使用 ramda 计算嵌套对象数组中的成员

Question

[
    {
        'members': {
            'infants': [{ 'name': 'A' }],
            'adults': [{ 'name': 'B' }, { 'name': 'C' }],
            'children': [{ 'name': 'D' }],
        },
    },
    {
        'members': {
            'infants': [],
            'adults': [{ 'name': 'F' }, { 'name': 'G' }, { 'name': 'H' }],
            'children': [],
        },
    },
]

这是我的数据对象的样子

我试着像这样实现它

const travelerCounter = compose(
  length,
  unnest,
  unnest,
  map(values),
  unnest,
  pluck('members')
)

我不确定这是否是一个好的解决方案，或者我们可以用紧凑的方式编写它。 它还显示了正确的数字，但如果我尝试在 TypeScript 中使用它，我会出现 TS 错误 ts(2769)

Answer 1

您可以将R.chain与R.values一起使用，然后展平为单个数组：

 const { compose, length, flatten, chain, values, pluck } = R const fn = compose( length, // get the length flatten, // flatten to a single array chain(values), // combine the values of all member objects pluck('members') // get members objects ) const data = [{"members":{"infants":[{"name":"A"}],"adults":[{"name":"B"},{"name":"C"}],"children":[{"name":"D"}]}},{"members":{"infants":[],"adults":[{"name":"F"},{"name":"G"},{"name":"H"}],"children":[]}}] const result = fn(data) console.log(result)

 <script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.28.0/ramda.min.js" integrity="sha512-t0vPcE8ynwIFovsylwUuLPIbdhDj6fav2prN9fEu/VYBupsmrmk9x43Hvnt+Mgn2h5YPSJOk7PMo9zIeGedD1A==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

TS 类型：

type Members = { members: Record<string, { name: string }[]> };

const fn: (v: Members[]) => number = compose(
  length, // get the length
  flatten, // flatten to a single array
  chain(values), // combine the values of all member objects
  pluck("members") // get members objects
);

除了展平，您还可以提取长度，然后对它们求和：

 const { compose, sum, pluck, length, chain, values } = R const fn = compose( sum, // sum the lengths pluck('length'), // get the length of each members array chain(values), // combine values of all members objects pluck('members') // get members objects ) const data = [{"members":{"infants":[{"name":"A"}],"adults":[{"name":"B"},{"name":"C"}],"children":[{"name":"D"}]}},{"members":{"infants":[],"adults":[{"name":"F"},{"name":"G"},{"name":"H"}],"children":[]}}] const result = fn(data) console.log(result)

 <script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.28.0/ramda.min.js" integrity="sha512-t0vPcE8ynwIFovsylwUuLPIbdhDj6fav2prN9fEu/VYBupsmrmk9x43Hvnt+Mgn2h5YPSJOk7PMo9zIeGedD1A==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

TS 类型——在这种情况下，TS 无法推断出 R.compose 中的类型，因此我们需要提供更详细的签名：

type Member = { name: string };
type MembersRecords = Record<string, Member[]>;
type Members = { members: MembersRecords };

const fn = compose<[Members[]], MembersRecords[], Member[][], number[], number>(
  sum, // sum the lengths
  pluck('length'), // get the length of each members array
  chain(values), // combine values of all members objects
  pluck('members') // get members objects
)