按 lodash 中的多个字段分组和排序答案

【问题标题】：Group and Sort by multiple fields in lodash按 lodash 中的多个字段分组和排序
【发布时间】：2021-09-24 11:59:23
【问题描述】：

假设这个数组：

[
    { department: "D1", section: "S1", name: "Test", other: "value", hierarchy: 1 },
    { department: "D2", section: "S1", name: "Test", other: "value", hierarchy: 1 },
    { department: "D2", section: "S2", name: "Test", other: "value", hierarchy: 2 }
]

我想按部门、部门对数据进行分组并对部门、部门、层次结构进行排序

结果是：

[
  "D1": [
     "S1": [
       { name: "Test", other: "value" }
     ]
  ],
  "D2": [
     "S1" [
       { name: "Test", other: "value" }
     ],
     "S2" [
       { name: "Test", other: "value" },
       { name: "Test", other: "value" }
     ]
  ]
]

这是我前进方向的骨架：

var grouped = _.mapValues(_.chain(data).sortBy(item => item.hierarchy).groupBy(item => item.department).value(),
                      clist => clist.map(data => _.omit(data, 'department')));

_.forEach(grouped, function (item, department) {
    const members = _.groupBy(item, (item) => {
         return [item['section'], item['name']];
    });
});

有没有更好的方法来使用 Lodash 实现它？

【问题讨论】：

您的结果不是有效的 javascript。

标签： javascript arrays sorting lodash

【解决方案1】：

您可以在原版 javascript 中使用 sort() 和 reduce() 来实现此目的。

const
  input = [
    { department: "D2", section: "S1", name: "Test-d2-s1-h1", other: "value", hierarchy: 1 },
    { department: "D2", section: "S2", name: "Test-d2-s2-h2", other: "value", hierarchy: 2 },
    { department: "D1", section: "S1", name: "Test-d1-s1-h1", other: "value", hierarchy: 1 },
    { department: "D2", section: "S2", name: "Test-d2-s2-h1", other: "value", hierarchy: 1 },
  ],

  result = input
    .sort((a, b) =>
      a.department.localeCompare(b.department)
      || a.section.localeCompare(b.section)
      || a.hierarchy - b.hierarchy)
    .reduce((a, { department, section, hierarchy, ...data }) => (
      ((a[department] ??= {})[section] ??= []).push(data), a
    ), {});

console.log(result)

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

【讨论】：

【解决方案2】：

我建议使用_.groupBy，然后使用_.mapValues。

groupBy 调用会按部门分组，然后我们使用 mapValues 再次使用 groupBy 将每个部门分组。

const arr = [
    { department: "D1", section: "S1", name: "Test", other: "value", hierarchy: 1 },
    { department: "D2", section: "S2", name: "Test", other: "value", hierarchy: 2 },
    { department: "D2", section: "S1", name: "Test", other: "value", hierarchy: 1 },
    { department: "D2", section: "S2", name: "Test", other: "value", hierarchy: 2 }
]
const result = _.mapValues(_.groupBy(arr, 'department'), (v,k) => _.groupBy(v, 'section'));

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

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【讨论】：