styled-jsx

Full, scoped and component-friendly CSS support for JSX (rendered on the server or the client).

Code and docs are for v2 which we highly recommend you to try. Looking for styled-jsx v1? Switch to the v1 branch.

For an overview about the features and tradeoffs of styled-jsx you may want to take a look at this presentation.

Getting started
Configuration options
Features
How It Works
- Why It Works Like This
Targeting The Root
Keeping CSS in separate files
Styles outside of components
Global styles
- One-off global selectors
Dynamic styles
Constants
Server-Side Rendering
- styled-jsx/server
CSS Preprocessing via Plugins
- Plugin options
- Example plugins
FAQ
Syntax Highlighting

Getting started

Firstly, install the package:

npm install --save styled-jsx

Next, add styled-jsx/babel to plugins in your babel configuration:

{
  "plugins": [
    "styled-jsx/babel"
  ]
}

Now add <style jsx> to your code and fill it with CSS:

export default () => (
  <div>
    <p>only this paragraph will get the style :)</p>

    { /* you can include <Component />s here that include
         other <p>s that don't get unexpected styles! */ }

    <style jsx>{`
      p {
        color: red;
      }
    `}</style>
  </div>
)

Configuration options

The following are optional settings for the babel plugin.

`optimizeForSpeed`

Blazing fast and optimized CSS rules injection system based on the CSSOM APIs.

{
  "plugins": [
    ["styled-jsx/babel", { "optimizeForSpeed": true }]
  ]
}

When in production* this mode is automatically enabled.
Beware that when using this option source maps cannot be generated and styles cannot be edited via the devtools.

* process.env.NODE_ENV === 'production'

`sourceMaps`

Generates source maps (default: false)

`vendorPrefixes`

Turn on/off automatic vendor prefixing (default: true)

Features

Full CSS support, no tradeoffs in power
Runtime size of just 3kb (gzipped, from 12kb)
Complete isolation: Selectors, animations, keyframes
Built-in CSS vendor prefixing
Very fast, minimal and efficient transpilation (see below)
High-performance runtime-CSS-injection when not server-rendering
Future-proof: Equivalent to server-renderable "Shadow CSS"
Source maps support
Dynamic styles and themes support *new
CSS Preprocessing via Plugins *new

How It Works

The example above transpiles to the following:

import _JSXStyle from 'styled-jsx/style'

export default () => (
  <div className='jsx-123'>
    <p className='jsx-123'>only this paragraph will get the style :)</p>
    <_JSXStyle styleId='123' css={`p.jsx-123 {color: red;}`} />
  </div>
)

Why It Works Like This

Unique classnames give us style encapsulation and _JSXStyle is heavily optimized for:

Injecting styles upon render
Only injecting a certain component's style once (even if the component is included multiple times)
Removing unused styles
Keeping track of styles for server-side rendering

Targeting The Root

Notice that the outer <div> from the example above also gets a jsx-123 classname. We do this so that you can target the "root" element, in the same manner that :host works with Shadow DOM.

If you want to target only the host, we suggest you use a class:

export default () => (
  <div className="root">
    <style jsx>{`
      .root {
        color: green;
      }
    `}</style>
  </div>
)

Keeping CSS in separate files

Styles can be defined in separate JavaScript modules by tagging with css any template literal that contain CSS.

css must be imported from styled-jsx/css:

/* styles.js */
import css from 'styled-jsx/css'

export const button = css`button { color: hotpink; }`
export default css`div { color: green; }`

imported as regular strings:

import styles, { button } from './styles'

export default () => (
  <div>
    <button>styled-jsx</button>
    <style jsx>{styles}</style>
    <style jsx>{button}</style>
  </div>
)

Styles are automatically scoped but you can also be consumed as globals.

N.B. Dynamic styles cannot be used in external styles.

We also support CommonJS exports but you can only export one string per module:

module.exports = css`div { color: green; }`

// the following won't work
// module.exports = { styles: css`div { color: green; }` }

Styles outside of components

The css tag from styled-jsx/css can be also used to define styles in your components files but outside of the component itself. This might help with keeping render methods smaller.

import css from 'styled-jsx/css'

export default () => (
  <div>
    <button>styled-jsx</button>
    <style jsx>{button}</style>
  </div>
)

const button = css`button { color: hotpink; }`

Like in externals styles css doesn't work with dynamic styles. If you have dynamic parts you might want to place them inline inside of your component using a regular <style jsx> element.

