@vanilla-extract/css

What is @vanilla-extract/css?

@vanilla-extract/css is a zero-runtime CSS-in-TypeScript library. It allows you to write type-safe, themeable, and modular CSS using TypeScript. The library compiles your styles to static CSS at build time, ensuring no runtime overhead.

What are @vanilla-extract/css's main functionalities?

Creating Styles

This feature allows you to create CSS styles using TypeScript. The `style` function is used to define a class with various CSS properties.

import { style } from '@vanilla-extract/css';

const buttonStyle = style({
  backgroundColor: 'blue',
  color: 'white',
  padding: '10px 20px',
  borderRadius: '5px',
  ':hover': {
    backgroundColor: 'darkblue'
  }
});

Theming

Theming allows you to create and use design tokens in your styles. The `createTheme` function generates a theme class and variables that can be used in your styles.

import { createTheme, style } from '@vanilla-extract/css';

const [themeClass, vars] = createTheme({
  color: {
    primary: 'blue',
    secondary: 'green'
  },
  font: {
    body: 'Arial, sans-serif'
  }
});

const themedStyle = style({
  backgroundColor: vars.color.primary,
  color: vars.color.secondary,
  fontFamily: vars.font.body
});

Composition

Composition allows you to combine multiple styles into one. The `composeStyles` function is used to merge multiple style classes into a single class.

import { style, composeStyles } from '@vanilla-extract/css';

const baseStyle = style({
  padding: '10px',
  borderRadius: '5px'
});

const primaryButton = style({
  backgroundColor: 'blue',
  color: 'white'
});

const composedStyle = composeStyles(baseStyle, primaryButton);

Other packages similar to @vanilla-extract/css

styled-components

styled-components is a popular library for writing CSS-in-JS. It allows you to use ES6 and CSS to style your components. Unlike @vanilla-extract/css, styled-components has a runtime dependency and supports dynamic styling.

emotion

Emotion is a performant and flexible CSS-in-JS library. It provides both a styled API similar to styled-components and a low-level CSS API. Emotion also has runtime dependencies but offers more flexibility in terms of styling approaches.

linaria

Linaria is a zero-runtime CSS-in-JS library similar to @vanilla-extract/css. It allows you to write CSS in JavaScript and extracts it to static CSS files at build time. Linaria focuses on performance and type safety, much like @vanilla-extract/css.

README

🧁 vanilla-extract

Zero-runtime Stylesheets-in-TypeScript.

Write your styles in TypeScript (or JavaScript) with locally scoped class names and CSS Variables, then generate static CSS files at build time.

Basically, it’s “CSS Modules-in-TypeScript” but with scoped CSS Variables + heaps more.

🔥   All styles generated at build time — just like Sass, Less, etc.

✨   Minimal abstraction over standard CSS.

🦄   Works with any front-end framework — or even without one.

🌳   Locally scoped class names — just like CSS Modules.

🚀   Locally scoped CSS Variables, @keyframes and @font-face rules.

🎨   High-level theme system with support for simultaneous themes. No globals!

🛠   Utils for generating variable-based calc expressions.

💪   Type-safe styles via CSSType.

🏃‍♂️   Optional runtime version for development and testing.

🙈   Optional API for dynamic runtime theming.

---

🖥   Try it out for yourself in CodeSandbox.

---

Write your styles in .css.ts files.

// styles.css.ts

import { createTheme, style } from '@vanilla-extract/css';

export const [themeClass, vars] = createTheme({
  color: {
    brand: 'blue'
  },
  font: {
    body: 'arial'
  }
});

export const exampleStyle = style({
  backgroundColor: vars.color.brand,
  fontFamily: vars.font.body,
  color: 'white',
  padding: 10
});

💡 Once you've configured your build tooling, these .css.ts files will be evaluated at build time. None of the code in these files will be included in your final bundle. Think of it as using TypeScript as your preprocessor instead of Sass, Less, etc.

Then consume them in your markup.

// app.ts

import { themeClass, exampleStyle } from './styles.css.ts';

document.write(`
  <section class="${themeClass}">
    <h1 class="${exampleStyle}">Hello world!</h1>
  </section>
`);

---

Want to work at a higher level while maximising style re-use? Check out 🍨 Sprinkles, our official zero-runtime atomic CSS framework, built on top of vanilla-extract.

---

• Setup
  • webpack
  • esbuild
  • Vite
  • Next.js
  • Gatsby
  • Rollup
  • Test environments
  • Configuration
    • identifiers
    • esbuildOptions
• Styling API
  • style
  • styleVariants
  • globalStyle
  • createTheme
  • createGlobalTheme
  • createThemeContract
  • createGlobalThemeContract
  • assignVars
  • createVar
  • fallbackVar
  • fontFace
  • globalFontFace
  • keyframes
  • globalKeyframes
• Recipes API
  • recipe
• Dynamic API
  • assignInlineVars
  • setElementVars
• Utility functions
  • calc
• Thanks
• License

---

Setup

There are currently a few integrations to choose from.

webpack

1. Install the dependencies.

npm install @vanilla-extract/css @vanilla-extract/webpack-plugin

1. Add the webpack plugin.

💡 This plugin accepts an optional configuration object.

const { VanillaExtractPlugin } = require('@vanilla-extract/webpack-plugin');

module.exports = {
  plugins: [new VanillaExtractPlugin()],
};

You'll need to ensure you're handling CSS files in your webpack config.

