Question

我有这种数据，通常是从api那里获取的，这是我第一次使用lodash。

{
  "_id": "93866",
  "stats": [
    {
      "points": 86,
      "pos": 11,
      "createdAt": "2019-01-16T10:13:40.650Z",
      "updatedAt": "2019-01-16T10:13:40.825Z"
    },
    {
      "points": 79,
      "pos": 26,
      "createdAt": "2019-01-16T10:13:40.650Z",
      "updatedAt": "2019-01-16T10:13:40.825Z"
    },
    {
      "points": 64,
      "pos": 39,
      "createdAt": "2019-01-16T10:13:40.650Z",
      "updatedAt": "2019-01-16T10:13:40.825Z"
    }
  ]
}

我想要做到的就是

[ [ 86, 11 ], [ 79, 26 ], [ 64, 39 ] ]

通过执行此操作，我可以简单地以本机方式执行此操作，

var result = data.stats.map(o => [o.points, o.pos])
// => [ [ 86, 11 ], [ 79, 26 ], [ 64, 39 ] ]

这会产生预期的结果，但是我正在使用的环境取决于lodash的使用。

到目前为止，我已经尝试过_.map(data.stats, 'points')，但是我不确定如何做到[ [ 86, 11 ], [ 79, 26 ], [ 64, 39 ] ]

那怎么办呢？

Answer 1

您可以在函数回调中使用object#destructring。

let data = {"_id":"93866","stats":[{"points":86,"pos":11,"createdAt":"2019-01-16T10:13:40.650Z","updatedAt":"2019-01-16T10:13:40.825Z"},{"points":79,"pos":26,"createdAt":"2019-01-16T10:13:40.650Z","updatedAt":"2019-01-16T10:13:40.825Z"},{"points":64,"pos":39,"createdAt":"2019-01-16T10:13:40.650Z","updatedAt":"2019-01-16T10:13:40.825Z"}]},
    result = _.map(data.stats, ({points, pos}) => [points,pos]);
console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

Answer 2

您可以将lodash的_.at()与_.map()结合使用：

const data = {"_id":"93866","stats":[{"points":86,"pos":11,"createdAt":"2019-01-16T10:13:40.650Z","updatedAt":"2019-01-16T10:13:40.825Z"},{"points":79,"pos":26,"createdAt":"2019-01-16T10:13:40.650Z","updatedAt":"2019-01-16T10:13:40.825Z"},{"points":64,"pos":39,"createdAt":"2019-01-16T10:13:40.650Z","updatedAt":"2019-01-16T10:13:40.825Z"}]};

const result = _.map(data.stats, o => _.at(o, ['points', 'pos']));

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

您还可以使用_.map()和_.at()的{{3}}版来创建函数：

const data = {"_id":"93866","stats":[{"points":86,"pos":11,"createdAt":"2019-01-16T10:13:40.650Z","updatedAt":"2019-01-16T10:13:40.825Z"},{"points":79,"pos":26,"createdAt":"2019-01-16T10:13:40.650Z","updatedAt":"2019-01-16T10:13:40.825Z"},{"points":64,"pos":39,"createdAt":"2019-01-16T10:13:40.650Z","updatedAt":"2019-01-16T10:13:40.825Z"}]};

const fn = _.map(_.at(['points', 'pos']));

const result = fn(data.stats);

console.log(result);

<script src='https://cdn.jsdelivr.net/g/lodash@4(lodash.min.js+lodash.fp.min.js)'></script>

Answer 3

您已经弄清楚了，您只需要结合您的 native 版本和您的lodash尝试：

var result = _.map(data.stats, o => [o.points, o.pos]);

如您所见，我用您的 native 版本中使用的函数将_.map（原为'points'）的第二个参数替换了。

Answer 4

这里是：

_.map(data.stats, obj => [ obj.points, obj.pos ])

编辑：@Hassan Imam使用解构对象做出了一个有趣的答案

嵌套数组中的Lodash映射值

4 个答案: