# Is karma-sourcemap-loader ESM-only? Can you require() it?

> karma-sourcemap-loader@0.4.0 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Karma plugin that locates and loads existing javascript source map files.

Last verified Sep 9, 2026 against karma-sourcemap-loader@0.4.0.

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

## Facts

- Latest: 0.4.0 (Feb 5, 2023)
- Module format: CommonJS
- Last CommonJS version: 0.4.0
- TypeScript types: none
- Node engines: not declared
- Weekly downloads: 391K
- License: MIT

## Runtime test results for karma-sourcemap-loader@0.4.0

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

| Runtime | require("karma-sourcemap-loader") | import "karma-sourcemap-loader" |
|---|---|---|
| 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 karma-sourcemap-loader

ES modules:

```js
import karmaSourcemapLoader from "karma-sourcemap-loader";
```

CommonJS:

```js
const karmaSourcemapLoader = require("karma-sourcemap-loader");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (13 versions; the newest 13 shown).

| Versions | Format | First published |
|---|---|---|
| 0.1.0 – 0.4.0 | CommonJS | Feb 18, 2014 |

## Frequently asked

**Is karma-sourcemap-loader ESM-only?**

karma-sourcemap-loader@0.4.0 is a CommonJS package. karma-sourcemap-loader ships CommonJS only. require("karma-sourcemap-loader") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "karma-sourcemap-loader" 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 karma-sourcemap-loader with ES module syntax?**

Yes. import karmaSourcemapLoader from "karma-sourcemap-loader" 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 karma-sourcemap-loader work in Bun?**

Yes. import "karma-sourcemap-loader" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does karma-sourcemap-loader ship TypeScript types?**

No. karma-sourcemap-loader ships no type declarations and there is no @types package for it.

## Links

- [karma-sourcemap-loader on npm](https://www.npmjs.com/package/karma-sourcemap-loader)
- [Source repository](https://github.com/demerzel3/karma-sourcemap-loader)
- [HTML version](https://canirequire.com/package/karma-sourcemap-loader/)
- [JSON version](https://canirequire.com/package/karma-sourcemap-loader.json)

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