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

> jest-worker@30.5.1 ships CommonJS and ESM builds. Dual package — require() works on every Node.js version we test; import works too.

Module for executing heavy tasks under forked processes in parallel, by providing a `Promise` based interface, minimum overhead, and bound workers.

Last verified Sep 9, 2026 against jest-worker@30.5.1.

jest-worker publishes both a CommonJS entry and a native ESM entry (ESM added in 30.0.0). require("jest-worker") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js ^18.14.0 || ^20.0.0 || ^22.0.0 || >=24.0.0. import "jest-worker" works alongside it.

## What to do

1. Nothing to change. require("jest-worker") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js ^18.14.0 || ^20.0.0 || ^22.0.0 || >=24.0.0. import * as jestWorker from "jest-worker" works alongside it; use named imports for what the ESM entry exports.
2. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 30.5.1 (Sep 1, 2026)
- Module format: Dual (CommonJS + ESM)
- Last CommonJS version: 30.5.1
- Native ESM since: 30.0.0
- TypeScript types: bundled
- Node engines: ^18.14.0 || ^20.0.0 || ^22.0.0 || >=24.0.0
- Weekly downloads: 107.5M
- License: MIT

## Runtime test results for jest-worker@30.5.1

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

| Runtime | require("jest-worker") | import "jest-worker" |
|---|---|---|
| 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 jest-worker

ES modules:

```js
import * as jestWorker from "jest-worker";
```

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

CommonJS:

```js
const jestWorker = require("jest-worker");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (94 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 30.0.0 – 30.5.1 | Dual (CommonJS + ESM) | Jun 10, 2025 |
| 26.6.2 – 29.7.0 | CommonJS | Nov 2, 2020 |

## Frequently asked

**Is jest-worker ESM-only?**

jest-worker@30.5.1 ships CommonJS and ESM builds. jest-worker publishes both a CommonJS entry and a native ESM entry (ESM added in 30.0.0). require("jest-worker") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js ^18.14.0 || ^20.0.0 || ^22.0.0 || >=24.0.0. import "jest-worker" works alongside it.

**Can I require jest-worker?**

Yes. jest-worker ships a CommonJS entry alongside the native ESM entry. require("jest-worker") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js ^18.14.0 || ^20.0.0 || ^22.0.0 || >=24.0.0.

**Does jest-worker work in Bun?**

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

**Does jest-worker ship TypeScript types?**

Yes. jest-worker bundles its own type declarations; no @types package is needed.

## Links

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

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