根据月份的周间隔过滤和映射数据

Question

我有一个对象数组，每个对象都有四个属性（id、start、end 和 amount）。

然后根据这些数据创建一个新的对象数组，该数组具有以下属性：日期、持续时间和金额。 date 是 start 属性的时间戳的日期，duration 是 start 时间戳和 end 时间戳之间的时间，以分钟为单位。

然后我创建了两个变量，一个来自所选月份，另一个来自所选年份。然后根据选定的月份和年份过滤数组日期。例如，如果选择了第 11 个月，我只想要日期从第 11 个月开始的对象。这同样适用于年份。最终结果是根据所选月份和年份的日期列表。

const arrayOfDates = [
    {
        id: 1,
        start: '2021-12-01T12:10:56+0000',
        end: '2021-12-01T12:00:56+0000',
        amount: 10
    },
    {
        id: 2,
        start: '2021-12-03T11:10:56+0000',
        end: '2021-12-03T12:45:56+0000',
        amount: 4
    },
    {
        id: 3,
        start: '2021-12-07T09:10:56+0000',
        end: '2021-12-07T09:25:56+0000',
        amount: 8
    },
    {
        id: 4,
        start: '2021-11-24T11:10:56+0000',
        end: '2021-11-24T11:25:56+0000',
        amount: 8
    }
]

const selectedMonth = 12
const selectedYear = 2021

const mapped = arrayOfDates.map((el) => ({
    date: new Date(el.start).toLocaleDateString('en-CA'),
    duration: new Date(new Date(el.end).getTime() - new Date(el.start).getTime()).getMinutes(),
    amount: el.amount
}))

const filteredBySelectedDate = mapped.filter((el) => {
    var [year, month] = el.date.split('-')
    return selectedMonth === +month && selectedYear === +year;
})

const mappedByDays = filteredBySelectedDate

但是，除了按天列出数组的元素（这是我目前的结果）。我想使用filteredBySelectedDate 数组按周过滤。换句话说，我想根据一个月的周数范围对数组的元素进行分组。像这样的数组：

const mappedByWeeks = [
    {
        interval: '12/01 - 12/04',
        duration: 85,
        amount: 14
    },
    {
        interval: '12/05 - 12/11',
        duration: 15,
        amount: 8
    }
]

Answer 1

这可以通过几个步骤来完成。首先，为每个月的每个星期建立已知的开始/结束日期 (weekTransitionDays)。其次，一种识别条目属于哪一周的方法（getWeekIndex）。最后是一种将同一周的条目折叠在一起的方法 (groupByWeek)。

编辑

添加了用于创建间隔文本的辅助函数。

const arrayOfDates = [{
    id: 1,
    start: '2021-12-01T12:10:56+0000',
    end: '2021-12-01T12:00:56+0000',
    amount: 10
  },
  {
    id: 2,
    start: '2021-12-03T11:10:56+0000',
    end: '2021-12-03T12:45:56+0000',
    amount: 4
  },
  {
    id: 3,
    start: '2021-12-07T09:10:56+0000',
    end: '2021-12-07T09:25:56+0000',
    amount: 8
  },
  {
    id: 4,
    start: '2021-11-24T11:10:56+0000',
    end: '2021-11-24T11:25:56+0000',
    amount: 8
  }
];

const selectedMonth = 12;
const selectedYear = 2021;

const weekTransitionDays = [];
const firstDayOfMonth = (new Date(selectedYear, selectedMonth - 1, 1)).getDay();
const daysInMonth = (new Date(selectedYear, selectedMonth, 0)).getDate();

const getInterval = (start, end) => {
  if (start < 10) {
    start = "0" + start;
  }
  if (end < 10) {
    end = "0" + end;
  }
  start = selectedMonth + "/" + start;
  end = selectedMonth + "/" + end;
  return start + ' - ' + end;
};

let start = 1;
if (firstDayOfMonth !== 0) {
  let end = start + 6 - firstDayOfMonth;
  const interval = getInterval(start, end);
  weekTransitionDays.push({
    start,
    end,
    interval
  });
  start = end;
}

while (start < daysInMonth) {
  let end;
  if (start + 1 < daysInMonth) {
    start++;
  } else {
    break;
  }
  if (start + 6 < daysInMonth) {
    end = start + 6;
  } else {
    break;
  }
  const interval = getInterval(start, end);
  weekTransitionDays.push({
    start,
    end,
    interval
  });
  start = end;
}

if (weekTransitionDays.at(-1).end !== daysInMonth) {
  const end = daysInMonth;
  const interval = getInterval(start, end);
  weekTransitionDays.push({
    start,
    end,
    interval
  });
}

const getWeekIndex = entry => {
  const entryStart = new Date(entry.start).getDate();
  for (let i = 0; i < weekTransitionDays.length; i++) {
    if (weekTransitionDays[i].start <= entryStart && entryStart <= weekTransitionDays[i].end) {
      return i;
    }
  }
  // Throw error if start date doesn't line up
  throw new Error("entry.start mismatch with transition days: \n" + JSON.stringify(entry) + "\n" + JSON.stringify(weekTransitionDays));
};

const mapped = arrayOfDates.map((el) => ({
  date: new Date(el.start).toLocaleDateString('en-CA'),
  duration: new Date(new Date(el.end).getTime() - new Date(el.start).getTime()).getMinutes(),
  weekIndex: getWeekIndex(el),
  amount: el.amount
}));

const filteredBySelectedDate = mapped.filter((el) => {
  var [year, month] = el.date.split('-');
  return selectedMonth === +month && selectedYear === +year;
});

const groupByWeek = () => {
  const obj = {};
  filteredBySelectedDate.forEach(entry => {
    if (!obj.hasOwnProperty(entry.weekIndex)) {
      obj[entry.weekIndex] = {
        interval: weekTransitionDays[entry.weekIndex].interval,
        duration: 0,
        amount: 0
      };
    }
    obj[entry.weekIndex].duration += entry.duration;
    obj[entry.weekIndex].amount += entry.amount;
  });
  return Object.values(obj);
};

const mappedByDays = filteredBySelectedDate;
const groupedByWeek = groupByWeek(mapped);

console.log(groupedByWeek);