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

> slash@5.1.0 is ESM-only. ESM-only since 4.0.0 — last CommonJS version is 3.0.0.

Convert Windows backslash paths to slash paths

Last verified Sep 9, 2026 against slash@5.1.0.

slash dropped its CommonJS build in 4.0.0 (April 2021). The last version with a plain require()-able CommonJS entry is 3.0.0, published Apr 28, 2019; it declares support for Node.js >=8.

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

## What to do

1. On Node.js 20.19+, 22.12+ and newer, require("slash") 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 slash = await import("slash"). That works on every Node.js version the package supports (>=14.16).
3. If you need a synchronous require() or run Node.js 18: npm install slash@3.0.0, the last CommonJS release (published Apr 28, 2019); it declares Node.js >=8.
4. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 5.1.0 (May 9, 2023)
- Module format: ESM-only
- Last CommonJS version: 3.0.0
- ESM-only since: 4.0.0 (Apr 14, 2021)
- TypeScript types: bundled
- Node engines: >=14.16
- Weekly downloads: 121.9M
- License: MIT

## Runtime test results for slash@5.1.0

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

| Runtime | require("slash") | import "slash" |
|---|---|---|
| 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 slash

ES modules:

```js
import * as slash from "slash";
```

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 slash = require("slash");

// Any Node.js version the package supports (>=14.16), from an async function:
async function main() {
  const slash = await import("slash");
}

// Or pin the last CommonJS release (declares Node.js >=8):
// npm install slash@3.0.0
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (10 versions; the newest 10 shown).

| Versions | Format | First published |
|---|---|---|
| 4.0.0 – 5.1.0 | ESM-only | Apr 14, 2021 |
| 0.1.0 – 3.0.0 | CommonJS | Jul 18, 2013 |

## Frequently asked

**Is slash ESM-only?**

slash@5.1.0 is ESM-only. slash dropped its CommonJS build in 4.0.0 (April 2021). The last version with a plain require()-able CommonJS entry is 3.0.0, published Apr 28, 2019; it declares support for Node.js >=8.

**Which version of slash still supports CommonJS / require()?**

3.0.0 is the last version of slash with a CommonJS build; it declares Node.js >=8. Install it with "npm install slash@3.0.0". Every version from 4.0.0 on is ESM-only.

**How do I use slash from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const slash = await import("slash"). That works on every Node.js version the package supports (>=14.16). On Node.js 20.19+, 22.12+ and newer, require("slash") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin slash@3.0.0 (declares Node.js >=8).

**Does slash work in Bun?**

Yes. import "slash" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does slash ship TypeScript types?**

Yes. slash bundles its own type declarations; no @types package is needed.

## Links

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

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