# Is optimize-css-assets-webpack-plugin ESM-only? Can you require() it?

> optimize-css-assets-webpack-plugin@6.0.1 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

A Webpack plugin to optimize \ minimize CSS assets.

Last verified Sep 9, 2026 against optimize-css-assets-webpack-plugin@6.0.1.

optimize-css-assets-webpack-plugin ships CommonJS only. require("optimize-css-assets-webpack-plugin") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "optimize-css-assets-webpack-plugin" 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("optimize-css-assets-webpack-plugin") 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 optimizeCssAssetsWebpackPlugin from "optimize-css-assets-webpack-plugin"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: npm install -D @types/optimize-css-assets-webpack-plugin

## Facts

- Latest: 6.0.1 (Jun 23, 2021)
- Module format: CommonJS
- Last CommonJS version: 6.0.1
- TypeScript types: @types/optimize-css-assets-webpack-plugin
- Node engines: not declared
- Weekly downloads: 1.0M
- License: MIT

## Runtime test results for optimize-css-assets-webpack-plugin@6.0.1

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

| Runtime | require("optimize-css-assets-webpack-plugin") | import "optimize-css-assets-webpack-plugin" |
|---|---|---|
| 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 optimize-css-assets-webpack-plugin

ES modules:

```js
import optimizeCssAssetsWebpackPlugin from "optimize-css-assets-webpack-plugin";
```

CommonJS:

```js
const optimizeCssAssetsWebpackPlugin = require("optimize-css-assets-webpack-plugin");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (27 versions; the newest 27 shown).

| Versions | Format | First published |
|---|---|---|
| 1.0.0 – 6.0.1 | CommonJS | Jan 9, 2016 |

## Frequently asked

**Is optimize-css-assets-webpack-plugin ESM-only?**

optimize-css-assets-webpack-plugin@6.0.1 is a CommonJS package. optimize-css-assets-webpack-plugin ships CommonJS only. require("optimize-css-assets-webpack-plugin") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "optimize-css-assets-webpack-plugin" 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 optimize-css-assets-webpack-plugin with ES module syntax?**

Yes. import optimizeCssAssetsWebpackPlugin from "optimize-css-assets-webpack-plugin" 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 optimize-css-assets-webpack-plugin work in Bun?**

Yes. import "optimize-css-assets-webpack-plugin" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does optimize-css-assets-webpack-plugin ship TypeScript types?**

Not bundled. Install the community types with "npm install -D @types/optimize-css-assets-webpack-plugin".

## Links

- [optimize-css-assets-webpack-plugin on npm](https://www.npmjs.com/package/optimize-css-assets-webpack-plugin)
- [Source repository](https://github.com/NMFR/optimize-css-assets-webpack-plugin)
- [HTML version](https://canirequire.com/package/optimize-css-assets-webpack-plugin/)
- [JSON version](https://canirequire.com/package/optimize-css-assets-webpack-plugin.json)

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