如何将每日数据对象变成每月对象

Question

所以我有一个问题如何转动这个对象:

let data = [
{"branch": "london", "date": "2020-05-07", "sales": 500},
{"branch": "london", "date": "2020-05-08", "sales": 1500},
{"branch": "london", "date": "2020-05-09", "sales": 1000},
{"branch": "london", "date": "2020-06-09", "sales": 1000},
{"branch": "wales", "date": "2020-05-10", "sales": 2000},
{"branch": "wales", "date": "2020-05-11", "sales": 3000},
{"branch": "wales", "date": "2020-06-12", "sales": 2500},
{"branch": "wales", "date": "2020-08-12", "sales": 1500}
]

进入那个对象：

let monthlyData = [
{"branch": "london", "date": "2020-05", "sales": 3000},
{"branch": "london", "date": "2020-06", "sales": 1000},
{"branch": "wales", "date": "2020-05", "sales": 5000},
{"branch": "wales", "date": "2020-06", "sales": 2500},
{"branch": "wales", "date": "2020-08", "sales": 1500},
]

所以我的目标是让每个分行给我一个月度记录而不是每天如何解决这个问题，因为我只是设法解决了这个问题，但是日期和销售额扩展了当前对象，而不是用新的月份数据创建一个新对象。

Answer 1

你可以用 Array.prototype.reduce():

const data = [
  {"branch": "london", "date": "2020-05-07", "sales": 500},
  {"branch": "london", "date": "2020-05-08", "sales": 1500},
  {"branch": "london", "date": "2020-05-09", "sales": 1000},
  {"branch": "london", "date": "2020-06-09", "sales": 1000},
  {"branch": "wales", "date": "2020-05-10", "sales": 2000},
  {"branch": "wales", "date": "2020-05-11", "sales": 3000},
  {"branch": "wales", "date": "2020-06-12", "sales": 2500},
  {"branch": "wales", "date": "2020-08-12", "sales": 1500}
];

const monthlyData=Object.values(data.reduce((a,c)=>{ 
 const bd=c.branch+c.date.substr(0,7);             // generate a unique key for branch and month
 if (!a[bd]) a[bd]={...c,date:c.date.substr(0,7)}; // create an entry for bd
 else a[bd].sales+=c.sales;                        // add sales to existing bd entry
 return a;                                         // Object.values: create an array by
},{}));                                            // extracting all values from the object

console.log(monthlyData)

更新：

起初我没有发现 branch 属性。此问题现已修复。

Answer 2

我通过对每个循环使用 2 个解决了这个问题

let data = [
    {"branch": "london", "date": "2020-05-07", "sales": 500},
    {"branch": "london", "date": "2020-05-08", "sales": 1500},
    {"branch": "london", "date": "2020-05-09", "sales": 1000},
    {"branch": "london", "date": "2020-06-09", "sales": 1000},
    {"branch": "wales", "date": "2020-05-10", "sales": 2000},
    {"branch": "wales", "date": "2020-05-11", "sales": 3000},
    {"branch": "wales", "date": "2020-05-12", "sales": 2100},
    {"branch": "wales", "date": "2020-06-12", "sales": 2500},
    {"branch": "wales", "date": "2020-08-12", "sales": 1500},
    {"branch": "wales", "date": "2020-09-12", "sales": 200},
]
monthlyData = []

data.forEach((dataSet) => {
    if (monthlyData.length === 0) {
        newObj = {
            "branch": dataSet.branch,
            "date": dataSet.date.substring(0,7),
            "sales": dataSet.sales
        }
        monthlyData.push(newObj)
    } else {
        let found = false
        monthlyData.forEach((month) => {
            if (month.branch === dataSet.branch && month.date === dataSet.date.substring(0,7)) {
                month.sales += dataSet.sales
                found = true
            }
        })
        if (!found) {
            newObj = {
                "branch": dataSet.branch,
                "date": dataSet.date.substring(0,7),
                "sales": dataSet.sales
            }
            monthlyData.push(newObj)
        }
    }
})

如何将每日数据对象变成每月对象

how to turn a daily data object into a monthly object

javascript

arrays

javascript-objects