使用 Map、Reduce、Aggregate 的 Javascript JSON 转换

Question

我正在拼命想弄清楚这种转变。

这是 JSON 的格式

我有：

{
    "itineraryId": "063fc878-b118-49fc-9106-39d51f647c9e",
    "reservations": [
        {
            "confirmNumber": "54047SC008976",
            "startDate": "2021-11-20T00:00:00.000Z"
        },
        {
            "confirmNumber": "54047SC008975",
            "startDate": "2021-11-13T00:00:00.000Z"
        },
        {
            "confirmNumber": "54058SC007379",
            "startDate": "2021-08-13T00:00:00.000Z"
        }
    ]
}

我需要：

[{
    "itineraryId": "063fc878-b118-49fc-9106-39d51f647c9e",
    "month": "November 2021",
    "reservations": [{
            "confirmNumber": "54047SC008976",
            "startDate": "2021-11-20T00:00:00.000Z"
        },
        {
            "confirmNumber": "54047SC008975",
            "startDate": "2021-11-13T00:00:00.000Z"
        }
    ]
}, {
    "itineraryId": "063fc878-b118-49fc-9106-39d51f647c9e",
    "month": "August 2021",
    "reservations": [{
        "confirmNumber": "54058SC007379",
        "startDate": "2021-08-13T00:00:00.000Z"
    }]
}]

我需要这样才能在我的react native app 中构建一个SectionList。我尝试了很多不同的选项（聚合+映射+减少），但我无法将其转换为这种格式。有什么指南可以帮助我吗？

---

这个问题要复杂得多，但我通过删除所有不需要的数据属性来简化它。通过查看 SectionList 页面中的示例并找出

的结构，我能够找出我需要的结构

编辑：粘贴当我遵循其中一种解决方案时的样子的图片。 2022 年 11 月出现在 2021 年 11 月之前

Answer 1

我经常希望在 JavaScript 中提供某种简单的“分组依据”功能，但您可以使用 reduce() 实现相同的效果。本质上，您可以通过创建或更新组来构建一组分组结果，具体取决于在每次调用 reducer 函数期间它是否已经存在：

const monthNames = ["January", "February", "March", "April", "May", "June",
  "July", "August", "September", "October", "November", "December"
];

const initial = {
  "itineraryId": "063fc878-b118-49fc-9106-39d51f647c9e",
  "reservations": [{
      "confirmNumber": "54047SC008976",
      "startDate": "2021-11-20T00:00:00.000Z"
    },
    {
      "confirmNumber": "54047SC008975",
      "startDate": "2021-11-13T00:00:00.000Z"
    },
    {
      "confirmNumber": "54058SC007379",
      "startDate": "2021-08-13T00:00:00.000Z"
    },
    {
      "confirmNumber": "54047SC008971",
      "startDate": "2020-11-13T00:00:00.000Z"
    },
    {
      "confirmNumber": "54047SC008973",
      "startDate": "2022-11-13T00:00:00.000Z"
    }
  ]
};

const groupedReservations = initial.reservations
  .sort((reservationA, reservationB) => {
    // Sort descending according to startDate
    return new Date(reservationB.startDate) - new Date(reservationA.startDate);
  })
  .reduce((reservationGroups, reservation) =>
  {
    // Calculate the key that uniquely identifies the group, then look it up
    const date = new Date(reservation.startDate);
    const reservationMonth = monthNames[date.getMonth()] + " " + date.getFullYear();
    const existingGroup = reservationGroups.find(group => group.month === reservationMonth);

    // If the group doesn't exist, create it - otherwise, add the reservation to it
    if (!existingGroup) {
      reservationGroups.push({
        itineraryId: initial.itineraryId,
        month: reservationMonth,
        reservations: [reservation]
      });
    } else {
      existingGroup.reservations.push(reservation);
    }

    return reservationGroups;
  }, []);

console.log(groupedReservations);

请注意，我在这里基本上将itineraryId 视为事后的想法，因为非规范化数据似乎不是一个重要的步骤。如果您的代码上下文需要不同的内容，请告诉我。

Answer 2

这里是缩小的实现

// Convert ISO date to human readable date : August 2021

const formatYearMonth = (dateISO) => {
 
const formatYearMonth = (dateISO) => {

  const monthNames = ["January", "February", "March", "April", "May", "June",
  "July", "August", "September", "October", "November", "December"
];
  const parsedDate =  new Date(dateISO)

  const year = parsedDate.getFullYear()
  const month = monthNames[parsedDate.getMonth()]

  return `${month} ${year}`;
};

  return `${month} ${year}`;
};

const getItineraryMonths = (reservations) => {
  let months = {};

  reservations.forEach((reservation) => {
    const formattedMonth = formatYearMonth(reservation.startDate);

    months[formattedMonth] = formattedMonth;
  });

  return Object.keys(months);
};

// Get reservation in specified month for specific itinerary

const getReservationsInMonth = (reservations, formatedMonthIn) => {
  return reservations.filter((reservation) => {
    const formattedMonth = formatYearMonth(reservation.startDate);

    return formattedMonth === formatedMonthIn;
  });
};

// Reformat JSON response

const formatJsonResponse = (response) => {
  const itineraryMonths = getItineraryMonths(response.reservations);

  const formattedResult = itineraryMonths.map((month) => {
    return {
      itineraryId: response.itineraryId,
      month,
      reservations: getReservationsInMonth(response.reservations, month),
    };
  });

  return formattedResult;
};

console.log(formatJsonResponse(input));

测试解决方案-https://replit.com/@EmmanuelBYIRING/json-sanitise#index.js