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

> path-key@4.0.0 is ESM-only. ESM-only since 4.0.0 — last CommonJS version is 3.1.1.

Get the PATH environment variable key cross-platform

Last verified Sep 9, 2026 against path-key@4.0.0.

path-key dropped its CommonJS build in 4.0.0 (April 2021). The last version with a plain require()-able CommonJS entry is 3.1.1, published Nov 22, 2019; it declares support for Node.js >=8.

On Node.js 20.19+, 22.12+ and newer, require("path-key") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. On Node.js 18, which has no require(esm), require("path-key") fails with ERR_REQUIRE_ESM.

## What to do

1. On Node.js 20.19+, 22.12+ and newer, require("path-key") 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 pathKey = await import("path-key"). That works on every Node.js version the package supports (>=12).
3. If you need a synchronous require() or run Node.js 18: npm install path-key@3.1.1, the last CommonJS release (published Nov 22, 2019); it declares Node.js >=8.
4. TypeScript: npm install -D @types/path-key

## Facts

- Latest: 4.0.0 (Apr 9, 2021)
- Module format: ESM-only
- Last CommonJS version: 3.1.1
- ESM-only since: 4.0.0 (Apr 9, 2021)
- TypeScript types: @types/path-key
- Node engines: >=12
- Weekly downloads: 244.9M
- License: MIT

## Runtime test results for path-key@4.0.0

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

| Runtime | require("path-key") | import "path-key" |
|---|---|---|
| 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 path-key

ES modules:

```js
import * as pathKey from "path-key";
```

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 pathKey = require("path-key");

// Any Node.js version the package supports (>=12), from an async function:
async function main() {
  const pathKey = await import("path-key");
}

// Or pin the last CommonJS release (declares Node.js >=8):
// npm install path-key@3.1.1
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (7 versions; the newest 7 shown).

| Versions | Format | First published |
|---|---|---|
| 4.0.0 | ESM-only | Apr 9, 2021 |
| 1.0.0 – 3.1.1 | CommonJS | Dec 28, 2015 |

## Frequently asked

**Is path-key ESM-only?**

path-key@4.0.0 is ESM-only. path-key dropped its CommonJS build in 4.0.0 (April 2021). The last version with a plain require()-able CommonJS entry is 3.1.1, published Nov 22, 2019; it declares support for Node.js >=8.

**Which version of path-key still supports CommonJS / require()?**

3.1.1 is the last version of path-key with a CommonJS build; it declares Node.js >=8. Install it with "npm install path-key@3.1.1". Every version from 4.0.0 on is ESM-only.

**How do I use path-key from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const pathKey = await import("path-key"). That works on every Node.js version the package supports (>=12). On Node.js 20.19+, 22.12+ and newer, require("path-key") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin path-key@3.1.1 (declares Node.js >=8).

**Does path-key work in Bun?**

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

**Does path-key ship TypeScript types?**

Not bundled. Install the community types with "npm install -D @types/path-key".

## Links

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

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