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javascript - lodash 从对象数组中查找公共值

问题描述

从 Array of Objects 中查找公共值并传送它们

尝试使用 lodash groupBy

var data =[
  {
    "dc": 1,
    "effDate": "1/2/2019",
    "expDate": "1/2/2019",
    "rate": 1,
    "minCharge": 2
  },
  {
    "dc": 1,
    "effDate": "1/2/2019",
    "expDate": "1/2/2019",
    "rate": 2,
    "minCharge": 6
  },
  {
    "dc": 1,
    "effDate": "1/2/2019",
    "expDate": "1/2/2019",
    "rate": 4,
    "minCharge": 7
  }
]

var expectedResult=[
  {
    "dc": 1,
    "effDate": "1/2/2019",
    "expDate": "1/2/2019",
    "rateCharge": [
      {
        "rate": 1,
        "minCharge": 2
      },
      {
        "rate": 2,
        "minCharge": 6
      },
      {
        "rate": 4,
        "minCharge": 7
      }
    ]
  }
]

在数据 dc、effDate、expDate 中是相同的，所以我需要将常见的东西保持为扁平结构并将重复项移动到 rateCharge 中。

var expectedResult=uniqBy(data,(val1.rate,val2.rate) => {
  val1.rate!=val2.rate;    
});

我尝试使用 lodash uniqBy 属性，但没有得到预期的结果。

标签： javascriptecmascript-6lodash

解决方案

您需要按 对项目进行分组effDate，然后使用_.pick()/ _.omit()、将组映射到所需的形式_.map()，并使用_.uniqBy()作为rate唯一标识符。

Typescript 示例（打开浏览器控制台）

const { flow, partialRight: pr, groupBy, map, head, pick, omit, uniqBy } = _

const EFF_DATA = 'effDate'
const baseProps = ['dc', EFF_DATA, 'expDate']

const fn = flow(
  pr(groupBy, EFF_DATA),
  pr(map, g => ({
    ...pick(head(g), baseProps),
    rateCharge: uniqBy(map(g, pr(omit, baseProps)), 'rate')
  }))
)

const data = [{"dc":1,"effDate":"1/2/2019","expDate":"1/2/2019","rate":1,"minCharge":2},{"dc":1,"effDate":"1/2/2019","expDate":"1/2/2019","rate":2,"minCharge":6},{"dc":1,"effDate":"1/2/2019","expDate":"1/2/2019","rate":4,"minCharge":7}]

const result = fn(data)

console.log(result)
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

如果你已经导入了整个 lodash 包，你可以使用链接：

const { flow, partialRight: pr, groupBy, map, head, pick, omit, uniqBy } = _

const EFF_DATA = 'effDate'
const baseProps = ['dc', EFF_DATA, 'expDate']

const data = [{"dc":1,"effDate":"1/2/2019","expDate":"1/2/2019","rate":1,"minCharge":2},{"dc":1,"effDate":"1/2/2019","expDate":"1/2/2019","rate":2,"minCharge":6},{"dc":1,"effDate":"1/2/2019","expDate":"1/2/2019","rate":4,"minCharge":7}]

const result = _(data)
  .groupBy(EFF_DATA)
  .map(g => ({
    ...pick(head(g), baseProps),
    rateCharge: uniqBy(map(g, pr(omit, baseProps)), 'rate')  
  }));

console.log(result)
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

和 lodash/fp 版本：

const { flow, groupBy, map, head, pick, omit, uniqBy, assoc } = _;

const EFF_DATA = 'effDate'
const baseProps = ['dc', EFF_DATA, 'expDate'];

const fn = flow(
  groupBy(EFF_DATA),
  map(g => assoc(
    'rateCharge',
    flow(map(omit(baseProps)), uniqBy('rate'))(g),
    pick(baseProps, head(g))
  ))
)

const data = [{"dc":1,"effDate":"1/2/2019","expDate":"1/2/2019","rate":1,"minCharge":2},{"dc":1,"effDate":"1/2/2019","expDate":"1/2/2019","rate":2,"minCharge":6},{"dc":1,"effDate":"1/2/2019","expDate":"1/2/2019","rate":4,"minCharge":7}]

const result = fn(data)

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

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