24 lines
690 B
Markdown
24 lines
690 B
Markdown
---
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title: Argument coalescing factory
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tags: function,type
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expertise: intermediate
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cover: blog_images/coffee-phone-tray.jpg
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firstSeen: 2017-12-18T12:15:36+02:00
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lastUpdated: 2020-10-22T20:23:47+03:00
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---
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Customizes a coalesce function that returns the first argument which is `true` based on the given validator.
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- Use `Array.prototype.find()` to return the first argument that returns `true` from the provided argument validation function, `valid`.
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```js
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const coalesceFactory = valid => (...args) => args.find(valid);
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```
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```js
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const customCoalesce = coalesceFactory(
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v => ![null, undefined, '', NaN].includes(v)
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);
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customCoalesce(undefined, null, NaN, '', 'Waldo'); // 'Waldo'
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```
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