# Get the type of a variable as a string

Read the internal [[Class]] tag via Object.prototype.toString.

Canonical: https://1loc.dev/misc/get-type-of-a-variable-in-string/
Version: 1.0.0
Runtime: JavaScript · Node.js 22 / modern browsers
Verification: Local fixtures; no external services
Updated: 2026-10-28

## Implementation

```javascript
function getTypeOf(value) { return Object.prototype.toString.call(value).match(/\[object (.*)\]/)[1]; }
```

## Input

```json
[
  1,
  2
]
```

## Expected output

```json
"Array"
```

## Edge case

Input:
```json
null
```
Output:
```json
"Null"
```

## Limits

- Distinguishes Array, Null, Date and RegExp where typeof says "object". Objects can override the tag with Symbol.toStringTag.

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/get-type-of-a-variable-in-string.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: Curated implementation; explicit input contract, edge case and limits. Original MDX retained as inert source evidence.