数组分组项和计数项的简洁方法

我有一个像这样的数组:

const arr = [ {name: 'Server 1', country: 'DE'}, {name: 'Server 2', country: 'PL'}, 
              {name: 'Server 3', country: 'US'}, {name: 'Server 4', country: 'DE'}, 
              {name: 'Server 5', country: 'US'}];

我想要的是 group and count 以获得如下的输出:

What I want is group and count to get the ouput like below:

 [
  {
    "country": "DE",
    "count": 2
  },
  {
    "country": "PL",
    "count": 1
  },
  {
    "country": "US",
    "count": 2
  }
]

当前，我正在使用 lodash ，但是我认为有更好的方法(例如，使用 _groupBy 或类似的方法)来解决它，对吧?

Currently, I'm using lodash but I think there are better ways (for example, using _groupBy or something like that) to resolve it, right?

我的代码在这里:

const arr = [ {name: 'Server 1', country: 'DE'}, {name: 'Server 2', country: 'PL'}, {name: 'Server 3', country: 'US'}, {name: 'Server 4', country: 'DE'}, {name: 'Server 5', country: 'US'}];

const objectGroupby = _.countBy(arr, 'country');
const result = Object.entries(objectGroupby).map(([key, value]) => ({country: key, count: value}));
console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js"></script>

如您所见， _.countBy(arr，'country')只是返回一个对象而不是数组.

As you can see, _.countBy(arr, 'country') just returns an object instead of an array.

{
  "DE": 2,
  "PL": 1,
  "US": 2
}

然后我必须使用 Object.entries()& map 来解决它.

Then I have to use Object.entries() & map to resolve it.