28 lines
726 B
Markdown
28 lines
726 B
Markdown
---
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title: juxt
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tags: function,advanced
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firstSeen: 2020-05-20T19:58:39+03:00
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lastUpdated: 2020-10-20T23:29:39+03:00
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---
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Takes several functions as argument and returns a function that is the juxtaposition of those functions.
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- Use `Array.prototype.map()` to return a `fn` that can take a variable number of `args`.
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- When `fn` is called, return an array containing the result of applying each `fn` to the `args`.
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```js
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const juxt = (...fns) => (...args) => [...fns].map(fn => [...args].map(fn));
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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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)(1, 2, 3); // [[2, 3, 4], [0, 1, 2], [10, 20, 30]]
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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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