如何按天，周，月分组具有时间戳属性的对象？ [英] How to group objects with timestamps properties by day, week, month?

问题描述

在nodejs应用程序中，我有一个事件对象数组，格式如下：

In a nodejs application, I have an array of event objects formatted as follows:

eventsArray = [ {id: 1, date: 1387271989749 }, {id:2, date: 1387271989760}, ... ]

eventsArray具有可变长度的n个元素，假设我选择时间参考为巴黎时间，我希望能够按天，周或月分组元素：

eventsArray having a variable length of n elements, and supposing I choose time reference to be Paris time, I want to be able to group elements by day, week, or month:

groupedByDay = {

            2012: { ... },
            2013: {
              dayN  : [{id: a0, date: b0}, {id: a1, date: b1}, {id: a2, date: b2 }],
              dayN+1: [{id: a3, date: b3}, {id: a4, date: b4}, {id: a5, date: b5 }],
              ...
                   },
            2014: { ... }

          }

groupedByWeek = {
            2012: { ... }
            2013: {
              weekN: [{id: a0, date: b0}, {id: a1, date: b1}, {id: a2, date: b2 }],
              weekN+1: [{id: a3, date: b3}],
              ....
                  },
             2014: { ... }
                }

groupedByMonth = {
             2012: { ... },
             2013: {
               monthN: [ {id: a0, date: b0 }, {id: a1, b1}, {id: a2, b2}, {id: a3, b3 }],
               monthN+1: [ {id: a4, date: b4 }, {id: a5, b5}, {id: a6, b6}],
               ...
                   },
              2014: { ... }
                 }

在操作unix时间戳方面经验很少，我想知道如何做到这一点，或者是否有一个npm模块可以使这更容易。

Having very little experience with manipulating unix timestamps, I was wondering how this could be done or if there was an npm module that would make this easier.

推荐答案

这是我的解决方案。请记住，日期，周和月相对于原点，因为纪元：

Here is my solution. Keep in mind that day, week and month are relative to origin, since epoch:

eventsArray = [ {id: 1, date: 1387271989749 }, {id:2, date: 1387271989760} ];
byday={};
byweek={};
bymonth={};
function groupday(value, index, array)
{
    d = new Date(value['date']);
    d = Math.floor(d.getTime()/(1000*60*60*24));
    byday[d]=byday[d]||[];
    byday[d].push(value);
}
function groupweek(value, index, array)
{
    d = new Date(value['date']);
    d = Math.floor(d.getTime()/(1000*60*60*24*7));
    byweek[d]=byweek[d]||[];
    byweek[d].push(value);
}
function groupmonth(value, index, array)
{
    d = new Date(value['date']);
    d = (d.getFullYear()-1970)*12 + d.getMonth();
    bymonth[d]=bymonth[d]||[];
    bymonth[d].push(value);
}
eventsArray.map(groupday);
eventsArray.map(groupweek);
eventsArray.map(groupmonth);

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