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

> acorn@8.18.0 ships CommonJS and ESM builds. Dual package — require() works on every Node.js version we test; import works too.

ECMAScript parser

Last verified Sep 9, 2026 against acorn@8.18.0.

acorn publishes both a CommonJS entry and a native ESM entry (ESM added in 8.0.0). require("acorn") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=0.4.0. import "acorn" works alongside it.

## What to do

1. Nothing to change. require("acorn") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=0.4.0. import * as acorn from "acorn" works alongside it; use named imports for what the ESM entry exports.
2. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 8.18.0 (Jul 28, 2026)
- Module format: Dual (CommonJS + ESM)
- Last CommonJS version: 8.18.0
- Native ESM since: 8.0.0
- TypeScript types: bundled
- Node engines: >=0.4.0
- Weekly downloads: 221.9M
- License: MIT

## Runtime test results for acorn@8.18.0

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

| Runtime | require("acorn") | import "acorn" |
|---|---|---|
| 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 acorn

ES modules:

```js
import * as acorn from "acorn";
```

Namespace import shown because the ESM entry may have no default export; use named imports for what it exports.

CommonJS:

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

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (140 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 8.0.0 – 8.18.0 | Dual (CommonJS + ESM) | Aug 12, 2020 |
| 6.0.2 – 7.4.1 | CommonJS | Sep 26, 2018 |

## Frequently asked

**Is acorn ESM-only?**

acorn@8.18.0 ships CommonJS and ESM builds. acorn publishes both a CommonJS entry and a native ESM entry (ESM added in 8.0.0). require("acorn") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=0.4.0. import "acorn" works alongside it.

**Can I require acorn?**

Yes. acorn ships a CommonJS entry alongside the native ESM entry. require("acorn") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=0.4.0.

**Does acorn work in Bun?**

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

**Does acorn ship TypeScript types?**

Yes. acorn bundles its own type declarations; no @types package is needed.

## Links

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