Global styles

To skip scoping entirely, you can make the global-ness of your styles explicit by adding global.

export default () => (
  <div>
    <style jsx global>{`
      body {
        background: red
      }
    `}</style>
  </div>
)

The advantage of using this over <style> is twofold: no need to use dangerouslySetInnerHTML to avoid escaping issues with CSS and take advantage of styled-jsx's de-duping system to avoid the global styles being inserted multiple times.

One-off global selectors

Sometimes it's useful to skip selectors scoping. In order to get a one-off global selector we support :global(), inspired by css-modules.

This is very useful in order to, for example, generate a global class that you can pass to 3rd-party components. For example, to style react-select which supports passing a custom class via optionClassName:

import Select from 'react-select'
export default () => (
  <div>
    <Select optionClassName="react-select" />

    <style jsx>{`
      /* "div" will be prefixed, but ".react-select" won't */

      div :global(.react-select) {
        color: red
      }
    `}</style>
  </div>
)

Dynamic styles

To make a component's visual representation customizable from the outside world there are three options.

Via interpolated dynamic props

Any value that comes from the component's render method scope is treated as dynamic. This makes it possible to use props and state for example.

const Button = (props) => (
  <button>
     { props.children }
     <style jsx>{`
        button {
          padding: ${ 'large' in props ? '50' : '20' }px;
          background: ${props.theme.background};
          color: #999;
          display: inline-block;
          font-size: 1em;
        }
     `}</style>
  </button>
)

New styles' injection is optimized to perform well at runtime.

That said when your CSS is mostly static we recommend to split it up in static and dynamic styles and use two separate style tags so that, when changing, only the dynamic parts are recomputed/rendered.

const Button = (props) => (
  <button>
     { props.children }
     <style jsx>{`
        button {
          color: #999;
          display: inline-block;
          font-size: 2em;
        }
     `}</style>
     <style jsx>{`
        button {
          padding: ${ 'large' in props ? '50' : '20' }px;
          background: ${props.theme.background};
        }
     `}</style>
  </button>
)

Via `className` toggling

The second option is to pass properties that toggle class names.

const Button = (props) => (
  <button className={ 'large' in props && 'large' }>
     { props.children }
     <style jsx>{`
        button {
          padding: 20px;
          background: #eee;
          color: #999
        }
        .large {
          padding: 50px
        }
     `}</style>
  </button>
)

Then you would use this component as either <Button>Hi</Button> or <Button large>Big</Button>.

Via inline `style`

*best for animations

Imagine that you wanted to make the padding in the button above completely customizable. You can override the CSS you configure via inline-styles:

const Button = ({ padding, children }) => (
  <button style={{ padding }}>
     { children }
     <style jsx>{`
        button {
          padding: 20px;
          background: #eee;
          color: #999
        }
     `}</style>
  </button>
)

In this example, the padding defaults to the one set in <style> (20), but the user can pass a custom one via <Button padding={30}>.

Constants

It is possible to use constants like so:

import { colors, spacing } from '../theme'
import { invertColor } from '../theme/utils'

const Button = ({ children }) => (
  <button>
     { children }
     <style jsx>{`
        button {
          padding: ${ spacing.medium };
          background: ${ colors.primary };
          color: ${ invertColor(colors.primary) };
        }
     `}</style>
  </button>
)

Please keep in mind that constants defined outside of the component scope are treated as static styles.

Server-Side Rendering

`styled-jsx/server`

The main export flushes your styles to an array of React.Element:

import React from 'react'
import ReactDOM from 'react-dom/server'
import flush from 'styled-jsx/server'
import App from './app'

export default (req, res) => {
  const app = ReactDOM.renderToString(<App />)
  const styles = flush()
  const html = ReactDOM.renderToStaticMarkup(<html>
    <head>{ styles }</head>
    <body>
      <div id="root" dangerouslySetInnerHTML={{__html: app}} />
    </body>
  </html>)
  res.end('<!doctype html>' + html)
}

We also expose flushToHTML to return generated HTML:

import React from 'react'
import ReactDOM from 'react-dom/server'
import { flushToHTML } from 'styled-jsx/server'
import App from './app'

export default (req, res) => {
  const app = ReactDOM.renderToString(<App />)
  const styles = flushToHTML()
  const html = `<!doctype html>
    <html>
      <head>${styles}</head>
      <body>
        <div id="root">${app}</div>
      </body>
    </html>`
  res.end(html)
}

It's paramount that you use one of these two functions so that the generated styles can be diffed when the client loads and duplicate styles are avoided.

