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

> css-tree@3.2.1 ships CommonJS and ESM builds. Dual package — require() works on every Node.js version we test; import works too.

A tool set for CSS: fast detailed parser (CSS → AST), walker (AST traversal), generator (AST → CSS) and lexer (validation and matching) based on specs and browser implementations

Last verified Sep 9, 2026 against css-tree@3.2.1.

css-tree publishes both a CommonJS entry and a native ESM entry (ESM added in 2.0.0). require("css-tree") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js ^10 || ^12.20.0 || ^14.13.0 || >=15.0.0. import "css-tree" works alongside it.

## What to do

1. Nothing to change. require("css-tree") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js ^10 || ^12.20.0 || ^14.13.0 || >=15.0.0. import * as cssTree from "css-tree" works alongside it; use named imports for what the ESM entry exports.
2. TypeScript: npm install -D @types/css-tree

## Facts

- Latest: 3.2.1 (Mar 5, 2026)
- Module format: Dual (CommonJS + ESM)
- Last CommonJS version: 3.2.1
- Native ESM since: 2.0.0
- TypeScript types: @types/css-tree
- Node engines: ^10 || ^12.20.0 || ^14.13.0 || >=15.0.0
- Weekly downloads: 79.6M
- License: MIT

## Runtime test results for css-tree@3.2.1

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

| Runtime | require("css-tree") | import "css-tree" |
|---|---|---|
| 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 css-tree

ES modules:

```js
import * as cssTree from "css-tree";
```

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

CommonJS:

```js
const cssTree = require("css-tree");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (21 versions; the newest 21 shown).

| Versions | Format | First published |
|---|---|---|
| 2.0.0 – 3.2.1 | Dual (CommonJS + ESM) | Dec 3, 2021 |
| 1.0.0 – 1.1.3 | CommonJS | Oct 27, 2020 |

## Frequently asked

**Is css-tree ESM-only?**

css-tree@3.2.1 ships CommonJS and ESM builds. css-tree publishes both a CommonJS entry and a native ESM entry (ESM added in 2.0.0). require("css-tree") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js ^10 || ^12.20.0 || ^14.13.0 || >=15.0.0. import "css-tree" works alongside it.

**Can I require css-tree?**

Yes. css-tree ships a CommonJS entry alongside the native ESM entry. require("css-tree") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js ^10 || ^12.20.0 || ^14.13.0 || >=15.0.0.

**Does css-tree work in Bun?**

Yes. import "css-tree" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does css-tree ship TypeScript types?**

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

## Links

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

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