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

> on-finished@2.4.1 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Execute a callback when a request closes, finishes, or errors

Last verified Sep 9, 2026 against on-finished@2.4.1.

on-finished ships CommonJS only. require("on-finished") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.8. import "on-finished" 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("on-finished") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.8.
2. From ES modules use the default import: import onFinished from "on-finished"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: npm install -D @types/on-finished

## Facts

- Latest: 2.4.1 (Feb 22, 2022)
- Module format: CommonJS
- Last CommonJS version: 2.4.1
- TypeScript types: @types/on-finished
- Node engines: >= 0.8
- Weekly downloads: 96.7M
- License: MIT

## Runtime test results for on-finished@2.4.1

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

| Runtime | require("on-finished") | import "on-finished" |
|---|---|---|
| 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 on-finished

ES modules:

```js
import onFinished from "on-finished";
```

CommonJS:

```js
const onFinished = require("on-finished");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (8 versions; the newest 8 shown).

| Versions | Format | First published |
|---|---|---|
| 2.0.0 – 2.4.1 | CommonJS | Aug 16, 2014 |

## Frequently asked

**Is on-finished ESM-only?**

on-finished@2.4.1 is a CommonJS package. on-finished ships CommonJS only. require("on-finished") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.8. import "on-finished" 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 on-finished with ES module syntax?**

Yes. import onFinished from "on-finished" 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 on-finished work in Bun?**

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

**Does on-finished ship TypeScript types?**

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

## Links

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

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