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. 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 you can require() on every Node.js version, including 18 and older, is 3.1.0, published Apr 4, 2019.
On Node.js 20.19+, 22.12+ and every newer release, require("leven") works anyway: Node can load synchronous ES modules through require(). Verified on Node 20, 22, 24, 26. Node.js 18 and older still fail with ERR_REQUIRE_ESM.
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.
| Runtime | require("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 | ✓ works | ✓ works |
How to import leven
ES modules (import)
import leven from "leven";CommonJS (require)
// Node.js 20.19+ / 22.12+ / newer (package has no top-level await):
const leven = require("leven");
// Any Node.js version:
const leven = await import("leven");
// Or pin the last CommonJS release:
// npm install leven@3.1.0Module format by version
Derived from the type, main and exports fields of every stable release on npm (9 versions; the newest 9 shown).
| Versions | Format | First published |
|---|---|---|
| 4.0.0 – 4.1.0 | ESM-only | Aug 10, 2021 |
| 1.0.0 – 3.1.0 | CommonJS | Aug 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 you can require() on every Node.js version, including 18 and older, is 3.1.0, published Apr 4, 2019.
Which version of leven still supports CommonJS / require()?
3.1.0 is the last version of leven with a CommonJS build. 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?
Use a dynamic import: const mod = await import("leven"). On Node.js 20.19+, 22.12+ and newer, a plain require("leven") also works for ESM packages that do not use top-level await. Alternatively pin leven@3.1.0.
Does leven work in Bun?
Yes. import "leven" loaded successfully in Bun 1.4 on Sep 9, 2026.
Does leven ship TypeScript types?
Yes. leven bundles its own type declarations; no @types package is needed.
Links
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