Merge pull request #1150 from rodmoioliveira/snippets/juxt

add juxt
This commit is contained in:
Angelos Chalaris
2020-05-21 18:53:51 +03:00
committed by GitHub

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snippets/juxt.md Normal file
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---
title: juxt
tags: array,function,advanced
---
Takes several functions as argument and returns a function that is the juxtaposition of those functions.
Use `Array.prototype.map()` to return a `fn` that can take a variable number of `args`.
When `fn` is called, return an array containing the result of applying each `fn` to the `args`.
```js
const juxt = (...fns) => (...args) => [...fns].map(fn => [...args].map(fn));
```
```js
juxt(
x => x + 1,
x => x - 1,
x => x * 10
)(1, 2, 3); // [[2,3,4],[0,1,2],[10,20,30]]
juxt(
s => s.length,
s => s.split(" ").join("-")
)("30 seconds of code"); // [[18],['30-seconds-of-code']]
```