@huozhi/styled-jsx

v5.0.4-alpha.5

Published

2 years ago

Full CSS support for JSX without compromises

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styled-jsx

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

Code and docs are for v3 which we highly recommend you to try. Looking for styled-jsx v2? Switch to the v2 branch.

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)

`styleModule`

Module that the transpiled files should import (default: styled-jsx/style)

`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
CSS Preprocessing via Plugins

Using in Next.js

Next.js automatically configures styled-jsx with babel or swc, you don't have to configure it manually.

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 id="123">{`p.jsx-123 {color: red;}`}</_JSXStyle>
  </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>
)

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 v5 introduced StyledRegistry component and useStyleRegistry hook to let you scope styles rendering in each SSR render to keep concurrent-safe.

registry.styles() will return the array of react components for style tags.
registry.flush() can clean the existing styles in the registry, it's optional for SSR when you have a standalone registry for each SSR render.

Next.js 12 integrates with styled-jsx v5 and manages the registry for you.

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

function Styles() {
  const registry = useStyleRegistry()
  const styles = registry.styles()
  return <>{styles}</>
}

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

There's also a new API createStyleRegistry that is introduced when you have to create a registry manually. In this way you can operate the registry yourself to extract the rendered styles (registry.styles()) or flush them out (registry.flush()).

const registry = createStyleRegistry()
const styles = registry.styles() // access styles

function Page() {
  return (
    <StyleRegistry registry={registry}>
      <App />
    </StyleRegistry>
  )
}

By default <StyleRegistry /> will use the registry from root top StyleRegistry, which means there's only one registry in the react tree.

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.

Content Security Policy

Strict CSP is supported.

You should generate a nonce per request.

import nanoid from 'nanoid'

const nonce = Buffer.from(nanoid()).toString('base64') //ex: N2M0MDhkN2EtMmRkYi00MTExLWFhM2YtNDhkNTc4NGJhMjA3

You must then pass a nonce to registry.styles({ nonce }) and set a <meta property="csp-nonce" content={nonce} /> tag.

Your CSP policy must share the same nonce as well (the header nonce needs to match the html nonce and remain unpredictable). Content-Security-Policy: default-src 'self'; style-src 'self' 'nonce-N2M0MDhkN2EtMmRkYi00MTExLWFhM2YtNDhkNTc4NGJhMjA3';

External CSS and styles outside of the component

In styled-jsx styles can be defined outside of the component's render method or in separate JavaScript modules using the styled-jsx/css library. styled-jsx/css exports three tags that can be used to tag your styles:

css, the default export, to define scoped styles.
css.global to define global styles.
css.resolve to define scoped styles that resolve to the scoped className and a styles element.

External styles

In an external file:

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

// Scoped styles
export const button = css`
  button {
    color: hotpink;
  }
`

// Global styles
export const body = css.global`body { margin: 0; }`

// Resolved styles
export const link = css.resolve`a { color: green; }`
// link.className -> scoped className to apply to `a` elements e.g. jsx-123
// link.styles -> styles element to render inside of your component

// Works also with default exports
export default css`
  div {
    color: green;
  }
`

You can then import and use those styles:

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

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

N.B. All the tags except for resolve don't support dynamic styles.

resolve and global can also be imported individually:

import { resolve } from 'styled-jsx/css'
import { global } from 'styled-jsx/css'

If you use Prettier we recommend you to use the default css export syntax since the tool doesn't support named imports.

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.

The `resolve` tag

The resolve tag from styled-jsx/css can be used when you need to scope some CSS - for example, if you need to style nested components from the parent, such as the Link component in the example below.

It works by returning the generated scoped className and related styles.

import React from 'react'
import Link from 'some-library'

import css from 'styled-jsx/css'

const { className, styles } = css.resolve`
  a { color: green }
`

export default () => (
  <div>
    {/* use the className */}
    <Link className={className}>About</Link>

    {/* render the styles for it */}
    {styles}
  </div>
)

The resolve tag also supports dynamic styles, via template string interpolation:

import React from 'react'
import css from 'styled-jsx/css'

function getLinkStyles(color) {
  return css.resolve`
    a { color: ${color} }
  `
}

export default props => {
  const { className, styles } = getLinkStyles(props.theme.color)

  return (
    <div>
      <Link className={className}>About</Link>
      {styles}
    </div>
  )
}

Using `resolve` as a Babel macro

If you can't (or would rather not) make changes to your .babelrc, the resolve tag can be used as a Babel macro, thanks to the babel-plugin-macros system.

To set this up, first of all, install styled-jsx and babel-plugin-macros:

npm i --save styled-jsx
npm i --save-dev babel-plugin-macros

Next, add babel-plugin-macros to your Babel configuration:

{
  "plugins": ["babel-plugin-macros"]
}

You can then use resolve by importing it from styled-jsx/macro.

import css from 'styled-jsx/macro'

const { className, styles } = css.resolve`
  a { color: green }
`

export default () => (
  <div>
    <Link className={className}>About</Link>
    {styles}
  </div>
)

Usage with `create-react-app`

Create React App comes with babel-plugin-macros already installed, so the only thing that needs to be done is to install styled-jsx:

npm i --save styled-jsx

Then resolve can be imported from styled-jsx/macro and used the same way as in the example in the Using resolve as a Babel macro section above.

