Lodash：如何分组，然后按多个属性对集合进行排序答案

【问题标题】：Lodash: How to group, then sort collection by more than one propertyLodash：如何分组，然后按多个属性对集合进行排序
【发布时间】：2021-04-22 07:27:34
【问题描述】：

如何按多个属性对我的收藏集进行分组和排序？

我的收藏看起来像

const list = [
  {
    transactionId: "Id1",
    amount: 100,
    timestamp: 1619075704230,
    user: "username1",
  },
  {
    transactionId: "Id2",
    amount: 5,
    timestamp: 1619075704230,
    user: "username2",
  },
  {
    transactionId: "Id3",
    amount: 8,
    timestamp: 1619075704230,
    user: "username3",
  },
  {
    transactionId: "Id4",
    amount: 12,
    timestamp: 1619075704230,
    user: "username1",
  },
  {
    transactionId: "Id5",
    amount: 200,
    timestamp: 1619075704230,
    user: "username7",
  },
  {
    transactionId: "Id6",
    amount: 99,
    timestamp: 1619075704230,
    user: "username1",
  },
  {
    transactionId: "Id7",
    amount: 78,
    timestamp: 1619075704230,
    user: "username1",
  },
  {
    transactionId: "Id8",
    amount: 12,
    timestamp: 1619075704230,
    user: "username9",
  },
];

我想按user属性对列表进行分组，然后将接收到的数组按timestamp和amount字段排序。

确切的反应应该是这样的

{
....
  "username1": [
    {
      transactionId: "Id1",
      amount: 100,
      timestamp: 1619075704230,
      user: "username1",
    },
    ,
    {
      transactionId: "Id6",
      amount: 99,
      timestamp: 1619075704230,
      user: "username1",
    },
    {
      transactionId: "Id7",
      amount: 78,
      timestamp: 1619075704230,
      user: "username1",
    },
    {
      transactionId: "Id4",
      amount: 12,
      timestamp: 1619075704230,
      user: "username1",
    }
  ]
  ...
}

【问题讨论】：

标签： javascript node.js lodash

【解决方案1】：

您可以使用groupBy 和orderBy 函数来实现。

const list = [
  {
    transactionId: "Id1",
    amount: 100,
    timestamp: 1619075704230,
    user: "username1",
  },
  {
    transactionId: "Id2",
    amount: 5,
    timestamp: 1619075704230,
    user: "username2",
  },
  {
    transactionId: "Id3",
    amount: 8,
    timestamp: 1619075704230,
    user: "username3",
  },
  {
    transactionId: "Id4",
    amount: 12,
    timestamp: 1619075704230,
    user: "username1",
  },
  {
    transactionId: "Id5",
    amount: 200,
    timestamp: 1619075704230,
    user: "username7",
  },
  {
    transactionId: "Id6",
    amount: 99,
    timestamp: 1619075704230,
    user: "username1",
  },
  {
    transactionId: "Id7",
    amount: 78,
    timestamp: 1619075704230,
    user: "username1",
  },
  {
    transactionId: "Id8",
    amount: 12,
    timestamp: 1619075704230,
    user: "username9",
  },
];

const sorted = _.orderBy(list, ['timestamp', 'amount'], ['desc', 'desc']);

const result = _.groupBy(sort, 'user');

console.log('Result: ', result);

【讨论】：

【解决方案2】：

如果你使用lodash

你可以这样做

let grouped = _.groupBy(list,'user');

let ordered = {};

for (const [key, value] of Object.entries(grouped)) {
  ordered[key] = _.orderBy(value,['timeStamp','amount']);
}

console.log(orderedArray);

【讨论】：