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

> error-ex@1.3.4 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Easy error subclassing and stack customization

Last verified Sep 9, 2026 against error-ex@1.3.4.

error-ex ships CommonJS only. require("error-ex") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "error-ex" 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("error-ex") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun.
2. From ES modules use the default import: import errorEx from "error-ex"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: no types are available for error-ex; declare the module yourself if you need them.

## Facts

- Latest: 1.3.4 (Sep 15, 2025)
- Module format: CommonJS
- Last CommonJS version: 1.3.4
- TypeScript types: none
- Node engines: not declared
- Weekly downloads: 67.2M
- License: MIT

## Runtime test results for error-ex@1.3.4

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

| Runtime | require("error-ex") | import "error-ex" |
|---|---|---|
| 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 error-ex

ES modules:

```js
import errorEx from "error-ex";
```

CommonJS:

```js
const errorEx = require("error-ex");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (17 versions; the newest 17 shown).

| Versions | Format | First published |
|---|---|---|
| 0.1.0 – 1.3.4 | CommonJS | Aug 25, 2015 |

## Frequently asked

**Is error-ex ESM-only?**

error-ex@1.3.4 is a CommonJS package. error-ex ships CommonJS only. require("error-ex") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "error-ex" 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 error-ex with ES module syntax?**

Yes. import errorEx from "error-ex" 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 error-ex work in Bun?**

Yes. import "error-ex" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does error-ex ship TypeScript types?**

No. error-ex ships no type declarations and there is no @types package for it.

## Links

- [error-ex on npm](https://www.npmjs.com/package/error-ex)
- [Source repository](https://github.com/qix-/node-error-ex)
- [HTML version](https://canirequire.com/package/error-ex/)
- [JSON version](https://canirequire.com/package/error-ex.json)

---

For scripts and AI agents: any package is at https://canirequire.com/package/<name>/index.md (Markdown) or https://canirequire.com/package/<name>.json (JSON); the site index is https://canirequire.com/llms.txt. Fetch the URL directly; no search needed.