canirequire › CommonJS › classnames
Is classnames ESM-only? Can you require() it?
A simple utility for conditionally joining classNames together
Last verified Sep 9, 2026 against classnames@2.5.1. JSON
CommonJS CommonJS — require() works on every Node.js version
classnames ships CommonJS only. require("classnames") works everywhere. import "classnames" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.
Does classnames@2.5.1 actually load? Runtime test results
Installed and executed on Sep 9, 2026 with require("classnames") from a CommonJS file and import "classnames" from an ES module.
| Runtime | require("classnames") | import "classnames" |
|---|---|---|
| Node.js 18 | ✓ works | ✓ 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 classnames
ES modules (import)
import classnames from "classnames";Named imports from a CommonJS package only work when Node.js can statically detect them. If a named import fails, use the default import and destructure.
CommonJS (require)
const classnames = require("classnames");Module format by version
Derived from the type, main and exports fields of every stable release on npm (30 versions; the newest 30 shown).
| Versions | Format | First published |
|---|---|---|
| 1.0.0 – 2.5.1 | CommonJS | Nov 5, 2014 |
Frequently asked
Is classnames ESM-only?
classnames@2.5.1 is a CommonJS package. classnames ships CommonJS only. require("classnames") works everywhere. import "classnames" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.
Can I import classnames with ES module syntax?
Yes. import classnames from "classnames" works in Node.js and Bun because they support importing CommonJS modules. Named imports work only when Node.js can statically detect the exports.
Does classnames work in Bun?
Yes. import "classnames" loaded successfully in Bun 1.4 on Sep 9, 2026.
Does classnames ship TypeScript types?
Yes. classnames bundles its own type declarations; no @types package is needed.
Links
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