Lodash:如何使用orderBy对集合进行不区分大小写的排序？

Question

我检查了这个答案但是为了获得相同的结果,即获得不区分大小写的排序,我需要使用orderBy而不是sortBy因为它能够指定排序顺序.

我发现实现它的唯一方法是创建一个映射到小写的克隆"中间"数组name:

const users = [
  { name: 'A', age: 48 },
  { name: 'B', age: 34 },
  { name: 'b', age: 40 },
  { name: 'a', age: 36 }
];

let lowerCaseUsers = _.clone(users);

lowerCaseUsers = lowerCaseUsers.map((user) => {
  user.name = user.name.toLowerCase();
  return user;
});

const sortedUsers = _.orderBy(lowerCaseUsers, ['name'], ['desc']);

console.log(sortedUsers);

这看起来非常昂贵,而且对于多个排序和动态属性名称来说甚至会更复杂.

有更好的主意吗？

---

这是一个Plunker:https://plnkr.co/edit/i1ywyxjFctuNfHtPTcgG

Answer 1

该文档指定您可以将函数作为"iteratee"传递:

[iteratees = [_.identity]](Array [] | Function [] | Object [] | string []):迭代次数排序依据.

所以你可以做到

const users = [
  { name: 'A', age: 48 },
  { name: 'B', age: 34 },
  { name: 'b', age: 40 },
  { name: 'a', age: 36 }
];

const sortedUsers = _.orderBy(users, [user => user.name.toLowerCase()], ['desc']);
console.log(sortedUsers);

<script src="https://cdn.jsdelivr.net/lodash/4.13.1/lodash.min.js"></script>

Answer 2

您可以将 Felix Kling 示例与 _.get 函数结合起来，按动态嵌套属性进行排序：

const _ = require('lodash');

let test = [{ a: {b:'AA'}},{a: {b:'BB'} }, {a: {b: 'bb'}}, {a:{b:'aa'}}];

let attrPath = 'a.b';

_.orderBy(test, [item => _.get(item, attrPath).toLowerCase()]);

Answer 3

Ordering by multiple properties:

const users = [
  { name: 'A', age: 48 },
  { name: 'B', age: 34 },
  { name: 'b', age: 40 },
  { name: 'a', age: 36 }
]

const nameSorter = user => user.name.toLowerCase()
const ageSorter = 'age'

const sortedUsers = _.orderBy(users, [nameSorter, ageSorter], ['desc', 'asc'])