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

> async-function@1.0.0 ships CommonJS and ESM builds. Dual package — require() works on every Node.js version we test; import works too.

A function that returns the normally hidden `AsyncFunction` constructor

Last verified Sep 9, 2026 against async-function@1.0.0.

async-function publishes both a CommonJS entry and a native ESM entry (ESM added in 1.0.0). require("async-function") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.4. import "async-function" works alongside it.

## What to do

1. Nothing to change. require("async-function") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.4. import * as asyncFunction from "async-function" works alongside it; use named imports for what the ESM entry exports.
2. TypeScript: no types are available for async-function; declare the module yourself if you need them.

## Facts

- Latest: 1.0.0 (Jan 23, 2025)
- Module format: Dual (CommonJS + ESM)
- Last CommonJS version: 1.0.0
- Native ESM since: 1.0.0
- TypeScript types: none
- Node engines: >= 0.4
- Weekly downloads: 25.6M
- License: MIT

## Runtime test results for async-function@1.0.0

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

| Runtime | require("async-function") | import "async-function" |
|---|---|---|
| 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 async-function

ES modules:

```js
import * as asyncFunction from "async-function";
```

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

CommonJS:

```js
const asyncFunction = require("async-function");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (2 versions; the newest 2 shown).

| Versions | Format | First published |
|---|---|---|
| 1.0.0 | Dual (CommonJS + ESM) | Jan 23, 2025 |
| 0.1.0 | CommonJS | Sep 15, 2016 |

## Frequently asked

**Is async-function ESM-only?**

async-function@1.0.0 ships CommonJS and ESM builds. async-function publishes both a CommonJS entry and a native ESM entry (ESM added in 1.0.0). require("async-function") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.4. import "async-function" works alongside it.

**Can I require async-function?**

Yes. async-function ships a CommonJS entry alongside the native ESM entry. require("async-function") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.4.

**Does async-function work in Bun?**

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

**Does async-function ship TypeScript types?**

No. async-function ships no type declarations and there is no @types package for it.

## Links

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

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