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

> immer@11.1.18 ships CommonJS and ESM builds. Dual package — require() works on every Node.js version we test; import works too.

Create your next immutable state by mutating the current one

Last verified Sep 9, 2026 against immer@11.1.18.

immer publishes both a CommonJS entry and a native ESM entry (ESM added in 9.0.13). require("immer") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "immer" works alongside it.

## What to do

1. Nothing to change. require("immer") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import * as immer from "immer" works alongside it; use named imports for what the ESM entry exports.
2. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 11.1.18 (Aug 19, 2026)
- Module format: Dual (CommonJS + ESM)
- Last CommonJS version: 11.1.18
- Native ESM since: 9.0.13
- TypeScript types: bundled
- Node engines: not declared
- Weekly downloads: 54.5M
- License: MIT

## Runtime test results for immer@11.1.18

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

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

ES modules:

```js
import * as immer from "immer";
```

Namespace import shown because the ESM entry may have no default export; use named imports for what it exports.

CommonJS:

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

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (175 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 9.0.13 – 11.1.18 | Dual (CommonJS + ESM) | May 11, 2022 |
| 7.0.13 – 9.0.12 | CommonJS | Oct 20, 2020 |

## Frequently asked

**Is immer ESM-only?**

immer@11.1.18 ships CommonJS and ESM builds. immer publishes both a CommonJS entry and a native ESM entry (ESM added in 9.0.13). require("immer") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "immer" works alongside it.

**Can I require immer?**

Yes. immer ships a CommonJS entry alongside the native ESM entry. require("immer") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun.

**Does immer work in Bun?**

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

**Does immer ship TypeScript types?**

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

## Links

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

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