如何在 foreach javascript 中对数据进行分组和求和

Question

我有一个数组对象形式的数据。我将数据分组并根据日期和代码求和

const data = [
{code: 8, date:"2022-03-24", total:4},
{code: 8, date:"2022-03-24", total:8},
{code: 8, date:"2022-03-25", total:2},
{code: 9, date:"2022-03-24", total:4},
{code: 9, date:"2022-03-25", total:2},
{code: 9, date:"2022-03-25", total:1},]

结果在意料之中

const result = [
{code: 8, date:"2022-03-24", total:12},
{code: 8, date:"2022-03-25", total:2},
{code: 9, date:"2022-03-24", total:4},
{code: 9, date:"2022-03-25", total:3},]

Answer 1

您通常可以使用 reduce 来解决这些分组问题。我正在使用 code 和 date 的组合进行分组。像 "8|2022-03-24".

这就是中间对象的样子

{
  8|2022-03-24: {
    code: 8,
    date: "2022-03-24",
    total: 12
  },
  8|2022-03-25: {
    code: 8,
    date: "2022-03-25",
    total: 2
  },
  9|2022-03-24: {
    code: 9,
    date: "2022-03-24",
    total: 4
  },
  9|2022-03-25: {
    code: 9,
    date: "2022-03-25",
    total: 3
  }
}

我正在使用 Object.values

从该对象获取值

const data = [
{code: 8, date:"2022-03-24", total:4},
{code: 8, date:"2022-03-24", total:8},
{code: 8, date:"2022-03-25", total:2},
{code: 9, date:"2022-03-24", total:4},
{code: 9, date:"2022-03-25", total:2},
{code: 9, date:"2022-03-25", total:1},]

let grouped = Object.values(data.reduce((acc,{code,date,total})=>{
    acc[code+'|'+date] = acc[code+'|'+date] || {code,date,total:0}
  acc[code+'|'+date].total+=total
  return acc;
},{}))

console.log(grouped)

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