Zero Config, Zero FOUC, Zero Runtime, CSS in JS Preprocessor

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English | 한국어

Install

npm install @devup-ui/react

# on next.js
npm install @devup-ui/next-plugin

# on vite
npm install @devup-ui/vite-plugin

# on rsbuild
npm install @devup-ui/rsbuild-plugin

# on webpack
npm install @devup-ui/webpack-plugin

Features

• Preprocessor
• Zero Config
• Zero FOUC
• Zero Runtime
• RSC Support
• Must not use JavaScript, client-side logic, or hybrid solutions
• Support Library mode
• Zero Cost Dynamic Theme Support based on CSS Variables
• Theme with Typing
• Smallest size, fastest speed

Inspirations

• Styled System
• Chakra UI
• Theme UI
• Vanilla Extract
• Rainbow Sprinkles
• Kuma UI

Comparison Benchmarks

Next.js Build Time and Build Size (github action - ubuntu-latest)

Library	Version	Build Time	Build Size
tailwindcss	4.1.13	20.22s	57,415,796 bytes
styleX	0.15.4	38.97s	76,257,820 bytes
vanilla-extract	1.17.4	20.09s	59,366,237 bytes
kuma-ui	1.5.9	21.61s	67,422,085 bytes
panda-css	1.3.1	22.01s	62,431,065 bytes
chakra-ui	3.27.0	29.99s	210,122,493 bytes
mui	7.3.2	22.21s	94,231,958 bytes
devup-ui(per-file css)	1.0.18	18.23s	57,440,953 bytes
devup-ui(single css)	1.0.18	18.35s	57,409,008 bytes

How it works

Devup UI is a CSS in JS preprocessor that does not require runtime. Devup UI eliminates the performance degradation of the browser through the CSS in JS preprocessor. We develop a preprocessor that considers all grammatical cases.

const before = <Box bg="red" />

const after = <div className="d0" />

Variables are fully supported.

const before = <Box bg={colorVariable} />

const after = (
  <div
    className="d0"
    style={{
      '--d0': colorVariable,
    }}
  />
)

Various expressions and responsiveness are also fully supported.

const before = <Box bg={['red', 'blue', a > b ? 'yellow' : variable]} />

const after = (
  <div
    className={`d0 d1 ${a > b ? 'd2' : 'd3'}`}
    style={{
      '--d2': variable,
    }}
  />
)

Support Theme with Typing

devup.json

{
  "theme": {
    "colors": {
      "default": {
        "text": "#000"
      },
      "dark": {
        "text": "white"
      }
    }
  }
}

// Type Safe
<Text color="$text" />

Support Responsive And Pseudo Selector

You can use responsive and pseudo selector.

// Responsive with Selector
const box = <Box _hover={{ bg: ['red', 'blue'] }} />

// Same
const box = <Box _hover={[{ bg: 'red' }, { bg: 'blue' }]} />

How to Contribute

Requirements

• Node.js (LTS version recommended)
• Rust compiler
• pnpm package manager (npm install -g pnpm)

Development Setup

To set up the development environment, install the following packages:

pnpm i
pnpm build
cargo install cargo-tarpaulin
cargo install wasm-pack

After installation, run pnpm test to ensure everything works correctly.