# Is log4js ESM-only? Can you require() it?

> log4js@6.9.1 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Port of Log4js to work with node.

Last verified Sep 9, 2026 against log4js@6.9.1.

log4js ships CommonJS only. require("log4js") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=8.0. import "log4js" 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("log4js") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=8.0.
2. From ES modules use the default import: import log4js from "log4js"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 6.9.1 (Mar 8, 2023)
- Module format: CommonJS
- Last CommonJS version: 6.9.1
- TypeScript types: bundled
- Node engines: >=8.0
- Weekly downloads: 5.0M
- License: Apache-2.0

## Runtime test results for log4js@6.9.1

Installed and executed on Sep 9, 2026 with require("log4js") from a CommonJS file and import "log4js" from an ES module.

| Runtime | require("log4js") | import "log4js" |
|---|---|---|
| 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 log4js

ES modules:

```js
import log4js from "log4js";
```

CommonJS:

```js
const log4js = require("log4js");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (152 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 2.5.1 – 6.9.1 | CommonJS | Jan 17, 2018 |

## Frequently asked

**Is log4js ESM-only?**

log4js@6.9.1 is a CommonJS package. log4js ships CommonJS only. require("log4js") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=8.0. import "log4js" 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 log4js with ES module syntax?**

Yes. import log4js from "log4js" 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 log4js work in Bun?**

Yes. import "log4js" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does log4js ship TypeScript types?**

Yes. log4js bundles its own type declarations; no @types package is needed.

## Links

- [log4js on npm](https://www.npmjs.com/package/log4js)
- [Source repository](https://github.com/log4js-node/log4js-node)
- [HTML version](https://canirequire.com/package/log4js/)
- [JSON version](https://canirequire.com/package/log4js.json)

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