# Sort an array of dates

Sort dates ascending or descending without changing the input.

Canonical: https://1loc.dev/date-time/sort-an-array-of-dates/
Version: 1.0.0
Runtime: JavaScript · Node.js 22 / modern browsers
Verification: Local fixtures; no external services
Updated: 2026-10-28

## Implementation

```javascript
function sortDates({ dates, order = 'asc' }) { const sorted = [...dates].sort((a, b) => Date.parse(a) - Date.parse(b)); return order === 'desc' ? sorted.reverse() : sorted; }
```

## Input

```json
{
  "dates": [
    "2026-10-28",
    "2026-01-01",
    "2026-05-05"
  ]
}
```

## Expected output

```json
[
  "2026-01-01",
  "2026-05-05",
  "2026-10-28"
]
```

## Edge case

Input:
```json
{
  "dates": [
    "2026-01-01",
    "2026-10-28"
  ],
  "order": "desc"
}
```
Output:
```json
[
  "2026-10-28",
  "2026-01-01"
]
```

## Limits

- The original descending comparator returned a boolean, which sort treats inconsistently; a numeric difference is required. It also sorted in place.

The lab validates types and size before calling this function. Add equivalent validation at your own trust boundary.

## Source and license

Original: https://github.com/phuocng/1loc/blob/14b481cf60dff1620ab1bb99a43b1f68068cdd9b/contents/sort-an-array-of-dates.mdx
Author: Nguyen Huu Phuoc and original contributors
Contributors: See original repository history
Source commit: 14b481cf60dff1620ab1bb99a43b1f68068cdd9b
Copyright (c) 2020 phuoc-ng
License: MIT — https://1loc.dev/licenses/
Maintainer: Oveyon
Modifications: Uses a numeric comparator on a copy; the original descending comparator returned a boolean and sorted in place. Original MDX retained as inert source evidence.