29 lines
743 B
Markdown
29 lines
743 B
Markdown
---
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title: juxt
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tags: array,function,advanced
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---
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Takes several functions as argument and returns a fn that is the juxtaposition of those fns.
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juxt(fn1, fn2, fn3, ...) use `Array.prototype.map()` to return a `func` that can take a variable number of `args`.
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When `func` is called, return a array containing the result of applying each fn (fn1, fn2, fn3, ...) to the `args`.
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```js
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const juxt = (...fns) => (...x) => [...fns].map(fn => [...x].map(x => fn(x)));
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```
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```js
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juxt(
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x => x + 1,
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x => x - 1,
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x => x * 10,
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x => x / 10
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)(1, 2, 3) // => [ [ 2, 3, 4 ], [ 0, 1, 2 ], [ 10, 20, 30 ], [ 0.1, 0.2, 0.3 ] ]
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juxt(
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s => s.length,
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s => s.split(" ").join("-")
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)("30 seconds of code") // => [ [ 18 ], [ '30-seconds-of-code' ] ]
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```
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