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

> cssstyle@6.2.0 is a CommonJS package. CommonJS — require() works on Node.js 20, 22, 24 and 26, fails on 18.

An implementation of the CSSStyleDeclaration class from the CSS Object Model specification

Last verified Sep 9, 2026 against cssstyle@6.2.0.

cssstyle ships CommonJS only. require("cssstyle") works on Node.js 20, 22, 24 and 26 but fails on Node.js 18 (ERR_REQUIRE_ESM). The package declares Node.js >=20. import "cssstyle" 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("cssstyle") works on Node.js 20, 22, 24 and 26 but fails on Node.js 18 (ERR_REQUIRE_ESM). The package declares Node.js >=20.
2. From ES modules use the default import: import cssstyle from "cssstyle"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: npm install -D @types/cssstyle

## Facts

- Latest: 6.2.0 (Mar 2, 2026)
- Module format: CommonJS
- Last CommonJS version: 6.2.0
- TypeScript types: @types/cssstyle
- Node engines: >=20
- Weekly downloads: 58.3M
- License: MIT

## Runtime test results for cssstyle@6.2.0

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

| Runtime | require("cssstyle") | import "cssstyle" |
|---|---|---|
| Node.js 18 | fails (ERR_REQUIRE_ESM) | fails (ERR_REQUIRE_ESM) |
| 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 cssstyle

ES modules:

```js
import cssstyle from "cssstyle";
```

CommonJS:

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

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (76 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 0.2.15 – 6.2.0 | CommonJS | Oct 6, 2014 |

## Frequently asked

**Is cssstyle ESM-only?**

cssstyle@6.2.0 is a CommonJS package. cssstyle ships CommonJS only. require("cssstyle") works on Node.js 20, 22, 24 and 26 but fails on Node.js 18 (ERR_REQUIRE_ESM). The package declares Node.js >=20. import "cssstyle" 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 cssstyle with ES module syntax?**

Yes. import cssstyle from "cssstyle" 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 cssstyle work in Bun?**

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

**Does cssstyle ship TypeScript types?**

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

## Links

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

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