javascript - 使用 lodash 进行分组和分层映射

Question

我正在尝试使用 Lodash 转换一些数据分组和映射。这是示例数据:

var data = [
{name: 'x', qty: 0, rate: 10},
{name: 'x', qty: 10, rate: 2},
{name: 'y', qty: 5, rate: 20},
{name: 'y', qty: 55, rate: 11}]

我需要以下格式的数据:

var data = [
{name: 'x', pricing: [{qty: 0, rate: 10}, {qty: 10, rate: 2}]},
{name: 'y', pricing: [{qty: 5, rate: 20}, {qty: 55, rate: 11}]}]

以下是我的尝试:

var m = _.chain(data)
.groupBy(data, 'name')
.map( function(i) {
  return {
    name: _.first(i).name,
    pricing: _.map(i, function(r) {
      return _.pick(r, ['qty', 'rate'])
    })
  }
})

这产生

[{
    "name": "x",
    "pricing": [
      {"qty": 0, "rate": 10},
      {"qty": 10, "rate": 2},
      {"qty": 5,"rate": 20},
      {"qty": 55,"rate": 11}]
}]

我一直无法弄清楚我做错了什么。也许这甚至都无效，还有更好的方法吗？

Answer 1

您需要映射新对象并​​获取选取的值。

var data = [{ name: 'x', qty: 0, rate: 10 }, { name: 'x', qty: 10, rate: 2 }, { name: 'y', qty: 5, rate: 20 }, { name: 'y', qty: 55, rate: 11 }],
    result = _(data)
        .groupBy('name')
        .map((pricing, name) => ({
            name,
            pricing: _.map(pricing, _.partialRight(_.pick, ['qty', 'rate']))
        }))
        .value();

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

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