clsx

A tiny (239B) utility for constructing className strings conditionally.
Also serves as a faster & smaller drop-in replacement for the classnames module.

This module is available in three formats:

ES Module: dist/clsx.mjs
CommonJS: dist/clsx.js
UMD: dist/clsx.min.js

Install

$ npm install --save clsx

Usage

import clsx from 'clsx';
// or
import { clsx } from 'clsx';

// Strings (variadic)
clsx('foo', true && 'bar', 'baz');
//=> 'foo bar baz'

// Objects
clsx({ foo:true, bar:false, baz:isTrue() });
//=> 'foo baz'

// Objects (variadic)
clsx({ foo:true }, { bar:false }, null, { '--foobar':'hello' });
//=> 'foo --foobar'

// Arrays
clsx(['foo', 0, false, 'bar']);
//=> 'foo bar'

// Arrays (variadic)
clsx(['foo'], ['', 0, false, 'bar'], [['baz', [['hello'], 'there']]]);
//=> 'foo bar baz hello there'

// Kitchen sink (with nesting)
clsx('foo', [1 && 'bar', { baz:false, bat:null }, ['hello', ['world']]], 'cya');
//=> 'foo bar hello world cya'

API

clsx(...input)

Returns: String

input

Type: Mixed

The clsx function can take any number of arguments, each of which can be an Object, Array, Boolean, or String.

Important: Any falsey values are discarded!
Standalone Boolean values are discarded as well.

clsx(true, false, '', null, undefined, 0, NaN);
//=> ''

Modes

There are multiple "versions" of clsx available, which allows you to bring only the functionality you need!

`clsx`

Size (gzip): 239 bytes
Availability: CommonJS, ES Module, UMD

The default clsx module; see API for info.

import { clsx } from 'clsx';
// or
import clsx from 'clsx';

`clsx/lite`

Size (gzip): 140 bytes
Availability: CommonJS, ES Module
CAUTION: Accepts ONLY string arguments!

Ideal for applications that only use the string-builder pattern.

Any non-string arguments are ignored!

import { clsx } from 'clsx/lite';
// or
import clsx from 'clsx/lite';

// string
clsx('hello', true && 'foo', false && 'bar');
// => "hello foo"

// NOTE: Any non-string input(s) ignored
clsx({ foo: true });
//=> ""

Benchmarks

For snapshots of cross-browser results, check out the bench directory~!

Support

All versions of Node.js are supported.

All browsers that support Array.isArray are supported (IE9+).

Note: For IE8 support and older, please install clsx@1.0.x and beware of #17.

Tailwind Support

Here some additional (optional) steps to enable classes autocompletion using clsx with Tailwind CSS.

Visual Studio Code

Install the "Tailwind CSS IntelliSense" Visual Studio Code extension
Add the following to your settings.json:

 {
  "tailwindCSS.experimental.classRegex": [
    ["clsx\\(([^)]*)\\)", "(?:'|\"|`)([^']*)(?:'|\"|`)"]
  ]
 }

You may find the clsx/lite module useful within Tailwind contexts. This is especially true if/when your application only composes classes in this pattern:

clsx('text-base', props.active && 'text-primary', props.className);

obj-str - A smaller (96B) and similiar utility that only works with Objects.

lukeed/clsx