Javascript Lodash：如何使用 orderBy 对集合进行不区分大小写的排序？
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Lodash : how to do a case insensitive sorting on a collection using orderBy?
提问by WhiteEleven
I checked this answerbut to achieve the same result, that is to get case-insensitive sorting, I need to use orderByinstead of sortBysince it gives the ability to specify the sort order.
我检查了这个答案，但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因为它提供了指定排序顺序的能力。
The only way I found to achieve it was to create a cloned "middle" array mapped to lower case the name:
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);
This seems really expensive and it will even be more complex with multiple sortings and dynamic properties names.
这看起来真的很昂贵，而且如果有多个排序和动态属性名称，它甚至会更加复杂。
Is there a better idea ?
有更好的主意吗？
Here is a Plunker : https://plnkr.co/edit/i1ywyxjFctuNfHtPTcgG
这是一个 Plunker：https://plnkr.co/edit/i1ywyxjFctuNfHtPTcgG
回答by Felix Kling
The documentationspecifies that you can pass a function as "iteratee":
该文档指定您可以将函数作为“iteratee”传递：
[iteratees=[_.identity]] (Array[]|Function[]|Object[]|string[]): The iteratees to sort by.
[iteratees=[_.identity]] (Array[]|Function[]|Object[]|string[])：要排序的迭代对象。
So you can do
所以你可以做
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>回答by MaxineHu
Ordering by multiple properties:
按多个属性排序：
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'])
回答by Agustí Sánchez
You can combine Felix Kling example with _.get function to sort by dynamic nested attributes:
您可以将 Felix Kling 示例与 _.get 函数结合使用，以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()]);
