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

> deep-eql@5.0.2 is ESM-only. ESM-only since 5.0.0 — last CommonJS version is 4.1.4.

Improved deep equality testing for Node.js and the browser.

Last verified Sep 9, 2026 against deep-eql@5.0.2.

deep-eql dropped its CommonJS build in 5.0.0 (October 2023). The last version with a plain require()-able CommonJS entry is 4.1.4, published Jun 5, 2024; it declares support for Node.js >=6.

On Node.js 20.19+, 22.12+ and newer, require("deep-eql") 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("deep-eql") fails with ERR_REQUIRE_ESM.

## What to do

1. On Node.js 20.19+, 22.12+ and newer, require("deep-eql") 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 deepEql = await import("deep-eql"). That works on every Node.js version the package supports (>=6).
3. If you need a synchronous require() or run Node.js 18: npm install deep-eql@4.1.4, the last CommonJS release (published Jun 5, 2024); it declares Node.js >=6.
4. TypeScript: npm install -D @types/deep-eql

## Facts

- Latest: 5.0.2 (Jun 3, 2024)
- Module format: ESM-only
- Last CommonJS version: 4.1.4
- ESM-only since: 5.0.0 (Oct 18, 2023)
- TypeScript types: @types/deep-eql
- Node engines: >=6
- Weekly downloads: 51.2M
- License: MIT

## Runtime test results for deep-eql@5.0.2

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

| Runtime | require("deep-eql") | import "deep-eql" |
|---|---|---|
| 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 deep-eql

ES modules:

```js
import * as deepEql from "deep-eql";
```

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 deepEql = require("deep-eql");

// Any Node.js version the package supports (>=6), from an async function:
async function main() {
  const deepEql = await import("deep-eql");
}

// Or pin the last CommonJS release (declares Node.js >=6):
// npm install deep-eql@4.1.4
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (23 versions; the newest 23 shown).

| Versions | Format | First published |
|---|---|---|
| 5.0.0 – 5.0.2 | ESM-only | Oct 18, 2023 |
| 0.1.0 – 4.1.4 | CommonJS | Sep 18, 2013 |

## Frequently asked

**Is deep-eql ESM-only?**

deep-eql@5.0.2 is ESM-only. deep-eql dropped its CommonJS build in 5.0.0 (October 2023). The last version with a plain require()-able CommonJS entry is 4.1.4, published Jun 5, 2024; it declares support for Node.js >=6.

**Which version of deep-eql still supports CommonJS / require()?**

4.1.4 is the last version of deep-eql with a CommonJS build; it declares Node.js >=6. Install it with "npm install deep-eql@4.1.4". Every version from 5.0.0 on is ESM-only.

**How do I use deep-eql from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const deepEql = await import("deep-eql"). That works on every Node.js version the package supports (>=6). On Node.js 20.19+, 22.12+ and newer, require("deep-eql") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin deep-eql@4.1.4 (declares Node.js >=6).

**Does deep-eql work in Bun?**

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

**Does deep-eql ship TypeScript types?**

Not bundled. Install the community types with "npm install -D @types/deep-eql".

## Links

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

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