08-11", "Region": "South", "Product_Name": "Stacking Chairs", "Sales": 731.94 }, { "Order_Date": "2020-10-06", "Region": "South", "Product_Name": "Stacking Chairs", "Sales": 700.45 }, { "Order_Date": "2020-12-06", "Region": "East", "Product_Name": "Typewriters by Universal", "Sales": 14.62 }, { "Order_Date": "2019-11-10", "Region": "East", "Product_Name": "Table", "Sales": 957 }, { "Order_Date": "2019-11-10", "Region": "East", "Product_Name": "Eldon Fold", "Sales": 22 }]
let results = []

for (let item of data) {
    let { Region, Order_Date, Sales } = item;
    let group = results.find(v => v.Region == Region);
    if (!group) results.push(group = { Region, data: [] });

    let groupItem = group.data.find(v => v.Order_Date == Order_Date);

    if (!groupItem)
        group.data.push({ Order_Date, Sales })
    else
        groupItem.Sales += Sales;
}

console.log(results)

【讨论】：

非常接近预期的输出。谢谢你的回答。
当然这不是你所期望的100%，因为我故意没有回答100%，并且给你留了一些待办事项（作为练习）......