canirequire

canirequire › ESM-only › leven

Is leven ESM-only? Can you require() it?

Measure the difference between two strings using the Levenshtein distance algorithm

Last verified Sep 9, 2026 against leven@4.1.0. Markdown · JSON

ESM-only ESM-only since 4.0.0 — last CommonJS version is 3.1.0

leven dropped its CommonJS build in 4.0.0 (August 2021). The last version with a plain require()-able CommonJS entry is 3.1.0, published Apr 4, 2019; it declares support for Node.js >=6.

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

What to do

  1. On Node.js 20.19+, 22.12+ and newer, require("leven") 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 leven = await import("leven"). That works on every Node.js version the package supports (^12.20.0 || ^14.13.1 || >=16.0.0).
  3. If you need a synchronous require() or run Node.js 18: npm install leven@3.1.0, the last CommonJS release (published Apr 4, 2019); it declares Node.js >=6.
  4. TypeScript: types are bundled; install nothing extra.
Latest
4.1.0 (Sep 11, 2025)
Module format
ESM-only
Last CommonJS version
3.1.0
ESM-only since
4.0.0 (Aug 10, 2021)
TypeScript types
Bundled
Node engines
^12.20.0 || ^14.13.1 || >=16.0.0
Weekly downloads
57.5M
License
MIT

Does leven@4.1.0 actually load? Runtime test results

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

Runtimerequire("leven")import "leven"
Node.js 18✗ failsERR_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 leven

ES modules (import)

import * as leven from "leven";

Namespace import shown because the ESM entry may have no default export; use named imports for what it exports.

CommonJS (require)

// Node.js 20.19+, 22.12+ and newer (verified):
const leven = require("leven");

// Any Node.js version the package supports (^12.20.0 || ^14.13.1 || >=16.0.0), from an async function:
async function main() {
  const leven = await import("leven");
}

// Or pin the last CommonJS release (declares Node.js >=6):
// npm install leven@3.1.0

Module format by version

Derived from the type, main and exports fields of every stable release on npm, corrected where a runtime test of that version contradicted them (9 versions; the newest 9 shown).

VersionsFormatFirst published
4.0.0 – 4.1.0ESM-onlyAug 10, 2021
1.0.0 – 3.1.0CommonJSAug 9, 2014

Frequently asked

Is leven ESM-only?

leven@4.1.0 is ESM-only. leven dropped its CommonJS build in 4.0.0 (August 2021). The last version with a plain require()-able CommonJS entry is 3.1.0, published Apr 4, 2019; it declares support for Node.js >=6.

Which version of leven still supports CommonJS / require()?

3.1.0 is the last version of leven with a CommonJS build; it declares Node.js >=6. Install it with "npm install leven@3.1.0". Every version from 4.0.0 on is ESM-only.

How do I use leven from a CommonJS file?

From a CommonJS file, use a dynamic import inside an async function: const leven = await import("leven"). That works on every Node.js version the package supports (^12.20.0 || ^14.13.1 || >=16.0.0). On Node.js 20.19+, 22.12+ and newer, require("leven") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin leven@3.1.0 (declares Node.js >=6).

Does leven work in Bun?

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

Does leven ship TypeScript types?

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

Links

Other esm-only packages

Similar popularity