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

> jackspeak@4.2.3 ships CommonJS and ESM builds. Dual package — require() works on every Node.js version we test; import works too.

A very strict and proper argument parser.

Last verified Sep 9, 2026 against jackspeak@4.2.3.

jackspeak publishes both a CommonJS entry and a native ESM entry (ESM added in 2.0.0). require("jackspeak") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js 20 || >=22. import "jackspeak" works alongside it.

## What to do

1. Nothing to change. require("jackspeak") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js 20 || >=22. import * as jackspeak from "jackspeak" works alongside it; use named imports for what the ESM entry exports.
2. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 4.2.3 (Feb 7, 2026)
- Module format: Dual (CommonJS + ESM)
- Last CommonJS version: 4.2.3
- Native ESM since: 2.0.0
- TypeScript types: bundled
- Node engines: 20 || >=22
- Weekly downloads: 101.7M
- License: BlueOak-1.0.0

## Runtime test results for jackspeak@4.2.3

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

| Runtime | require("jackspeak") | import "jackspeak" |
|---|---|---|
| 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 jackspeak

ES modules:

```js
import * as jackspeak from "jackspeak";
```

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

CommonJS:

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

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (66 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 2.0.0 – 4.2.3 | Dual (CommonJS + ESM) | Apr 10, 2023 |
| 1.3.0 – 1.4.2 | CommonJS | Feb 1, 2019 |

## Frequently asked

**Is jackspeak ESM-only?**

jackspeak@4.2.3 ships CommonJS and ESM builds. jackspeak publishes both a CommonJS entry and a native ESM entry (ESM added in 2.0.0). require("jackspeak") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js 20 || >=22. import "jackspeak" works alongside it.

**Can I require jackspeak?**

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

**Does jackspeak work in Bun?**

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

**Does jackspeak ship TypeScript types?**

Yes. jackspeak bundles its own type declarations; no @types package is needed.

## Links

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

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