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

> yeoman-assert@3.1.1 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Assert utility from yeoman

Last verified Sep 9, 2026 against yeoman-assert@3.1.1.

yeoman-assert ships CommonJS only. require("yeoman-assert") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=4. import "yeoman-assert" 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.

**Deprecated:** This package is deprecated. See: https://github.com/yeoman/yeoman/issues/1779

## What to do

1. require("yeoman-assert") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=4.
2. From ES modules use the default import: import yeomanAssert from "yeoman-assert"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: npm install -D @types/yeoman-assert
4. This package is deprecated: This package is deprecated. See: https://github.com/yeoman/yeoman/issues/1779

## Facts

- Latest: 3.1.1 (Mar 25, 2018)
- Module format: CommonJS
- Last CommonJS version: 3.1.1
- TypeScript types: @types/yeoman-assert
- Node engines: >=4
- Weekly downloads: 38K
- License: BSD-2-Clause

## Runtime test results for yeoman-assert@3.1.1

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

| Runtime | require("yeoman-assert") | import "yeoman-assert" |
|---|---|---|
| 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 yeoman-assert

ES modules:

```js
import yeomanAssert from "yeoman-assert";
```

CommonJS:

```js
const yeomanAssert = require("yeoman-assert");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (12 versions; the newest 12 shown).

| Versions | Format | First published |
|---|---|---|
| 1.0.0 – 3.1.1 | CommonJS | Nov 16, 2014 |

## Frequently asked

**Is yeoman-assert ESM-only?**

yeoman-assert@3.1.1 is a CommonJS package. yeoman-assert ships CommonJS only. require("yeoman-assert") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. The package declares Node.js >=4. import "yeoman-assert" 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 yeoman-assert with ES module syntax?**

Yes. import yeomanAssert from "yeoman-assert" 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 yeoman-assert work in Bun?**

Yes. import "yeoman-assert" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does yeoman-assert ship TypeScript types?**

Not bundled. Install the community types with "npm install -D @types/yeoman-assert".

## Links

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

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