27 lines
648 B
Markdown
27 lines
648 B
Markdown
---
|
|
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']]
|
|
```
|