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

> nth-check@3.0.1 is ESM-only. ESM-only since 3.0.0 — last CommonJS version is 2.1.1.

Parses and compiles CSS nth-checks to highly optimized functions.

Last verified Sep 9, 2026 against nth-check@3.0.1.

nth-check dropped its CommonJS build in 3.0.0 (March 2026). The last version with a plain require()-able CommonJS entry is 2.1.1, published May 23, 2022.

On Node.js 20.19+, 22.12+ and newer, require("nth-check") 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 nth-check@3.0.1 declares Node.js >=20.19.0, so 18 is outside its supported range anyway.

nth-check@3.0.1 declares engines ">=20.19.0", 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("nth-check") 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 nthCheck = await import("nth-check"). That works on every Node.js version the package supports (>=20.19.0).
3. If you need a synchronous require() or run Node.js 18: npm install nth-check@2.1.1, the last CommonJS release (published May 23, 2022).
4. nth-check@3.0.1 declares engines ">=20.19.0", 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: 3.0.1 (Mar 17, 2026)
- Module format: ESM-only
- Last CommonJS version: 2.1.1
- ESM-only since: 3.0.0 (Mar 17, 2026)
- TypeScript types: bundled
- Node engines: >=20.19.0
- Weekly downloads: 49.4M
- License: BSD-2-Clause

## Runtime test results for nth-check@3.0.1

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

| Runtime | require("nth-check") | import "nth-check" |
|---|---|---|
| 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 nth-check

ES modules:

```js
import * as nthCheck from "nth-check";
```

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 nthCheck = require("nth-check");

// Any Node.js version the package supports (>=20.19.0), from an async function:
async function main() {
  const nthCheck = await import("nth-check");
}

// Or pin the last CommonJS release:
// npm install nth-check@2.1.1
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (9 versions; the newest 9 shown).

| Versions | Format | First published |
|---|---|---|
| 3.0.0 – 3.0.1 | ESM-only | Mar 17, 2026 |
| 2.1.0 – 2.1.1 | Dual (CommonJS + ESM) | May 22, 2022 |
| 1.0.0 – 2.0.1 | CommonJS | Feb 15, 2014 |

## Frequently asked

**Is nth-check ESM-only?**

nth-check@3.0.1 is ESM-only. nth-check dropped its CommonJS build in 3.0.0 (March 2026). The last version with a plain require()-able CommonJS entry is 2.1.1, published May 23, 2022.

**Which version of nth-check still supports CommonJS / require()?**

2.1.1 is the last version of nth-check with a CommonJS build. Install it with "npm install nth-check@2.1.1". Every version from 3.0.0 on is ESM-only.

**How do I use nth-check from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const nthCheck = await import("nth-check"). That works on every Node.js version the package supports (>=20.19.0). On Node.js 20.19+, 22.12+ and newer, require("nth-check") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin nth-check@2.1.1.

**Does nth-check work in Bun?**

Yes. import "nth-check" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does nth-check ship TypeScript types?**

Yes. nth-check bundles its own type declarations; no @types package is needed.

## Links

- [nth-check on npm](https://www.npmjs.com/package/nth-check)
- [Source repository](https://github.com/fb55/nth-check)
- [HTML version](https://canirequire.com/package/nth-check/)
- [JSON version](https://canirequire.com/package/nth-check.json)

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