# Is side-channel-map ESM-only? Can you require() it?

> side-channel-map@1.0.1 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Store information about any JS value in a side channel, using a Map

Last verified Sep 9, 2026 against side-channel-map@1.0.1.

side-channel-map ships CommonJS only. require("side-channel-map") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.4. import "side-channel-map" 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("side-channel-map") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.4.
2. From ES modules use the default import: import sideChannelMap from "side-channel-map"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 1.0.1 (Dec 11, 2024)
- Module format: CommonJS
- Last CommonJS version: 1.0.1
- TypeScript types: bundled
- Node engines: >= 0.4
- Weekly downloads: 106.0M
- License: MIT

## Runtime test results for side-channel-map@1.0.1

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

| Runtime | require("side-channel-map") | import "side-channel-map" |
|---|---|---|
| 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 side-channel-map

ES modules:

```js
import sideChannelMap from "side-channel-map";
```

CommonJS:

```js
const sideChannelMap = require("side-channel-map");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (2 versions; the newest 2 shown).

| Versions | Format | First published |
|---|---|---|
| 1.0.0 – 1.0.1 | CommonJS | Dec 10, 2024 |

## Frequently asked

**Is side-channel-map ESM-only?**

side-channel-map@1.0.1 is a CommonJS package. side-channel-map ships CommonJS only. require("side-channel-map") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >= 0.4. import "side-channel-map" 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 side-channel-map with ES module syntax?**

Yes. import sideChannelMap from "side-channel-map" 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 side-channel-map work in Bun?**

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

**Does side-channel-map ship TypeScript types?**

Yes. side-channel-map bundles its own type declarations; no @types package is needed.

## Links

- [side-channel-map on npm](https://www.npmjs.com/package/side-channel-map)
- [Source repository](https://github.com/ljharb/side-channel-map)
- [HTML version](https://canirequire.com/package/side-channel-map/)
- [JSON version](https://canirequire.com/package/side-channel-map.json)

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