(任一个)是否有可变参数版本? [英] Is there a Variadic Version of either (R.either)?

问题描述

我需要变体版本的 R.two .在网上搜索后，我没有找到解决方案. R.anyPass 可以使用，但是它返回一个布尔值而不是原始值.是否已经有我忽略的解决方案?如果不是，编写可变参数的两个效用函数的最佳方法是什么?

I have a need for a variadic version of R.either. After doing some searching around the web, I have not found a solution. R.anyPass would work but it returns a Boolean instead of the original value. Is there already a solution that I have overlooked? If not, what would be the most optimal way to write a variadic either utility function?

一个例子:

const test = variadicEither(R.multiply(0), R.add(-1), R.add(1), R.add(2))
test(1) // => 2 

推荐答案

您可以结合使用 reduce + reduced :

You could use a combination of reduce + reduced:

const z = (...fns) => x => reduce((res, fn) => res ? reduced(res) : fn(x), false, fns);

console.log(
  z(always(0), always(10), always(2))(11),
  z(always(0), always(''), always(15), always(2))(11),
)

<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.26.1/ramda.min.js"></script>
<script>const {reduce, reduced, always} = R;</script>

(先前尝试)

我会做这样的事情:

const z = unapply(curry((fns, x) => find(applyTo(x), fns)(x)));

console.log(

  z(always(0), always(15), always(2))(10),
  z(always(0), always(''), always(NaN), always(30), always(2))(10),

);

<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.26.1/ramda.min.js"></script>
<script>const {unapply, curry, find, applyTo, always} = R;</script>

这有三个主要警告！

1. 您必须通过两次通过"调用 z ，即 z(... functions)(x)
2. 尽管添加起来应该很容易，但是我并不关心没有函数匹配"的情况.
3. 也许没什么大不了，但是值得注意:一个匹配的谓词将被执行两次

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