# Is isarray ESM-only? Can you require() it?

> isarray@2.0.5 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Array#isArray for older browsers

Last verified Sep 9, 2026 against isarray@2.0.5.

isarray ships CommonJS only. require("isarray") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "isarray" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

## What to do

1. require("isarray") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun.
2. From ES modules use the default import: import isarray from "isarray"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: npm install -D @types/isarray

## Facts

- Latest: 2.0.5 (Jul 8, 2019)
- Module format: CommonJS
- Last CommonJS version: 2.0.5
- TypeScript types: @types/isarray
- Node engines: not declared
- Weekly downloads: 174.9M
- License: MIT

## Runtime test results for isarray@2.0.5

Installed and executed on Sep 9, 2026 with require("isarray") from a CommonJS file and import "isarray" from an ES module.

| Runtime | require("isarray") | import "isarray" |
|---|---|---|
| Node.js 18 | works | works |
| Node.js 20 | works | works |
| Node.js 22 | works | works |
| Node.js 24 | works | works |
| Node.js 26 | works | works |
| Bun 1.4.0 | works | works |

## How to import isarray

ES modules:

```js
import isarray from "isarray";
```

CommonJS:

```js
const isarray = require("isarray");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (9 versions; the newest 9 shown).

| Versions | Format | First published |
|---|---|---|
| 0.0.0 – 2.0.5 | CommonJS | May 22, 2013 |

## Frequently asked

**Is isarray ESM-only?**

isarray@2.0.5 is a CommonJS package. isarray ships CommonJS only. require("isarray") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "isarray" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

**Can I import isarray with ES module syntax?**

Yes. import isarray from "isarray" works in Node.js and Bun because they support importing CommonJS modules. Named imports work only when Node.js can statically detect the exports.

**Does isarray work in Bun?**

Yes. import "isarray" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does isarray ship TypeScript types?**

Not bundled. Install the community types with "npm install -D @types/isarray".

## Links

- [isarray on npm](https://www.npmjs.com/package/isarray)
- [Source repository](https://github.com/juliangruber/isarray)
- [HTML version](https://canirequire.com/package/isarray/)
- [JSON version](https://canirequire.com/package/isarray.json)

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