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

> boolbase@2.0.0 is ESM-only. ESM-only since 2.0.0 — last CommonJS version is 1.0.0.

two functions: One that returns true, one that returns false

Last verified Sep 9, 2026 against boolbase@2.0.0.

boolbase dropped its CommonJS build in 2.0.0 (March 2026). The last version with a plain require()-able CommonJS entry is 1.0.0, published Feb 15, 2014.

On Node.js 20.19+, 22.12+ and newer, require("boolbase") 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 boolbase@2.0.0 declares Node.js >=20.19.0, so 18 is outside its supported range anyway.

boolbase@2.0.0 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("boolbase") 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 boolbase = await import("boolbase"). 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 boolbase@1.0.0, the last CommonJS release (published Feb 15, 2014).
4. boolbase@2.0.0 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: 2.0.0 (Mar 17, 2026)
- Module format: ESM-only
- Last CommonJS version: 1.0.0
- ESM-only since: 2.0.0 (Mar 17, 2026)
- TypeScript types: bundled
- Node engines: >=20.19.0
- Weekly downloads: 56.6M
- License: ISC

## Runtime test results for boolbase@2.0.0

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

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

ES modules:

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

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 boolbase = require("boolbase");

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

// Or pin the last CommonJS release:
// npm install boolbase@1.0.0
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (2 versions; the newest 2 shown).

| Versions | Format | First published |
|---|---|---|
| 2.0.0 | ESM-only | Mar 17, 2026 |
| 1.0.0 | CommonJS | Feb 15, 2014 |

## Frequently asked

**Is boolbase ESM-only?**

boolbase@2.0.0 is ESM-only. boolbase dropped its CommonJS build in 2.0.0 (March 2026). The last version with a plain require()-able CommonJS entry is 1.0.0, published Feb 15, 2014.

**Which version of boolbase still supports CommonJS / require()?**

1.0.0 is the last version of boolbase with a CommonJS build. Install it with "npm install boolbase@1.0.0". Every version from 2.0.0 on is ESM-only.

**How do I use boolbase from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const boolbase = await import("boolbase"). That works on every Node.js version the package supports (>=20.19.0). On Node.js 20.19+, 22.12+ and newer, require("boolbase") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin boolbase@1.0.0.

**Does boolbase work in Bun?**

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

**Does boolbase ship TypeScript types?**

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

## Links

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

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