---
title: Initialize array with reversed range
type: snippet
language: javascript
tags: [array]
cover: interior-4
excerpt: Initializes an inclusive array with numbers in a range, reversed, using a common `step` difference.
dateModified: 2020-10-20T23:02:01+03:00
---

Initializes an array containing the numbers in the specified range (in reverse) where `start` and `end` are inclusive with their common difference `step`.

- Use `Array.from()` to create an array of the desired length, `(end - start + 1) / step`.
- Use `Array.prototype.map()` to fill the array with the desired values in the given range.
- Omit the second argument, `start`, to use a default value of `0`.
- Omit the last argument, `step`, to use a default value of `1`.

```js
const initializeArrayWithRangeRight = (end, start = 0, step = 1) =>
  Array.from({ length: Math.ceil((end + 1 - start) / step) }).map(
    (v, i, arr) => (arr.length - i - 1) * step + start
  );
```

```js
initializeArrayWithRangeRight(5); // [5, 4, 3, 2, 1, 0]
initializeArrayWithRangeRight(7, 3); // [7, 6, 5, 4, 3]
initializeArrayWithRangeRight(9, 0, 2); // [8, 6, 4, 2, 0]
```