lodash 过滤对象数组并分组依据创建新数组

Question

下面是主数组，我想按 dept.name 分组并将除“e-depid”之外的所有其他字段删除到单个数组

主数组

  [
    {
      "id": "67",
      "empid": 5,
      "e-depid": "ab",
      "dept": { "name": "Prod" }
    },
    {
      "id": "67",
      "empid": 7,
      "e-depid": "ac",
      "dept": { "name": "Prod" }
    },
    {
      "id": "67",
      "empid": 5,
      "e-depid": "ad",
      "dept": { "name": "mkt" }
    }
  ]

结果数组

  [
    {
      "Prod": { "e-depid": ["ab", "ac"] },
      "mkt": { "e-depid": ["ad"] }
    }
  ]

Answer 1

您可以 .transform 获得想要的结果。

如有必要，将对象包装在数组中。

const
    data = [{ id: "67", empid: 5, "e-depid": "ab", dept: { name: "Prod" } }, { id: "67", empid: 7, "e-depid": "ac", dept: { name: "Prod" } }, { id: "67", empid: 5, "e-depid": "ad", dept: { name: "mkt" } }],
    result = _(data)
        .groupBy(o => o.dept.name)
        .transform((o, a, k) => (o[k] ??= {})['e-depid'] = a.map(o => o['e-depid']))
        .value();

console.log(result);

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<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.min.js"></script>

Answer 2

可以通过简单的 Array.prototype.reduce() 调用非常干净。

const
  input = [{ "id": "67", "empid": 5, "e-depid": "ab", "dept": { "name": "Prod" } }, { "id": "67", "empid": 7, "e-depid": "ac", "dept": { "name": "Prod" } }, { "id": "67", "empid": 5, "e-depid": "ad", "dept": { "name": "mkt" } }],

  result = input.reduce((a, { dept: { name }, 'e-depid': e }) => (
    (a[name] || (a[name] = { 'e-depid': [] }))['e-depid'].push(e), a
  ), {});

console.log(result);

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原始答案使用 logical nullish assignment (??=)

const
  input = [{ "id": "67", "empid": 5, "e-depid": "ab", "dept": { "name": "Prod" } }, { "id": "67", "empid": 7, "e-depid": "ac", "dept": { "name": "Prod" } }, { "id": "67", "empid": 5, "e-depid": "ad", "dept": { "name": "mkt" } }],

  result = input.reduce((a, { dept: { name }, 'e-depid': e }) => (
    (a[name] ??= { 'e-depid': [] })['e-depid'].push(e), a
  ), {})

console.log(result);

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