# Is source-map-loader ESM-only? Can you require() it?

> source-map-loader@5.0.0 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

extracts inlined source map and offers it to webpack

Last verified Sep 9, 2026 against source-map-loader@5.0.0.

source-map-loader ships CommonJS only. require("source-map-loader") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 18.12.0. import "source-map-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("source-map-loader") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 18.12.0.
2. From ES modules use the default import: import sourceMapLoader from "source-map-loader"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: no types are available for source-map-loader; declare the module yourself if you need them.

## Facts

- Latest: 5.0.0 (Jan 15, 2024)
- Module format: CommonJS
- Last CommonJS version: 5.0.0
- TypeScript types: none
- Node engines: >= 18.12.0
- Weekly downloads: 10.8M
- License: MIT

## Runtime test results for source-map-loader@5.0.0

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

| Runtime | require("source-map-loader") | import "source-map-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 source-map-loader

ES modules:

```js
import sourceMapLoader from "source-map-loader";
```

CommonJS:

```js
const sourceMapLoader = require("source-map-loader");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (29 versions; the newest 29 shown).

| Versions | Format | First published |
|---|---|---|
| 0.1.0 – 5.0.0 | CommonJS | May 22, 2014 |

## Frequently asked

**Is source-map-loader ESM-only?**

source-map-loader@5.0.0 is a CommonJS package. source-map-loader ships CommonJS only. require("source-map-loader") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 18.12.0. import "source-map-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 source-map-loader with ES module syntax?**

Yes. import sourceMapLoader from "source-map-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 source-map-loader work in Bun?**

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

**Does source-map-loader ship TypeScript types?**

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

## Links

- [source-map-loader on npm](https://www.npmjs.com/package/source-map-loader)
- [Source repository](https://github.com/webpack-contrib/source-map-loader)
- [HTML version](https://canirequire.com/package/source-map-loader/)
- [JSON version](https://canirequire.com/package/source-map-loader.json)

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