22 lines
623 B
Markdown
22 lines
623 B
Markdown
---
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title: sortedIndex
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tags: array,math,intermediate
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---
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Returns the lowest index at which value should be inserted into array in order to maintain its sort order.
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Check if the array is sorted in descending order (loosely).
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Use `Array.prototype.findIndex()` to find the appropriate index where the element should be inserted.
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```js
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const sortedIndex = (arr, n) => {
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const isDescending = arr[0] > arr[arr.length - 1];
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const index = arr.findIndex(el => (isDescending ? n >= el : n <= el));
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return index === -1 ? arr.length : index;
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};
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```
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```js
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sortedIndex([5, 3, 2, 1], 4); // 1
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sortedIndex([30, 50], 40); // 1
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``` |