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

> core-js@3.50.0 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Standard library

Last verified Sep 9, 2026 against core-js@3.50.0.

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

## Facts

- Latest: 3.50.0 (Aug 5, 2026)
- Module format: CommonJS
- Last CommonJS version: 3.50.0
- TypeScript types: @types/core-js
- Node engines: *
- Weekly downloads: 61.6M
- License: MIT

## Runtime test results for core-js@3.50.0

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

| Runtime | require("core-js") | import "core-js" |
|---|---|---|
| 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 core-js

ES modules:

```js
import coreJs from "core-js";
```

CommonJS:

```js
const coreJs = require("core-js");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (260 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 3.22.5 – 3.50.0 | CommonJS | May 10, 2022 |

## Frequently asked

**Is core-js ESM-only?**

core-js@3.50.0 is a CommonJS package. core-js ships CommonJS only. require("core-js") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js *. import "core-js" 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 core-js with ES module syntax?**

Yes. import coreJs from "core-js" 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 core-js work in Bun?**

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

**Does core-js ship TypeScript types?**

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

## Links

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

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