# Is is-core-module ESM-only? Can you require() it?

> is-core-module@2.16.2 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Is this specifier a node.js core module?

Last verified Sep 9, 2026 against is-core-module@2.16.2.

is-core-module ships CommonJS only. require("is-core-module") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.4. import "is-core-module" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

## What to do

1. require("is-core-module") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.4.
2. From ES modules use the default import: import isCoreModule from "is-core-module"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: npm install -D @types/is-core-module

## Facts

- Latest: 2.16.2 (May 5, 2026)
- Module format: CommonJS
- Last CommonJS version: 2.16.2
- TypeScript types: @types/is-core-module
- Node engines: >= 0.4
- Weekly downloads: 105.9M
- License: MIT

## Runtime test results for is-core-module@2.16.2

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

| Runtime | require("is-core-module") | import "is-core-module" |
|---|---|---|
| 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 is-core-module

ES modules:

```js
import isCoreModule from "is-core-module";
```

CommonJS:

```js
const isCoreModule = require("is-core-module");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (26 versions; the newest 26 shown).

| Versions | Format | First published |
|---|---|---|
| 1.0.0 – 2.16.2 | CommonJS | Sep 29, 2014 |

## Frequently asked

**Is is-core-module ESM-only?**

is-core-module@2.16.2 is a CommonJS package. is-core-module ships CommonJS only. require("is-core-module") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.4. import "is-core-module" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

**Can I import is-core-module with ES module syntax?**

Yes. import isCoreModule from "is-core-module" works in Node.js and Bun because they support importing CommonJS modules. Named imports work only when Node.js can statically detect the exports.

**Does is-core-module work in Bun?**

Yes. import "is-core-module" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does is-core-module ship TypeScript types?**

Not bundled. Install the community types with "npm install -D @types/is-core-module".

## Links

- [is-core-module on npm](https://www.npmjs.com/package/is-core-module)
- [Source repository](https://github.com/inspect-js/is-core-module)
- [HTML version](https://canirequire.com/package/is-core-module/)
- [JSON version](https://canirequire.com/package/is-core-module.json)

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