Styles in regular CSS files

styled-jsx v3 comes with a webpack loader that lets you write styles in regular css files and consume them in React.

import styles from '../components/button/styles.css'

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

To consume the styles in your component you can import them from your CSS file and render them using a <style jsx> tag. Remember to add the global prop if you want your styles to be global.

To use this feature you need to register the loader in your webpack config file, before babel-loader which will then transpile the styles via styled-jsx/babel

config: {
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [
          {
            loader: require('styled-jsx/webpack').loader,
            options: {
              type: 'scoped'
            }
          }
        ]
      }
    ]
  }
}

The plugin accepts a type option to configure whether the styles should be scoped, global or resolve (see above). By default its values is set to scoped. type can also be a function which takes the fileName and the fileNameQuery that is being transpiled and must return a valid type.

type validTypes = 'scoped' | 'global' | 'resolve'
type fileName = string
type Options = {|
  type: validTypes | ((fileName, options) => validTypes)
|}

import styles from './styles.css?type=global'

// webpack
config: {
  module: {
    rules: [
      {
        test: /\.css$/,
        use: [
          {
            loader: require('styled-jsx/webpack').loader,
            options: {
              type: (fileName, options) => options.query.type || 'scoped'
            }
          }
        ]
      }
    ]
  }
}

The type can also be set per individual CSS file via CSS comment:

/* @styled-jsx=scoped */

button {
  color: red;
}

The CSS comment option will override the one in the webpack configuration only for this specific file.

Next.js

Example of next.config.js to integrate styled-jsx/webpack:

module.exports = {
  webpack: (config, { defaultLoaders }) => {
    config.module.rules.push({
      test: /\.css$/,
      use: [
        defaultLoaders.babel,
        {
          loader: require('styled-jsx/webpack').loader,
          options: {
            type: 'scoped'
          }
        }
      ]
    })

    return config
  }
}

CSS Preprocessing via Plugins

Styles can be preprocessed via plugins.

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

function plugin(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"
        ]
      }
    ]
  ]
}

{
  "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:

Rendering in tests

If you're using a tool such as Enzyme, you might want to avoid compiling your styles in test renders. In general, styled-jsx artifacts like jsx-123 classnames and vendor prefixing are not direct concerns of your component, and they generate a lot of snapshot noise.

One option is to exclude the styled-jsx/babel plugin from the test environment using env in your Babel config (see Config Merging options).

But this can cause noise in your terminal output when rendering:

   console.error node_modules/react-dom/cjs/react-dom.development.js:527
      Warning: Received `true` for a non-boolean attribute `jsx`.

The styled-jsx/babel-test solves this problem. It simply strips jsx attributes from all <style> tags. Be sure to target each environment with the appropriate plugin:

{
  "env": {
    "production": {
      "plugins": ["styled-jsx/babel"]
    },
    "development": {
      "plugins": ["styled-jsx/babel"]
    },
    "test": {
      "plugins": ["styled-jsx/babel-test"]
    }
  }
}

styled-jsx/css in tests

When using styled-jsx/babel-test, styled-jsx/css throws the following error:

styled-jsx/css: if you are getting this error it means that your `css` tagged template literals were not transpiled.

to solve this issue you need to mock styled-jsx/css. You can find a guide at the following link https://kevinjalbert.com/jest-snapshots-reducing-styled-jsx-noise/

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 as a way to allow customizations then you can use the resolve tag from styled-jsx/css.

When the component doesn't accept any className or doesn't expose any API to customize the component, then your 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>
)

Please keep in mind that :global() styles will affect the entire subtree, so in many cases you may want to be careful and use the children (direct descendant) selector >.

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

babel-language settings entry

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 Divlo.vscode-styled-jsx-syntax

If you use Stylus instead of plain CSS, install vscode-styled-jsx-stylus or paste the command below.

ext install vscode-styled-jsx-stylus

Autocomplete Visual Studio Code Extension

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

ext install Divlo.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"] }

TypeScript

If you're using TypeScript, then in order to allow <style jsx> tags to be properly understood by it, create a file named "styled-jsx.d.ts" anywhere within your project containing the following, or add this line to the top of any single existing .ts file within your project:

/// <reference types="styled-jsx" />

If you're using babel to transform styled-jsx code with TypeScript, you need to specify "jsx": "preserve" in your tsconfig.json to keep the original JSX and let babel parse and transform with styled-jsx babel plugin.

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) - ▲Vercel
Naoyuki Kanezawa (@nkzawa) - ▲Vercel
Giuseppe Gurgone (@giuseppegurgone)