css-render ·

Generating CSS using JS with considerable flexibility and extensibility, at both server side and client side.

It's mainly built for library builders (who wants make their library work without css import at small overhead). It's not recommend to use it in a webapp.

It is not designed to totally replace other style-related solutions, but to be a progressive tool which can just work as a supplementary of your style files or totally replace your .css files.

Docs

css-render

Why Using It

You want to ship a library without css at a small price (gzip < 2kb).
Reduce size compared with static css (which contains duplicate logic).
You can't write sass-like or less-like css-in-js (eg. mixin in sass or less).
You want to write style variables in JS.
Support an simple SSR API (now only for vue3).

Comparasion with other CSS-in-JS framework

Main differences between css-render and styled-component, jss or emotion:

It doesn't do the bindings between components and styles. It is more like a style generator with low level mount and unmount API.
It's easier to write like a sass mixin or less mixin.

Examples

Realword Example

Basic Example

$ npm install --save-dev css-render

import CssRender from 'css-render'
/**
 * common js:
 * const { CssRender } = require('css-render')
 */

const {
  c
} = CssRender()

const style = c('body', ({ props }) => ({
  margin: 0,
  backgroundColor: props.backgroundColor
}), [
  c('&.dark', {
    backgroundColor: 'black'
  }),
  c('.container', {
    width: '100%'
  })
])

/** use it as string */
console.log(style.render({ backgroundColor: 'white' }))
/**
 * or mount on document.head. (the following lines only work in the browser.)
 */
style.mount()
// ...
style.unmount()

body {
  margin: 0;
  background-color: white;
}

body.dark {
  background-color: black;
}

body .container {
  width: 100%;
}

BEM Plugin Example

$ npm install --save-dev css-render @css-render/plugin-bem

You can use bem plugin to generate bem CSS like this:

import CssRender from 'css-render'
import bem from '@css-render/plugin-bem'
/**
 * common js:
 * const { CssRender } = require('css-render')
 * const { plugin: bem } = require('@css-render/plugin-bem')
 */

const cssr = CssRender()
const plugin = bem({
  blockPrefix: '.c-'
})
cssr.use(plugin) // bind the plugin with the cssr instance
const {
  cB, cE, cM
} = plugin

const style = cB(
  'container',
  [
    cE(
      'left, right', 
      {
        width: '50%'
      }
    ),
    cM(
      'dark', 
      [
        cE(
          'left, right',
          {
            backgroundColor: 'black'
          }
        )
      ]
    )
  ]
)

/** use it as string */
console.log(style.render())
/**
 * or mount on document.head
 * the following lines only works in browser, don't call them in node.js
 */
style.mount()
// ...
style.unmount()

.c-container .c-container__left, .c-container .c-container__right {
  width: 50%;
}

.c-container.c-container--dark .c-container__left, .c-container.c-container--dark .c-container__right {
  background-color: black;
}

Vue3 SSR

$ npm install --save-dev css-render @css-render/vue3-ssr

To make ssr works, you need to make

import { h, createSSRApp, defineComponent } from 'vue'
import { renderToString } from '@vue/server-renderer'

import { CssRender } from 'css-render'
import { SsrContext, ssrAdapter } from '@css-render/vue3-ssr'

const Child = defineComponent({
  setup () {
    c('div', {
      color: 'red'
    }).mount({
      id: 'mount-id',
      // You need to pass the ssrAdapter to `mount` function
      // to make ssr work.
      // If you want it work with CSR, just set it to undefined
      ssr: ssrAdapter 
    })
  },
  render () {
    return 'Child'
  }
})

const App = defineComponent({
  render () {
    // Wrap the SsrContext at the root of your app
    return h(SsrContext, null, {
      default: () => h(Child)
    })
  }
})

const app = createSSRApp(App)

renderToString(app).then(v => { console.log(v) })

Finally you will find the rendered SSR HTML includes mounted style.