24 lines
770 B
Markdown
24 lines
770 B
Markdown
---
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title: reduceWhich
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tags: array,intermediate
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---
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Returns the minimum/maximum value of an array, after applying the provided function to set comparing rule.
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- Use `Array.prototype.reduce()` in combination with the `comparator` function to get the appropriate element in the array.
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- You can omit the second parameter, `comparator`, to use the default one that returns the minimum element in the array.
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```js
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const reduceWhich = (arr, comparator = (a, b) => a - b) =>
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arr.reduce((a, b) => (comparator(a, b) >= 0 ? b : a));
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```
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```js
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reduceWhich([1, 3, 2]); // 1
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reduceWhich([1, 3, 2], (a, b) => b - a); // 3
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reduceWhich(
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[{ name: 'Tom', age: 12 }, { name: 'Jack', age: 18 }, { name: 'Lucy', age: 9 }],
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(a, b) => a.age - b.age
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); // {name: 'Lucy', age: 9}
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```
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