如何在空陣列上呼叫reduce并分配新屬性

我有一個具有默認屬性的物件和兩個陣列，其中一個是空的。空陣列在某些情況下可能不為空，但我仍然想回圈它。如果陣列為空，reduce 將不會被呼叫，并且我會丟失一些屬性，所以想法是在物件中有一些默認屬性以防陣列為空。預期的結果是這樣的：

[{
  "playedOffTickets": 60,
  "playedOffRevenue": 1730.5,
  "Transactions.deliveryMethod": "Print At Home Delivery",
  "soldTickets": 0,
  "soldRevenue": 0,
 },
 {
  "playedOffTickets": 43,
  "playedOffRevenue": 1160,
  "Transactions.deliveryMethod": "Postal Delivery",
  "soldTickets": 0,
  "soldRevenue": 0,
 },
 {
  "playedOffTickets": 12,
  "playedOffRevenue": 348,
  "Transactions.deliveryMethod": "Cobo Delivery",
  "soldTickets": 0,
  "soldRevenue": 0,
 },
 {
  "playedOffTickets": -3,
  "playedOffRevenue": -87,
  "Transactions.deliveryMethod": "",
  "soldTickets": 0,
  "soldRevenue": 0,
}];

但我得到的回應不是我想要的。我究竟做錯了什么？提前致謝！

const productMap = {
      soldTickets: 0,
      soldRevenue: 0,
      playedOffTickets: 0,
      playedOffRevenue: 0,
    };

    const arr1 = [];
    const arr2 = [
      {
         "Transactions.deliveryMethod": "Print At Home Delivery",
         "Transactions.itemCount": "60",
         "Transactions.revenue": "1730.5"
      },
      {
         "Transactions.deliveryMethod": "Postal Delivery",
         "Transactions.itemCount": "43",
         "Transactions.revenue": "1160"
      },
      {
         "Transactions.deliveryMethod": "Cobo Delivery",
         "Transactions.itemCount": "12",
         "Transactions.revenue": "348"
      },
      {
         "Transactions.deliveryMethod": "",
         "Transactions.itemCount": "-3",
         "Transactions.revenue": "-87"
      }
    ];

    arr1.reduce((p, salesData) => {
      const product = salesData["Transactions.deliveryMethod"];
      p[product] = p[product] || {};
      const soldTickets = Number(salesData["Transactions.itemCount"]);
      const soldRevenue = Number(salesData["Transactions.revenue"]);

      p[product].soldTickets = p[product].soldTickets || 0;
      p[product].soldTickets  = soldTickets;

      p[product].soldRevenue = p[product].soldRevenue || 0;
      p[product].soldRevenue  = soldRevenue;

      p[product]["Transactions.deliveryMethod"] = product;

      return p;
    }, productMap);

    arr2.reduce((p, playedOffData) => {
      const product = playedOffData["Transactions.deliveryMethod"];
      p[product] = p[product] || {};
      const playedOffTickets = Number(playedOffData["Transactions.itemCount"]);
      const playedOffRevenue = Number(playedOffData["Transactions.revenue"]);

      p[product].playedOffTickets = p[product].playedOffTickets || 0;
      p[product].playedOffTickets  = playedOffTickets;

      p[product].playedOffRevenue = p[product].playedOffRevenue || 0;
      p[product].playedOffRevenue  = playedOffRevenue;

      p[product]["Transactions.deliveryMethod"] = product;

      return p;
    }, productMap);

    const productMapData = Object.values(productMap);
    
    console.log(productMapData)

uj5u.com熱心網友回復：

我建議添加一個productMapDefaults物件，只要我們想在 productMap 物件中創建一個新條目，我們就會使用它。

然后可以根據需要進行自定義以添加新屬性。

const productMap = {};

const productMapDefaults = { 
    soldTickets: 0,
    soldRevenue: 0,
    playedOffTickets: 0,
    playedOffRevenue: 0
}

const arr1 = [];
const arr2 = [
  {
     "Transactions.deliveryMethod": "Print At Home Delivery",
     "Transactions.itemCount": "60",
     "Transactions.revenue": "1730.5"
  },
  {
     "Transactions.deliveryMethod": "Postal Delivery",
     "Transactions.itemCount": "43",
     "Transactions.revenue": "1160"
  },
  {
     "Transactions.deliveryMethod": "Cobo Delivery",
     "Transactions.itemCount": "12",
     "Transactions.revenue": "348"
  },
  {
     "Transactions.deliveryMethod": "",
     "Transactions.itemCount": "-3",
     "Transactions.revenue": "-87"
  }
];

arr1.reduce((p, salesData) => {
  const product = salesData["Transactions.deliveryMethod"];
  // Use productMapDefaults as template when creating new entry...
  p[product] = p[product] || { ...productMapDefaults };
  const soldTickets = Number(salesData["Transactions.itemCount"]);
  const soldRevenue = Number(salesData["Transactions.revenue"]);

  p[product].soldTickets = p[product].soldTickets || 0;
  p[product].soldTickets  = soldTickets;

  p[product].soldRevenue = p[product].soldRevenue || 0;
  p[product].soldRevenue  = soldRevenue;

  p[product]["Transactions.deliveryMethod"] = product;

  return p;
}, productMap);

arr2.reduce((p, playedOffData) => {
  const product = playedOffData["Transactions.deliveryMethod"];
  // Use productMapDefaults as template when creating new entry...
  p[product] = p[product] || { ...productMapDefaults };
  const playedOffTickets = Number(playedOffData["Transactions.itemCount"]);
  const playedOffRevenue = Number(playedOffData["Transactions.revenue"]);

  p[product].playedOffTickets = p[product].playedOffTickets || 0;
  p[product].playedOffTickets  = playedOffTickets;

  p[product].playedOffRevenue = p[product].playedOffRevenue || 0;
  p[product].playedOffRevenue  = playedOffRevenue;

  p[product]["Transactions.deliveryMethod"] = product;

  return p;
}, productMap);

const productMapData = Object.values(productMap);
console.log(productMapData)
    

.as-console-wrapper { max-height: 100% !important; top: 0; }

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