# Is fast-deep-equal ESM-only? Can you require() it?

> fast-deep-equal@3.1.3 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

Fast deep equal

Last verified Sep 9, 2026 against fast-deep-equal@3.1.3.

fast-deep-equal ships CommonJS only. require("fast-deep-equal") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "fast-deep-equal" 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("fast-deep-equal") 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 fastDeepEqual from "fast-deep-equal"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 3.1.3 (Jun 8, 2020)
- Module format: CommonJS
- Last CommonJS version: 3.1.3
- TypeScript types: bundled
- Node engines: not declared
- Weekly downloads: 180.3M
- License: MIT

## Runtime test results for fast-deep-equal@3.1.3

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

| Runtime | require("fast-deep-equal") | import "fast-deep-equal" |
|---|---|---|
| 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 fast-deep-equal

ES modules:

```js
import fastDeepEqual from "fast-deep-equal";
```

CommonJS:

```js
const fastDeepEqual = require("fast-deep-equal");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (11 versions; the newest 11 shown).

| Versions | Format | First published |
|---|---|---|
| 0.0.1 – 3.1.3 | CommonJS | Jun 15, 2017 |

## Frequently asked

**Is fast-deep-equal ESM-only?**

fast-deep-equal@3.1.3 is a CommonJS package. fast-deep-equal ships CommonJS only. require("fast-deep-equal") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "fast-deep-equal" 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 fast-deep-equal with ES module syntax?**

Yes. import fastDeepEqual from "fast-deep-equal" 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 fast-deep-equal work in Bun?**

Yes. import "fast-deep-equal" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does fast-deep-equal ship TypeScript types?**

Yes. fast-deep-equal bundles its own type declarations; no @types package is needed.

## Links

- [fast-deep-equal on npm](https://www.npmjs.com/package/fast-deep-equal)
- [Source repository](https://github.com/epoberezkin/fast-deep-equal)
- [HTML version](https://canirequire.com/package/fast-deep-equal/)
- [JSON version](https://canirequire.com/package/fast-deep-equal.json)

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