是否有其他解决方案可以在不插入未更改的键值的情况下使用“R.applySpec”？

Question

是否有其他解决方案可以使用 R.applySpec 而无需插入未更改的键值？（无需在示例中键入 id 和 name 键，因为稍后键将动态更改）。谢谢。

这是我的输入数据

const data = [ 
  [ 
    { id: 'data1', name: 'it is data 1', itemId: 'item1' },
    { id: 'data1', name: 'it is data 1', itemId: 'item2' } 
  ],
  [ 
    { id: 'data2', name: 'it is data 2', itemId: 'item1' } 
  ],
  [ 
    { id: 'data3', name: 'it is data 3', itemId: 'item1' },
    { id: 'data3', name: 'it is data 3', itemId: 'item2' } 
  ] 
]

和输出

[ 
  { 
    id: 'data1', // this one doesn't change
    name: 'it is data 1', // this one doesn't change
    itemId: [ 'item1', 'item2' ] 
  },
  { 
    id: 'data2', // this one doesn't change
    name: 'it is data 2', // this one doesn't change
    itemId: [ 'item1' ] 
  },
  { 
    id: 'data3', // this one doesn't change
    name: 'it is data 3', // this one doesn't change
    itemId: [ 'item1', 'item2' ] 
  } 
]

使用Ramda获取输出的解决方案

const result = R.map(
  R.applySpec({
    id: R.path([0, 'id']),
    name: R.path([0, 'name']), // don't need to type id or name again
    itemId: R.pluck('itemId')
  })
)(data)

Answer 1

我们当然可以像这样在 Ramda 中写一些东西：

const convert = map (lift (mergeRight) (head, pipe (pluck ('itemId'), objOf('itemId')))) 

const data = [[{id: 'data1', name: 'it is data 1', itemId: 'item1'}, {id: 'data1', name: 'it is data 1', itemId: 'item2'}], [{id: 'data2', name: 'it is data 2', itemId: 'item1'}], [{id: 'data3', name: 'it is data 3', itemId: 'item1'}, {id: 'data3', name: 'it is data 3', itemId: 'item2'}]]

console .log (convert (data))

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

<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.27.0/ramda.js"></script>
<script> const {map, lift, mergeRight, head, pipe, pluck, objOf} = R       </script>

不过，我不确定我是否发现它比 ES6/Ramda 版本更易读：

const convert = map (
  reduce ((a, {itemId, ...rest}) => ({...rest, itemId: [...(a .itemId || []), itemId]}), {})
)

或纯 ES6 版本：

const convert = data => data .map (
  ds => ds .reduce (
    (a, {itemId, ...rest}) => ({...rest, itemId: [...(a .itemId || []), itemId]}),
    {}
  )
)

关于 applySpec is interesting. This function lets you build a new object out of the old one, but you have to entirely describe the new object. There is another function, evolve 的问题，它保持输入对象的所有属性不变，仅替换那些特别提到的，通过将函数应用于它们的当前值。但是 evolve 中函数的输入只接受当前值，不像 applySpec 可以访问整个原始对象。

我可以看到结合这些行为的功能的一些基本原理。但是对于它应该如何工作，我的脑子里并没有一个清晰的 API。如果你对此有一些想法，想要提出建议，Ramda团队永远是looking for suggestions.

是否有其他解决方案可以在不插入未更改的键值的情况下使用“R.applySpec”？

Is there other solution to use `R.applySpec` without inserting the unchanged keys value?

arrays

ramda.js