The fastest and tiniest utility for conditionally joining classNames.

npm install classix

Use any amount of string expressions and classix will join them like so:

import cx from "classix";
// or
import { cx } from "classix";

cx("class1", "class2");
// => "class1 class2"

cx("class1 class2", "class3", "class4 class5");
// => "class1 class2 class3 class4 class5"

cx("class1", true && "class2");
// => "class1 class2"

cx(false && "class1", "class2");
// => "class2"

cx(true ? "class1" : "class2");
// => "class1"

cx("class1", false ? "class2" : "class3");
// => "class1 class3"

cx(...["class1", "class2", "class3"]);
// => class1 class2 class3

cx(
  "flex",
  isPrimary ? "bg-primary-100" : "bg-secondary-100",
  isLarge ? "m-4 p-4" : "m-2 p-2"
);
// => "flex bg-primary-100 m-2 p-2" *assuming isPrimary is true and isLarge is false

classix considers string expressions faster to type and easier to reason about (conditions first, followed by classNames) than the alternative:

// 🚫
clsx({ "class-1": isPrimary });
// ✅
cx(isPrimary && "class-1");

// 🚫
clsx({ "class-1": isPrimary && isLarge, "class-2": !isPrimary || !isLarge });
// ✅
cx(isPrimary && isLarge ? "class-1" : "class-2");

This reasoning enables classix to simplify its API by allowing only string expressions as arguments. Not only does it provide a consistent way of joining classNames, but using classix also leads to better performance and a smaller bundle size for your application.

Sources: classix, clsx, classnames

Sources: Ran benchmark on an AMD Ryzen 5 5600x.

• Supports all major browsers
• Supports all versions of Node.js
• Works with both ES Modules and CommonJS
• Zero dependencies
• Fully typed with TypeScript
• Fully tested
• Semver compliant

If you are using classnames or clsx, you can migrate to classix by changing your imports:

- import classnames from 'classnames';
  import cx from 'classix';

And if you were using object arguments, you'll have to convert them to string arguments:

- classnames({ 'class-1': cond });
  cx(cond && 'class-1')

That's it!

For a list of changes and releases, see the changelog.

Found a bug, have a question or looking to improve classix? Open an issue, start a discussion or submit a PR!