# Cast a value as an array

Wrap a single value in an array and return arrays unchanged.

Canonical: https://1loc.dev/array/cast-a-value-as-an-array/
Version: 1.0.0
Runtime: JavaScript · Node.js 22 / modern browsers
Verification: Local fixtures; no external services
Updated: 2026-10-28

## Implementation

```javascript
function castArray(value) { return Array.isArray(value) ? value : [value]; }
```

## Input

```json
"ana@example.com"
```

## Expected output

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

## Edge case

Input:
```json
[]
```
Output:
```json
[]
```

## Limits

- Arrays are returned as they are, not copied.
- Useful for a field that accepts one value or many, such as a list of recipients, before iterating over it.

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/cast-a-value-as-an-array.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: Original implementation kept; explicit contract and edge case. Original MDX retained as inert source evidence.