CSS Preprocessing via Plugins

Styles can be preprocessed via plugins.

Plugins are regular JavaScript modules that export a simple function with the following signature:

(css: string, options: Object) => string

Basically they accept a CSS string in input, optionally modify it and finally return it.

Plugins make it possible to use popular preprocessors like SASS, Less, Stylus, PostCSS or apply custom transformations to the styles at compile time.

To register a plugin add an option plugins for styled-jsx/babel to your .babelrc. plugins must be an array of module names or full paths for local plugins.

{
  "plugins": [
    [
      "styled-jsx/babel",
      { "plugins": ["my-styled-jsx-plugin-package", "/full/path/to/local/plugin"] }
    ]
  ]
}

Instructions to integrate with Next.js

In order to register styled-jsx plugins in a Next.js app you need to create a custom .babelrc file:

{
  "presets": [
    [
      "next/babel",
      {
        "styled-jsx": {
          "plugins": [
            "styled-jsx-plugin-postcss"
          ]
        }
      }
    ]
  ]
}

This is a fairly new feature so make sure that you using a version of Next.js that supports passing options to styled-jsx.

Plugins are applied in definition order left to right before styles are scoped.

In order to resolve local plugins paths you can use NodeJS' require.resolve.

N.B. when applying the plugins styled-jsx replaces template literals expressions with placeholders because otherwise CSS parsers would get invalid CSS E.g.

/* `ExprNumber` is a number */
%%styled-jsx-placeholder-ExprNumber%%

Plugins won't transform expressions (eg. dynamic styles).

When publishing a plugin you may want to add the keywords: styled-jsx and styled-jsx-plugin. We also encourage you to use the following naming convention for your plugins:

styled-jsx-plugin-<your-plugin-name>

Plugin options

Users can set plugin options by registering a plugin as an array that contains the plugin path and an options object.

{
  "plugins": [
    [
      "styled-jsx/babel",
      {
        "plugins": [
          ["my-styled-jsx-plugin-package", { "exampleOption":  true }]
        ],
        "sourceMaps": true
      }
    ]
  ]
}

Each plugin receives a options object as second argument which contains the babel and user options:

(css, options) => { /* ... */ }

The options object has the following shape:

{
  // user options go here
  // eg. exampleOption: true

  // babel options
  babel: {
    sourceMaps: boolean,
    vendorPrefixes: boolean,
    isGlobal: boolean,
    filename: ?string, // defined only when the filename option is passed to Babel, such as when using Babel CLI or Webpack
    location: { // the original location of the CSS block in the JavaScript file
      start: {
        line: number,
        column: number,
      },
      end: {
        line: number,
        column: number,
      }
    }
  }
}

Example plugins

The following plugins are proof of concepts/sample:

FAQ

Warning: unknown `jsx` prop on <style> tag

If you get this warning it means that your styles were not compiled by styled-jsx.

Please take a look at your setup and make sure that everything is correct and that the styled-jsx transformation is ran by Babel.

Can I return an array of components when using React 16?

No, this feature is not supported. However we support React Fragments, which are available in React 16.2.0 and above.

const StyledImage = ({ src, alt = '' }) => (
  <React.Fragment>
   <img src={src} alt={alt} />
   <style jsx>{`img { max-width: 100% }`}</style>
  </React.Fragment>
)

Styling third parties / child components from the parent

When the component accepts a className (or ad-hoc) prop that you can use to style those components then you can generate scoped styles locally in the parent component and resolve them to get a className and the actual scoped styles like so:

import Link from 'react-router-dom' // component to style

// Generate a `scope` fragment and resolve it
const scoped = resolveScopedStyles(
  <scope>
    <style jsx>{'.link { color: green }'}</style>
  </scope>
)

