將陣列中具有相同id但總和的物件合并

我目前有一個看起來像這樣的物件陣列：

const orders = [
  { id: '1', userId: '3', total: 300 },
  { id: '2', userId: '4', total: 200 },
  { id: '3', userId: '5', total: 101 },
  { id: '4', userId: '6', total: 80 },
  { id: '5', userId: '7', total: 76 },
  { id: '6', userId: '8', total: 44 },
  { id: '7', userId: '9', total: 1000 },
  { id: '8', userId: '10', total: 99 },
  { id: '9', userId: '3', total: 65 },
  { id: '10', userId: '4', total: 22 }
];

我將如何組合陣列中共享相同 userId 的任何物件的總數？

我希望我的結果是這樣的：

const newOrdersArray = [
  { id: '1', userId: '3', total: 365 },
  { id: '2', userId: '4', total: 222 },
  { id: '3', userId: '5', total: 101 },
  { id: '4', userId: '6', total: 80 },
  { id: '5', userId: '7', total: 76 },
  { id: '6', userId: '8', total: 44 },
  { id: '7', userId: '9', total: 1000 },
  { id: '8', userId: '10', total: 99 }
];

uj5u.com熱心網友回復：

我不知道這背后的用例，但查看資料，我假設id是特定訂單的id。將其保留在累積結果中感覺有些奇怪，其中總數僅與用戶的所有訂單有關，而不再與單個訂單有關。因此，我會放棄它并像這樣計算總數：

totals = orders.reduce((totals, order) => {
  totals[order.userId] = (totals[order.userId] ?? 0)   order.total;
  return totals;
}, {});

是的，您不再有陣列，而是有一個以 userIds 作為鍵的物件。如果這不適合您的特定用例，只需再次轉換它。

uj5u.com熱心網友回復：

這是一種使用reduce的方法

const orders = [
  { id: '1', userId: '3', total: 300 },
  { id: '2', userId: '4', total: 200 },
  { id: '3', userId: '5', total: 101 },
  { id: '4', userId: '6', total: 80 },
  { id: '5', userId: '7', total: 76 },
  { id: '6', userId: '8', total: 44 },
  { id: '7', userId: '9', total: 1000 },
  { id: '8', userId: '10', total: 99 },
  { id: '9', userId: '3', total: 65 },
  { id: '10', userId: '4', total: 22 }
];

let combined = orders.reduce((b, a) => {
  let index = b.findIndex(arr => arr.userId == a.userId);
  delete a.id
  if (index > -1) b[index].total  = a.total;
  else b.push(a);
  return b;
}, [])

console.log(combined);

uj5u.com熱心網友回復：

嘗試這個：

const orders = [
  { id: '1', userId: '3', total: 300 },
  { id: '2', userId: '4', total: 200 },
  { id: '3', userId: '5', total: 101 },
  { id: '4', userId: '6', total: 80 },
  { id: '5', userId: '7', total: 76 },
  { id: '6', userId: '8', total: 44 },
  { id: '7', userId: '9', total: 1000 },
  { id: '8', userId: '10', total: 99 },
  { id: '9', userId: '3', total: 65 },
  { id: '10', userId: '4', total: 22 }
];

const totals = [];
orders.forEach(x => {
  const obj = totals.find(o => o.userId === x.userId);
  if (obj) {
    obj.total = obj.total   x.total;
  } else {
    totals.push(x);
  }
});

console.log(totals);

uj5u.com熱心網友回復：

您可以使用一個物件進行尋址，userId并從該物件中獲取值作為結果。

const
    orders = [{ id: '1', userId: '3', total: 300 }, { id: '2', userId: '4', total: 200 }, { id: '3', userId: '5', total: 101 }, { id: '4', userId: '6', total: 80 }, { id: '5', userId: '7', total: 76 }, { id: '6', userId: '8', total: 44 }, { id: '7', userId: '9', total: 1000 }, { id: '8', userId: '10', total: 99 }, { id: '9', userId: '3', total: 65 }, { id: '10', userId: '4', total: 22 }],
    result = Object.values(orders.reduce((r, o) => {
        r[o.userId] ??= { ...o, total: 0 };
        r[o.userId].total  = o.total;
        return r;
    }, {}));

console.log(result);

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uj5u.com熱心網友回復：

以下是.reduce()將 ID 收集在每個用戶 ID 的陣列中的方法的一種變體：

const orders = [
  { id: '1', userId: '3', total: 300 },
  { id: '2', userId: '4', total: 200 },
  { id: '3', userId: '5', total: 101 },
  { id: '4', userId: '6', total: 80 },
  { id: '5', userId: '7', total: 76 },
  { id: '6', userId: '8', total: 44 },
  { id: '7', userId: '9', total: 1000 },
  { id: '8', userId: '10', total: 99 },
  { id: '9', userId: '3', total: 65 },
  { id: '10', userId: '4', total: 22 }
];

let combined = Object.values(orders.reduce((a,c) => { 
  let e = (a[c.userId] = a[c.userId] || {ids:[],userId:c.userId,total:0});
  e.total =c.total;
  e.ids.push(c.id);
  return a;
}, {}))

console.log(combined);

標籤：javascript 数组 目的

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