# Is why-is-node-running ESM-only? Can you require() it?

> why-is-node-running@3.2.2 is ESM-only. ESM-only since 3.0.0 — last CommonJS version is 2.3.0.

Node is running but you don't know why? why-is-node-running is here to help you.

Last verified Sep 9, 2026 against why-is-node-running@3.2.2.

why-is-node-running dropped its CommonJS build in 3.0.0 (July 2024). The last version with a plain require()-able CommonJS entry is 2.3.0, published Jul 8, 2024; it declares support for Node.js >=8.

On Node.js 20.19+, 22.12+ and newer, require("why-is-node-running") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Node.js 18 has no require(esm), and why-is-node-running@3.2.2 declares Node.js >=20.11, so 18 is outside its supported range anyway.

why-is-node-running@3.2.2 declares engines ">=20.11", so Node.js 18 is outside its supported range regardless of module format.

## What to do

1. On Node.js 20.19+, 22.12+ and newer, require("why-is-node-running") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26.
2. From a CommonJS file, use a dynamic import inside an async function: const whyIsNodeRunning = await import("why-is-node-running"). That works on every Node.js version the package supports (>=20.11).
3. If you need a synchronous require() or run Node.js 18: npm install why-is-node-running@2.3.0, the last CommonJS release (published Jul 8, 2024); it declares Node.js >=8.
4. why-is-node-running@3.2.2 declares engines ">=20.11", so Node.js 18 is unsupported regardless: upgrade Node.js or pin an older release.
5. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 3.2.2 (Jan 8, 2025)
- Module format: ESM-only
- Last CommonJS version: 2.3.0
- ESM-only since: 3.0.0 (Jul 8, 2024)
- TypeScript types: bundled
- Node engines: >=20.11
- Weekly downloads: 78.3M
- License: MIT

## Runtime test results for why-is-node-running@3.2.2

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

| Runtime | require("why-is-node-running") | import "why-is-node-running" |
|---|---|---|
| Node.js 18 | fails (ERR_REQUIRE_ESM) | 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 why-is-node-running

ES modules:

```js
import * as whyIsNodeRunning from "why-is-node-running";
```

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

CommonJS:

```js
// Node.js 20.19+, 22.12+ and newer (verified):
const whyIsNodeRunning = require("why-is-node-running");

// Any Node.js version the package supports (>=20.11), from an async function:
async function main() {
  const whyIsNodeRunning = await import("why-is-node-running");
}

// Or pin the last CommonJS release (declares Node.js >=8):
// npm install why-is-node-running@2.3.0
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (24 versions; the newest 24 shown).

| Versions | Format | First published |
|---|---|---|
| 3.0.0 – 3.2.2 | ESM-only | Jul 8, 2024 |
| 1.0.0 – 2.3.0 | CommonJS | Feb 9, 2016 |

## Frequently asked

**Is why-is-node-running ESM-only?**

why-is-node-running@3.2.2 is ESM-only. why-is-node-running dropped its CommonJS build in 3.0.0 (July 2024). The last version with a plain require()-able CommonJS entry is 2.3.0, published Jul 8, 2024; it declares support for Node.js >=8.

**Which version of why-is-node-running still supports CommonJS / require()?**

2.3.0 is the last version of why-is-node-running with a CommonJS build; it declares Node.js >=8. Install it with "npm install why-is-node-running@2.3.0". Every version from 3.0.0 on is ESM-only.

**How do I use why-is-node-running from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const whyIsNodeRunning = await import("why-is-node-running"). That works on every Node.js version the package supports (>=20.11). On Node.js 20.19+, 22.12+ and newer, require("why-is-node-running") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin why-is-node-running@2.3.0 (declares Node.js >=8).

**Does why-is-node-running work in Bun?**

Yes. import "why-is-node-running" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does why-is-node-running ship TypeScript types?**

Yes. why-is-node-running bundles its own type declarations; no @types package is needed.

## Links

- [why-is-node-running on npm](https://www.npmjs.com/package/why-is-node-running)
- [Source repository](https://github.com/mafintosh/why-is-node-running)
- [HTML version](https://canirequire.com/package/why-is-node-running/)
- [JSON version](https://canirequire.com/package/why-is-node-running.json)

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