Spike JSS

A simple static render for jss.

Note: This project is in early development, and versioning is a little different. Read this for more details.

Installation

npm install spike-jss -S

Usage

// app.js
const jssPreset = require('jss-preset-default')

new Jss({
  files: 'assets/jss/*.js',
  output: 'css/main.css',
  options: jssPreset()
})

With this config, you get your jss files processed and the stylesheet output to the path as specified. In order to access the classes, you will need to require or import the jss files into a component - they will be imported as a jss stylesheet by default. Here's an example with react:

import {classes} from '../jss/hero'

export default () => {
  return (<p className={classes.hello}>Hello world!</p>)
}

If you need to use interactive styles through jss, the currently recommended method by jss is to regenerate styles from your jss and remove the server-rendered styles rather than rehydrating existing styles. You can do this as you normally would in jss, and you can get your jss source by importing rules from the module.

import jss from 'jss'
import {rules} from '../jss/hero'

export default () => {
  const sheet = jss.createStyleSheet(rules)
  sheet.attach()
  return (<p className={sheet.classes.hello}>Hello world!</p>)
}

Extractions & Critical CSS

NOTE: This feature hasn't been built yet, but will be soon!

This plugin is built with the ability to extract critical css in any way you'd like, but it won't do it for you using phantomjs etc because everyone has a different size screen and as such this is a very imprecise method. You can do something like this to extract chunks of css:

// app.js
new Jss({
  files: 'assets/jss/*.js',
  output: 'css/main.css',
  extract: {
    layout: 'assets/jss/critical/*.js'
    index: ['assets/jss/hero.js', 'assets/jss/index-slider.js'],
    about: 'assets/jss/special-about-component.js'
  },
  addDataTo: locals // optional
})

You can find the extracted css chunks on your locals object under _extractedCss followed by the key you used for the extraction chunk. So for example you might do this in your layout:

html
  head
    title My cool demo page
    style {{ _extractedCss.layout }}
    block css
    script loadCss('/css/main.css')
  body
    nav
      a(href='/') Home
      a(href='/about') About
    block content

And this in the index file (sugarml):

block css
  style {{ _extractedCss.index }}
block content
  p hello world!

This would ensure that only your critical css for each page is rendered in the head. For more details on critical CSS stuff, see this article. Also note that the perf gain from using critical css is very small and absolutely not worth it until you have exhausted all other performance optimizations, especially images and javascript.

License & Contributing

• Details on the license can be found here
• Details on running tests and contributing can be found here