如何在foreach javascript中对数据进行分组和求和[duplicate]

Question

我有一个数组对象形式的数据。我将根据日期和代码对数据进行分组和汇总

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},]

预期结果

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

通常对于这些分组问题，您可以使用减少。我将code和date的组合进行分组。类似于"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
  }
}

从这个对象中，我使用对象获取值。值

js lang-js prettyprint-override">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)