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

> array-flatten@3.0.0 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Flatten nested arrays

Last verified Sep 9, 2026 against array-flatten@3.0.0.

array-flatten ships CommonJS only. require("array-flatten") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "array-flatten" 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.

It also declares a "module" field, so bundlers such as webpack, Vite and esbuild pick up an ESM build for tree-shaking.

## What to do

1. require("array-flatten") 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 arrayFlatten from "array-flatten"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 3.0.0 (Nov 21, 2019)
- Module format: CommonJS
- Last CommonJS version: 3.0.0
- TypeScript types: bundled
- Node engines: not declared
- Weekly downloads: 40.6M
- License: MIT

## Runtime test results for array-flatten@3.0.0

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

| Runtime | require("array-flatten") | import "array-flatten" |
|---|---|---|
| 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 array-flatten

ES modules:

```js
import arrayFlatten from "array-flatten";
```

CommonJS:

```js
const arrayFlatten = require("array-flatten");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (12 versions; the newest 12 shown).

| Versions | Format | First published |
|---|---|---|
| 0.0.2 – 3.0.0 | CommonJS | Mar 16, 2014 |

## Frequently asked

**Is array-flatten ESM-only?**

array-flatten@3.0.0 is a CommonJS package. array-flatten ships CommonJS only. require("array-flatten") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "array-flatten" 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 array-flatten with ES module syntax?**

Yes. import arrayFlatten from "array-flatten" 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 array-flatten work in Bun?**

Yes. import "array-flatten" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does array-flatten ship TypeScript types?**

Yes. array-flatten bundles its own type declarations; no @types package is needed.

## Links

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

---

For scripts and AI agents: any package is at https://canirequire.com/package/<name>/index.md (Markdown) or https://canirequire.com/package/<name>.json (JSON); the site index is https://canirequire.com/llms.txt. Fetch the URL directly; no search needed.