根據月份中的周的間隔過濾和映射資料

我有一個物件陣列，每個物件都有四個屬性（id、start、end 和 amount）。

然后根據這些資料，我創建了一個具有以下屬性的新物件陣列：日期、持續時間和數量。日期是開始屬性的時間戳的日期，持續時間是開始時間戳和結束時間戳之間的時間（以分鐘為單位）。

然后我創建了兩個變數，一個來自所選月份，另一個來自所選年份。然后根據選定的月份和年份過濾陣列日期。例如，如果選擇了 11 月，我只想要日期從 11 月開始的物件。這同樣適用于年份。最終結果是根據所選月份和年份的天數串列。

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，除了按天列出陣列的元素（這是我目前擁有的結果）。我想使用filteredBySelectedDate陣列按周過濾。換句話說，我想根據一個月的周數范圍對陣列的元素進行分組。像這樣的陣列：

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

uj5u.com熱心網友回復：

這可以通過幾個步驟來完成。首先，通過為一個月中的每個星期建立已知的開始/結束天數 ( weekTransitionDays)。其次是識別條目屬于哪一周的方法（getWeekIndex）。最后是將同一周的條目折疊在一起的方法 ( groupByWeek)。

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();
let start = 1;
if (firstDayOfMonth !== 0) {
  let end = start   6 - firstDayOfMonth;
  weekTransitionDays.push([start, end]);
  start = end;
}
while (start < daysInMonth) {
  let end;
  if (start   1 < daysInMonth) {
    start  ;
  } else {
    break;
  }
  if (start   6 < daysInMonth) {
    end = start   6;
  } else {
    break;
  }
  weekTransitionDays.push([start, end]);
  start = end;
}
if (weekTransitionDays.at(-1)[1] !== daysInMonth) {
  weekTransitionDays.push([start, daysInMonth]);
}

const getWeekIndex = entry => {
  const entryStart = new Date(entry.start).getDate();
  for (let i = 0; i < weekTransitionDays.length; i  ) {
    if (weekTransitionDays[i][0] <= entryStart && entryStart <= weekTransitionDays[i][1]) {
      return i;
    }
  }
};

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)) {
      let [start, end] = weekTransitionDays[entry.weekIndex];
      if (start < 10) {
        start = "0"   start;
      }
      if (end < 10) {
        end = "0"   end;
      }
      start = selectedMonth   "/"   start;
      end = selectedMonth   "/"   end;
      obj[entry.weekIndex] = {
        interval: start   ' - '   end,
        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);

標籤：javascript 数组 打字稿 javascript对象

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