按月对数组进行编号，并在新的月份和年份重置为 1

Question

我有一个数组中的数据，其结构如下

[
    {createdAt: "2022-03-12T13:15:41.844+00:00", "name": 'adipiscing'},
    {createdAt: "2022-03-04T11:56:27.545+00:00", "name": 'consectetur'},
    {createdAt: "2021-01-15T09:12:25.418+00:00", "name": 'amet'},
    {createdAt: "2021-01-09T09:12:25.418+00:00", "name": 'sit'},
    {createdAt: "2021-01-02T08:52:55.418+00:00", "name": 'dolor'},
    {createdAt: "2021-12-15T09:12:25.418+00:00", "name": 'ipsum'},
    {createdAt: "2021-12-11T08:52:55.418+00:00", "name": 'lorem'},
]

以上数据按 createdAt desc 排序。

目前我像往常一样使用索引数据进行编号，我想根据 createdAt 列更改编号，但每次更改月份或在新的月份或年份中输入时，数字都会再次重置为 1

谁能帮帮我，万分感谢

Answer 1

以下可能是实现所需 objective 的一种可能解决方案：

代码段

// helper method to get either YYYY-MM (if full=false) or YYYY-MM-DD (otherwise)
const getDtYMD = (dt, full = false) => (
  full ? dt.createdAt.split('T')[0] : dt.slice(0, 7)
);
// transform the arr to add a group-id (idGroup)
const sortAndGroup = arr => (
  Object.values( // get the values of the result object
    [...arr.map(x => ({...x}))].sort( // first sort the input-array reverse-chronological order (latest date at 0)
      (a, b) => (getDtYMD(a, true) > getDtYMD(b, true) ? 1 : -1)
    ).reduce( // use .reduce to iterate over the sorted array
      (acc, {createdAt : c, name}) => ({
        ...acc, // safe-keep existing accumulator object
        [getDtYMD(c)]: ([
          ...(acc[getDtYMD(c)] || []),
          { // append new object to value array for key YYYY-MM
            idGroup: (acc[getDtYMD(c)]?.length || 0) + 1,
            createdAt: c, // update 'idGroup' based on existing value-array's length
            name
          }
        ])
      }),
      {}
    )
  ).flat().sort(
    (a, b) => (
      getDtYMD(a, true) > getDtYMD(b, true)
      ? -1
      : getDtYMD(a, true) < getDtYMD(b, true)
        ? 1
        : a.idGroup > b.idGroup ? -1 : 1
    )
  )
);


const unsortedRawDataArray = [
    {'createdAt': "2022-03-12T13:15:41.844+00:00", "name": '1 adipiscing'},
    {'createdAt': "2022-03-04T11:56:27.545+00:00", "name": '1 consectetur'},
    {'createdAt': "2022-03-04T11:56:27.545+00:00", "name": '2 consectetur'},
    {'createdAt': "2022-03-04T11:56:27.545+00:00", "name": '3 consectetur'},
    {'createdAt': "2021-01-15T09:12:25.418+00:00", "name": '1 amet'},
    {'createdAt': "2021-01-09T09:12:25.418+00:00", "name": '1 sit'},
    {'createdAt': "2021-01-09T09:12:25.418+00:00", "name": '2 sit'},
    {'createdAt': "2021-01-09T09:12:25.418+00:00", "name": '3 sit'},
    {'createdAt': "2021-01-02T08:52:55.418+00:00", "name": '1 dolor'},
    {'createdAt': "2021-01-02T08:52:55.418+00:00", "name": '2 dolor'},
    {'createdAt': "2021-12-15T09:12:25.418+00:00", "name": '1 ipsum'},
    {'createdAt': "2021-12-11T08:52:55.418+00:00", "name": '1 lorem'},
];

console.log('sorted-grouped: ', sortAndGroup(unsortedRawDataArray));
console.log('original-array: ', unsortedRawDataArray);

说明

步骤说明已作为内联注释添加到上述代码片段中。

编辑

when there is data that has the same date/day the order returns to 1 again,

数组中的数据已更新为具有相同日期的多个数据，并且 idGroup 显示为未重置。

besides is there a way to reverse the number without changing the index, for example from 1-3 to 3-1.

这已在更新的代码段中完成。在 .flat() 之后，我们添加另一个 .sort()，它不仅考虑日期，还考虑 idGroup，以使数字从 3-1（反向）开始。

编辑 2

why after calling the sortAndGroup() function the data from unsortedRawDataArray also changes

此问题已修复。传入的arr（数组）是通过.sort直接变异的，最新版本的答案复制了arr数组。

按月对数组进行编号，并在新的月份和年份重置为 1

Numbering array by month and reset to 1 on new month and year

javascript

arrays

grouping

date-range

reactjs