javascript - Lodash:将具有重复值的数组转换为具有重复出现次数的对象

Question

这是我的数组:

['California','Texas','Texas','Texas','New York','Missouri','New Mexico','California']

lodash 中有没有一种方法可以将其转换为具有重复出现次数的对象，如下所示:

[
    {'name':'California', 'count':2},
    {'name':'Texas', 'count':3},
    {'name':'New York', 'count':1},
    {'name':'Missouri', 'count':1},
    {'name':'New Mexico', 'count':1},
]

我尝试了很多组合，但都没有成功。文档:https://lodash.com/docs#countBy

Answer 1

您可以只映射 _.countBy 的结果。

var array = ['California','Texas','Texas','Texas','New York','Missouri','New Mexico','California'],
    count = _.countBy(array),
    result = _.map(count, (v, k) => ({ name: k, count: v }));

console.log(count);
console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.15.0/lodash.min.js"></script>

结合_.chain

var array = ['California','Texas','Texas','Texas','New York','Missouri','New Mexico','California'],
    count = _
        .chain(array)
        .countBy()
        .map((v, k) => ({ name: k, count: v }));

console.log(count);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.15.0/lodash.min.js"></script>