class-variant

Features

Vanilla, Next, React, Vue, Tailwind CSS, and Master CSS are available:

• ⚡️ Ultra-lightweight ~1.5KB, powered by Proxy
• 🛡️ Type safety
• 🌈 Dynamically change styles based on properties
• 💫 Re-expand existing elements, like NextLink
• 🧩 Compatible with server and client components
• 🪄 Built-in first-class clsx handling

Why?

😰 Before: Creating a simple styled element using a FunctionalComponent is unpleasant.

function Button(props) {
    return (
        <button>
            {props.children}
        </button>
    )
}

🥳 After: It's in one line and ~80% code less.

import styled from '@master/styled.react' // or .vue

const Button = styled.button`inline-flex font:14`

Apply it as usual:

export default function App() {
    return (
        <button>submit</button>
    )
}

It will be rendered as:

<button class="inline-flex font:14 uppercase">submit</button>

Getting Started

Install the package depending on your framework:

Vanilla

npm install class-variant

import cv from 'class-variant'

const btn = cv(...params)
const btn = cv`...` // or

btn(props) // -> string

React

npm install @master/styled.react

import styled from '@master/styled.react'

const Button = styled.button(...params)
const Button = styled.button`...` // or

<button>

Vue

npm install @master/styled.vue

import styled from '@master/styled.vue'

const Button = styled.button(...params)
const Button = styled.button`...` // or

</button><button>

Basic usage

Create a styled element

Declared in two ways: function or template literal, and parameters inherit all features of clsx.

const Element = styled.div`flex text:center`
const Element = styled.div('flex text:center') // or

return (
    <element>Hello World</element>
)

<div class="flex text:center uppercase">Hello World</div>

Apply based on predefined variants

Predefine the class variant corresponding to the property.

const Button = styled.button('flex', {
    $size: {
        sm: 'font:12 size:8x',
        md: 'font:14 size:12x'
    },
    disabled: 'opacity:.5',
    ...
})

return (
    </button><button disabled="">
)

</button><button disabled="" class="flex font:12 size:8x opacity:.5"></button>

> ⚠️ Custom properties that are not element-owned properties must be prefixed with $prop, otherwise they will be reflected on the final element and an error may be thrown.

You can set default properties for elements.

Button.default = {
    $size: 'md'
}

return (
    <button>
)

</button><button class="font:14 size:12x"></button>

Apply based on function properties

Dynamically apply class names based on function properties.

const Element = styled.div('fg:white',
    ({ $color }) => $color && `bg:${$color}`
)

return (
    <element>
)

<div class="inline-flex text:center fg:white bg:blue"></div>

Apply based on matching properties

Applies the target class name matching all specified property keys and their values.

const Button = styled.button('inline-flex',
    ['uppercase', { $intent: 'primary', $size: 'md' }]
)

return (
    <button>Not matched</button>
    <button>Not matched</button>
    <button>Matched</button>
)

<button class="inline-flex">Not matched</button>
<button class="inline-flex">Not matched</button>
<button class="inline-flex uppercase">Matched</button>

Extended

Extend a styled element

Extend an existing styled element and add additional classes or conditions.

const A = styled.p('a')
const B = styled.p(A)`b`

return (
    <a>A</a>
    <b>B</b>
)

<p class="a">A</p>
<p class="a b">B</p>

It also supports client components, taking Next.js’s Link as an example:

'use client'

import styled from '@master/styled.react';
import Link from 'next/link';

const Button = styled(Link)`inline-flex text:center`

return (
    <button>Submit</button>
)

> ⚠️ If the extended target contains client components, the 'use client' directive is required.

Change an element's tag name

Changing the original tag name of an element, such as <button> to <a>. Left empty '' even if there are no additional classes.

const Button = styled.button('inline-flex')
const Link = styled.a(Button)``

return (
    </a></button><a><button>button</button>
    link
)

<button class="inline-flex">button</button>
</a><a href="#example" class="inline-flex">link</a>

Extend multiple styled elements

Extend multiple style elements at once.

const A = styled.p`a`
const B = styled.p`b`
const C = styled.p`c`
const D = styled(A)(B)(C)`d`

return (
    <a>A</a>
    <b>B</b>
    C
    D
)

<p class="a">A</p>
<p class="b">B</p>
<p class="c">C</p>
<p class="a b c d">D</p>

Typings

declare type Props = {
    $size: 'sm' | 'md'
}

const Button = styled.button('flex', {
    $size: {
        sm: 'font:12 size:8x',
        md: 'font:14 size:12x'
    },
    disabled: 'opacity:.5'
})

Overview class-variant APIs

import cv from 'class-variant'

const btn = cv(
    'inline-flex rounded',
    {
        intent: {
            primary: 'bg:blue fg:white bg:blue-60:hover',
            secondary: 'bg:white fg:slate-30 bg:slate-90:hover',
        },
        size: {
            sm: 'text:14 p:5|15',
            md: 'text:16 p:10|25'
        }
    },
    ['uppercase', { intent: 'primary', size: 'md' }],
    ({ indent, size }) => indent && size && 'font:semibold'
)

btn.default = {
    intent: 'primary',
    size: 'sm'
}

btn()
// inline-flex rounded bg:blue fg:white bg:blue-55:hover text:14 p:5|8 font:semibold

btn({ indent: 'secondary', size: 'sm' })
// inline-flex rounded bg:white fg:slate-30 bg:slate-90:hover text:14 p:5|8 font:semibold

btn({ indent: 'primary', size: 'md' })
// inline-flex rounded bg:blue fg:white bg:blue-55:hover text:16 p:10|25 uppercase font:semibold

Community

The Master community can be found here:

• Discuss on GitHub - Ask questions, voice ideas, and do any other discussion
• Join our Discord Server - Casually chat with other people using the language ^{_{✓ 中文}}

_{Our 《 Code of Conduct 》 applies to all Master community channels.}

Contributing

Please see our CONTRIBUTING for workflow.

Inspiration

Some of our core concepts and designs are inspired by these giants.

• Template Literal - The use of template literals as syntactic sugar for reusing components is inspired by Styled Components.