// Your component that uses Link
export default ({ children }) => (
  <div>
    {children}

    {/* use the scoped className */}
    <Link to="/about" className={`link ${scoped.className}`}>
      About
    </Link>

    {/* apply the scoped styles */}
    {scoped.styles}
  </div>
)

resolveScopedStyles looks like this:

function resolveScopedStyles(scope) {
  return {
    className: scope.props.className,
    styles: scope.props.children
  }
}

When the component doesn't accept any className or doesn't expose any API to customize the component, then you only option is to use :global() styles:

export default () => (
  <div>
    <ExternalComponent />

    <style jsx>{`
      /* "div" will be prefixed, but ".nested-element" won't */

      div > :global(.nested-element) {
        color: red
      }
    `}</style>
  </div>
)

Build a component library with styled-jsx

There's an article explaining how to bundle React components with Rollup and styled-jsx as an external dependency.

Syntax Highlighting

When working with template literals a common drawback is missing syntax highlighting. The following editors currently have support for highlighting CSS inside <style jsx> elements.

If you have a solution for an editor not on the list please open a PR and let us now.

Atom

The language-babel package for the Atom editor has an option to extend the grammar for JavaScript tagged template literals.

After installing the package add the code below to the appropriate settings entry. In a few moments you should be blessed with proper CSS syntax highlighting. (source)

"(?<=<style jsx>{)|(?<=<style jsx global>{)":source.css.styled

Webstorm/Idea

The IDE let you inject any language in place with Inject language or reference in an Intention Actions (default alt+enter). Simply perform the action in the string template and select CSS. You get full CSS highlighting and autocompletion and it will last until you close the IDE.

Additionally you can use language injection comments to enable all the IDE language features indefinitely using the language comment style:

import { colors, spacing } from '../theme'
import { invertColor } from '../theme/utils'

const Button = ({ children }) => (
  <button>
     { children }

     { /*language=CSS*/ }
     <style jsx>{`
        button {
          padding: ${ spacing.medium };
          background: ${ colors.primary };
          color: ${ invertColor(colors.primary) };
        }
     `}</style>
  </button>
)

Emmet

If you're using Emmet you can add the following snippet to ~/emmet/snippets-styledjsx.json This will allow you to expand style-jsx to a styled-jsx block.

{
 "html": {
   "snippets": {
     "style-jsx": "<style jsx>{`\n\t$1\n`}</style>"
   }
 }
}

Syntax Highlighting Visual Studio Code Extension

Launch VS Code Quick Open (⌘+P), paste the following command, and press enter.

ext install vscode-styled-jsx

Autocomplete Visual Studio Code Extension

Launch VS Code Quick Open (⌘+P), paste the following command, and press enter.

ext install vscode-styled-jsx-languageserver

Vim

Install vim-styled-jsx with your plugin manager of choice.

ESLint

If you're using eslint-plugin-import, the css import will generate errors, being that it's a "magic" import (not listed in package.json). To avoid these, simply add the following line to your eslint configuration:

"settings": {"import/core-modules": ["styled-jsx/css"] }

Credits

Pedram Emrouznejad (rijs) suggested attribute selectors over my initial class prefixing idea.
Sunil Pai (glamor) inspired the use of murmurhash2 (minimal and fast hashing) and an efficient style injection logic.
Sultan Tarimo built stylis.js, a super fast and tiny CSS parser and compiler.
Max Stoiber (styled-components) proved the value of retaining the familiarity of CSS syntax and pointed me to the very efficient stylis compiler (which we forked to very efficiently append attribute selectors to the user's css)
Yehuda Katz (ember) convinced me on Twitter to transpile CSS as an alternative to CSS-in-JS.
Evan You (vuejs) discussed his Vue.js CSS transformation with me.
Henry Zhu (babel) helpfully pointed me to some important areas of the babel plugin API.

Authors

Guillermo Rauch (@rauchg) - ▲ZEIT
Naoyuki Kanezawa (@nkzawa) - ▲ZEIT
Giuseppe Gurgone (@giuseppegurgone)

kevva / styled-jsx Goto Github PK

styled-jsx's Introduction