# Swap two variables

Exchange two values with array destructuring.

Canonical: https://1loc.dev/misc/swap-two-variables/
Version: 1.0.0
Runtime: JavaScript · Node.js 22 / modern browsers
Verification: Local fixtures; no external services
Updated: 2026-10-28

## Implementation

```javascript
function swap([a, b]) { [a, b] = [b, a]; return [a, b]; }
```

## Input

```json
[
  "ana@example.com",
  "rui@example.com"
]
```

## Expected output

```json
[
  "rui@example.com",
  "ana@example.com"
]
```

## Edge case

Input:
```json
[
  0,
  null
]
```
Output:
```json
[
  null,
  0
]
```

## Limits

- Destructuring works for any values. The original’s arithmetic tricks (a = b + ((b = a), 0)) only work for numbers and are harder to read.

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/swap-two-variables.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: Wraps the destructuring swap in a function so it can run; the arithmetic variants are not included. Original MDX retained as inert source evidence.