# Is @nestjs/testing ESM-only? Can you require() it?

> @nestjs/testing@12.0.1 is ESM-only. ESM-only since 12.0.0 — last CommonJS version is 11.2.3.

Nest - modern, fast, powerful node.js web framework (@testing)

Last verified Sep 9, 2026 against @nestjs/testing@12.0.1.

@nestjs/testing dropped its CommonJS build in 12.0.0 (August 2026). The last version with a plain require()-able CommonJS entry is 11.2.3, published Aug 25, 2026.

On Node.js 20.19+, 22.12+ and newer, require("@nestjs/testing") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. On Node.js 18, which has no require(esm), require("@nestjs/testing") fails with ERR_REQUIRE_ESM.

## What to do

1. On Node.js 20.19+, 22.12+ and newer, require("@nestjs/testing") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26.
2. From a CommonJS file, use a dynamic import inside an async function: const testing = await import("@nestjs/testing"). That works on every Node.js version the package supports.
3. If you need a synchronous require() or run Node.js 18: npm install @nestjs/testing@11.2.3, the last CommonJS release (published Aug 25, 2026).
4. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 12.0.1 (Aug 27, 2026)
- Module format: ESM-only
- Last CommonJS version: 11.2.3
- ESM-only since: 12.0.0 (Aug 27, 2026)
- TypeScript types: bundled
- Node engines: not declared
- Weekly downloads: 6.4M
- License: MIT

## Runtime test results for @nestjs/testing@12.0.1

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

| Runtime | require("@nestjs/testing") | import "@nestjs/testing" |
|---|---|---|
| Node.js 18 | fails (ERR_REQUIRE_ESM) | 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 @nestjs/testing

ES modules:

```js
import * as testing from "@nestjs/testing";
```

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

CommonJS:

```js
// Node.js 20.19+, 22.12+ and newer (verified):
const testing = require("@nestjs/testing");

// Any Node.js version the package supports, from an async function:
async function main() {
  const testing = await import("@nestjs/testing");
}

// Or pin the last CommonJS release:
// npm install @nestjs/testing@11.2.3
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (361 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 12.0.0 – 12.0.1 | ESM-only | Aug 27, 2026 |
| 10.4.21 – 11.2.3 | CommonJS | Jan 8, 2026 |

## Frequently asked

**Is @nestjs/testing ESM-only?**

@nestjs/testing@12.0.1 is ESM-only. @nestjs/testing dropped its CommonJS build in 12.0.0 (August 2026). The last version with a plain require()-able CommonJS entry is 11.2.3, published Aug 25, 2026.

**Which version of @nestjs/testing still supports CommonJS / require()?**

11.2.3 is the last version of @nestjs/testing with a CommonJS build. Install it with "npm install @nestjs/testing@11.2.3". Every version from 12.0.0 on is ESM-only.

**How do I use @nestjs/testing from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const testing = await import("@nestjs/testing"). That works on every Node.js version the package supports. On Node.js 20.19+, 22.12+ and newer, require("@nestjs/testing") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin @nestjs/testing@11.2.3.

**Does @nestjs/testing work in Bun?**

Yes. import "@nestjs/testing" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does @nestjs/testing ship TypeScript types?**

Yes. @nestjs/testing bundles its own type declarations; no @types package is needed.

## Links

- [@nestjs/testing on npm](https://www.npmjs.com/package/@nestjs/testing)
- [Source repository](https://github.com/nestjs/nest)
- [HTML version](https://canirequire.com/package/@nestjs/testing/)
- [JSON version](https://canirequire.com/package/@nestjs/testing.json)

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