# Is string-length ESM-only? Can you require() it?

> string-length@7.0.1 is ESM-only. ESM-only since 5.0.0 — last CommonJS version is 4.0.2.

Get the real length of a string - by correctly counting astral symbols and ignoring ansi escape codes

Last verified Sep 9, 2026 against string-length@7.0.1.

string-length dropped its CommonJS build in 5.0.0 (June 2021). The last version with a plain require()-able CommonJS entry is 4.0.2, published Mar 17, 2021; it declares support for Node.js >=10.

On Node.js 20.19+, 22.12+ and newer, require("string-length") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Node.js 18 has no require(esm), and string-length@7.0.1 declares Node.js >=20, so 18 is outside its supported range anyway.

string-length@7.0.1 declares engines ">=20", so Node.js 18 is outside its supported range regardless of module format.

## What to do

1. On Node.js 20.19+, 22.12+ and newer, require("string-length") 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 stringLength = await import("string-length"). That works on every Node.js version the package supports (>=20).
3. If you need a synchronous require() or run Node.js 18: npm install string-length@4.0.2, the last CommonJS release (published Mar 17, 2021); it declares Node.js >=10.
4. string-length@7.0.1 declares engines ">=20", so Node.js 18 is unsupported regardless: upgrade Node.js or pin an older release.
5. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 7.0.1 (Jan 21, 2026)
- Module format: ESM-only
- Last CommonJS version: 4.0.2
- ESM-only since: 5.0.0 (Jun 5, 2021)
- TypeScript types: bundled
- Node engines: >=20
- Weekly downloads: 46.6M
- License: MIT

## Runtime test results for string-length@7.0.1

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

| Runtime | require("string-length") | import "string-length" |
|---|---|---|
| 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 string-length

ES modules:

```js
import * as stringLength from "string-length";
```

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 stringLength = require("string-length");

// Any Node.js version the package supports (>=20), from an async function:
async function main() {
  const stringLength = await import("string-length");
}

// Or pin the last CommonJS release (declares Node.js >=10):
// npm install string-length@4.0.2
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (16 versions; the newest 16 shown).

| Versions | Format | First published |
|---|---|---|
| 5.0.0 – 7.0.1 | ESM-only | Jun 5, 2021 |
| 0.1.0 – 4.0.2 | CommonJS | Apr 16, 2014 |

## Frequently asked

**Is string-length ESM-only?**

string-length@7.0.1 is ESM-only. string-length dropped its CommonJS build in 5.0.0 (June 2021). The last version with a plain require()-able CommonJS entry is 4.0.2, published Mar 17, 2021; it declares support for Node.js >=10.

**Which version of string-length still supports CommonJS / require()?**

4.0.2 is the last version of string-length with a CommonJS build; it declares Node.js >=10. Install it with "npm install string-length@4.0.2". Every version from 5.0.0 on is ESM-only.

**How do I use string-length from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const stringLength = await import("string-length"). That works on every Node.js version the package supports (>=20). On Node.js 20.19+, 22.12+ and newer, require("string-length") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin string-length@4.0.2 (declares Node.js >=10).

**Does string-length work in Bun?**

Yes. import "string-length" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does string-length ship TypeScript types?**

Yes. string-length bundles its own type declarations; no @types package is needed.

## Links

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

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