# Is rollup-plugin-filesize ESM-only? Can you require() it?

> rollup-plugin-filesize@10.0.0 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

A rollup plugin to show filesize in the cli

Last verified Sep 9, 2026 against rollup-plugin-filesize@10.0.0.

rollup-plugin-filesize ships CommonJS only. require("rollup-plugin-filesize") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=16.0.0. import "rollup-plugin-filesize" 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.

It also declares a "module" field, so bundlers such as webpack, Vite and esbuild pick up an ESM build for tree-shaking.

## What to do

1. require("rollup-plugin-filesize") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=16.0.0.
2. From ES modules use the default import: import rollupPluginFilesize from "rollup-plugin-filesize"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 10.0.0 (Feb 27, 2023)
- Module format: CommonJS
- Last CommonJS version: 10.0.0
- TypeScript types: bundled
- Node engines: >=16.0.0
- Weekly downloads: 70K
- License: MIT

## Runtime test results for rollup-plugin-filesize@10.0.0

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

| Runtime | require("rollup-plugin-filesize") | import "rollup-plugin-filesize" |
|---|---|---|
| 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 rollup-plugin-filesize

ES modules:

```js
import rollupPluginFilesize from "rollup-plugin-filesize";
```

CommonJS:

```js
const rollupPluginFilesize = require("rollup-plugin-filesize");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (43 versions; the newest 43 shown).

| Versions | Format | First published |
|---|---|---|
| 0.1.0 – 10.0.0 | CommonJS | Jan 27, 2016 |

## Frequently asked

**Is rollup-plugin-filesize ESM-only?**

rollup-plugin-filesize@10.0.0 is a CommonJS package. rollup-plugin-filesize ships CommonJS only. require("rollup-plugin-filesize") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=16.0.0. import "rollup-plugin-filesize" 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 rollup-plugin-filesize with ES module syntax?**

Yes. import rollupPluginFilesize from "rollup-plugin-filesize" 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 rollup-plugin-filesize work in Bun?**

Yes. import "rollup-plugin-filesize" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does rollup-plugin-filesize ship TypeScript types?**

Yes. rollup-plugin-filesize bundles its own type declarations; no @types package is needed.

## Links

- [rollup-plugin-filesize on npm](https://www.npmjs.com/package/rollup-plugin-filesize)
- [Source repository](https://github.com/ritz078/rollup-plugin-filesize)
- [HTML version](https://canirequire.com/package/rollup-plugin-filesize/)
- [JSON version](https://canirequire.com/package/rollup-plugin-filesize.json)

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