# Is @sinonjs/fake-timers ESM-only? Can you require() it?

> @sinonjs/fake-timers@15.4.0 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Fake JavaScript timers

Last verified Sep 9, 2026 against @sinonjs/fake-timers@15.4.0.

@sinonjs/fake-timers ships CommonJS only. require("@sinonjs/fake-timers") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "@sinonjs/fake-timers" 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("@sinonjs/fake-timers") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun.
2. From ES modules use the default import: import fakeTimers from "@sinonjs/fake-timers"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 15.4.0 (May 5, 2026)
- Module format: CommonJS
- Last CommonJS version: 15.4.0
- TypeScript types: bundled
- Node engines: not declared
- Weekly downloads: 49.4M
- License: BSD-3-Clause

## Runtime test results for @sinonjs/fake-timers@15.4.0

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

| Runtime | require("@sinonjs/fake-timers") | import "@sinonjs/fake-timers" |
|---|---|---|
| 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 @sinonjs/fake-timers

ES modules:

```js
import fakeTimers from "@sinonjs/fake-timers";
```

CommonJS:

```js
const fakeTimers = require("@sinonjs/fake-timers");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (49 versions; the newest 49 shown).

| Versions | Format | First published |
|---|---|---|
| 6.0.0 – 15.4.0 | CommonJS | Feb 4, 2020 |

## Frequently asked

**Is @sinonjs/fake-timers ESM-only?**

@sinonjs/fake-timers@15.4.0 is a CommonJS package. @sinonjs/fake-timers ships CommonJS only. require("@sinonjs/fake-timers") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "@sinonjs/fake-timers" 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 @sinonjs/fake-timers with ES module syntax?**

Yes. import fakeTimers from "@sinonjs/fake-timers" 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 @sinonjs/fake-timers work in Bun?**

Yes. import "@sinonjs/fake-timers" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does @sinonjs/fake-timers ship TypeScript types?**

Yes. @sinonjs/fake-timers bundles its own type declarations; no @types package is needed.

## Links

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

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