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