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

> ast-types@0.16.3 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Esprima-compatible implementation of the Mozilla JS Parser API

Last verified Sep 9, 2026 against ast-types@0.16.3.

ast-types ships CommonJS only. require("ast-types") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=4. import "ast-types" 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("ast-types") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=4.
2. From ES modules use the default import: import astTypes from "ast-types"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 0.16.3 (Aug 30, 2026)
- Module format: CommonJS
- Last CommonJS version: 0.16.3
- TypeScript types: bundled
- Node engines: >=4
- Weekly downloads: 59.8M
- License: MIT

## Runtime test results for ast-types@0.16.3

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

| Runtime | require("ast-types") | import "ast-types" |
|---|---|---|
| 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 ast-types

ES modules:

```js
import astTypes from "ast-types";
```

CommonJS:

```js
const astTypes = require("ast-types");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (174 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 0.8.5 – 0.16.3 | CommonJS | Jul 30, 2015 |

## Frequently asked

**Is ast-types ESM-only?**

ast-types@0.16.3 is a CommonJS package. ast-types ships CommonJS only. require("ast-types") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=4. import "ast-types" 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 ast-types with ES module syntax?**

Yes. import astTypes from "ast-types" 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 ast-types work in Bun?**

Yes. import "ast-types" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does ast-types ship TypeScript types?**

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

## Links

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

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