22 lines
528 B
Markdown
22 lines
528 B
Markdown
---
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title: Check if array has only one match
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tags: array
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author: chalarangelo
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cover: interior-10
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firstSeen: 2021-07-04T05:00:00-04:00
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---
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Checks if an array has only one value matching the given function.
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- Use `Array.prototype.filter()` in combination with `fn` to find all matching array elements.
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- Use `Array.prototype.length` to check if only one element matches `fn`.
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```js
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const hasOne = (arr, fn) => arr.filter(fn).length === 1;
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```
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```js
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hasOne([1, 2], x => x % 2); // true
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hasOne([1, 3], x => x % 2); // false
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```
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