For example:

const { VanillaExtractPlugin } = require('@vanilla-extract/webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = {
  plugins: [
    new VanillaExtractPlugin(),
    new MiniCssExtractPlugin()
  ],
  module: {
    rules: [
      {
        test: /\.vanilla\.css$/i, // Targets only CSS files generated by vanilla-extract
        use: [
          MiniCssExtractPlugin.loader,
          {
            loader: require.resolve('css-loader'),
            options: {
              url: false // Required as image imports should be handled via JS/TS import statements
            }
          }
        ]
      }
    ]
  }
};

1. If you'd like automatic debuggable identifiers, you can add the Babel plugin.

$ npm install @vanilla-extract/babel-plugin

{
  "plugins": ["@vanilla-extract/babel-plugin"]
}

esbuild

1. Install the dependencies.

npm install @vanilla-extract/css @vanilla-extract/esbuild-plugin

1. Add the esbuild plugin to your build script.

💡 This plugin accepts an optional configuration object.

const { vanillaExtractPlugin } = require('@vanilla-extract/esbuild-plugin');

require('esbuild').build({
  entryPoints: ['app.ts'],
  bundle: true,
  plugins: [vanillaExtractPlugin()],
  outfile: 'out.js',
}).catch(() => process.exit(1))

Please note: There are currently no automatic readable class names during development. However, you can still manually provide a debug ID as the last argument to functions that generate scoped styles, e.g. export const className = style({ ... }, 'className');

1. Process CSS

As esbuild currently doesn't have a way to process the CSS generated by vanilla-extract, you can optionally use the processCss option.

For example, to run autoprefixer over the generated CSS.

const {
  vanillaExtractPlugin
} = require('@vanilla-extract/esbuild-plugin');
const postcss = require('postcss');
const autoprefixer = require('autoprefixer');

async function processCss(css) {
  const result = await postcss([autoprefixer]).process(
    css,
    {
      from: undefined /* suppress source map warning */
    }
  );

  return result.css;
}

require('esbuild')
  .build({
    entryPoints: ['app.ts'],
    bundle: true,
    plugins: [
      vanillaExtractPlugin({
        processCss
      })
    ],
    outfile: 'out.js'
  })
  .catch(() => process.exit(1));

Vite

1. Install the dependencies.

npm install @vanilla-extract/css @vanilla-extract/vite-plugin

1. Add the Vite plugin to your Vite config.

💡 This plugin accepts an optional configuration object.

import { vanillaExtractPlugin } from '@vanilla-extract/vite-plugin';

// vite.config.js
export default {
  plugins: [vanillaExtractPlugin()]
}

Please note: There are currently no automatic readable class names during development. However, you can still manually provide a debug ID as the last argument to functions that generate scoped styles, e.g. export const className = style({ ... }, 'className');

Next.js

1. Install the dependencies.

npm install @vanilla-extract/css @vanilla-extract/babel-plugin @vanilla-extract/next-plugin

1. If you don't have a next.config.js file in the root of your project, create one. Add the Next.js plugin to your next.config.js file.

💡 This plugin accepts an optional configuration object.

const {
  createVanillaExtractPlugin
} = require('@vanilla-extract/next-plugin');
const withVanillaExtract = createVanillaExtractPlugin();

/** @type {import('next').NextConfig} */
const nextConfig = {};

module.exports = withVanillaExtract(nextConfig);

If required, this plugin can be composed with other plugins.

const {
  createVanillaExtractPlugin
} = require('@vanilla-extract/next-plugin');
const withVanillaExtract = createVanillaExtractPlugin();

const withMDX = require('@next/mdx')({
  extension: /\.mdx$/
});

/** @type {import('next').NextConfig} */
const nextConfig = {};

module.exports = withVanillaExtract(withMDX(nextConfig));

1. (Optional) If you want to automatically generate debug IDs during development, you can add the Babel plugin. Note that this step will cause Next.js to switch from SWC to Babel, increasing build times. This may or may not be an issue depending on the size of your project.

Note: While optional for Next.js, the Babel plugin is still required when trying to run .css.ts files in Node for unit testing since the files are no longer being processed by a bundler.

If you don't have a .babelrc file in the root of your project, create one. Add the Babel plugin to your .babelrc file, ensuring that you're also including "next/babel" in your presets array.

{
  "presets": ["next/babel"],
  "plugins": ["@vanilla-extract/babel-plugin"]
}

Gatsby

To add to your Gatsby site, use the gatsby-plugin-vanilla-extract plugin.

Rollup

Note: This option is useful for library development but not suitable for application bundles. Rollup has no built-in CSS bundling, so this plugin just outputs styles as individual CSS assets. For applications we instead recommend to use Vite (which itself uses Rollup under the hood but comes with its own CSS bundling).

1. Install the dependencies.

npm install @vanilla-extract/css @vanilla-extract/rollup-plugin

1. Add the Rollup plugin to your Rollup config.

💡 This plugin accepts an optional configuration object.

import { vanillaExtractPlugin } from '@vanilla-extract/rollup-plugin';

// rollup.config.js
export default {
  plugins: [vanillaExtractPlugin()]
}

Test environments

1. Install the dependencies.

$ npm install @vanilla-extract/babel-plugin

1. Add the Babel plugin.

{
  "plugins": ["@vanilla-extract/babel-plugin"]
}

1. Disable runtime styles (Optional)

In testing environments (like jsdom) vanilla-extract will create and insert styles. While this is often desirable, it can be a major slowdown in your tests. If your tests don’t require styles to be available, the disableRuntimeStyles import will disable all style creation.

// setupTests.ts
import '@vanilla-extract/css/disableRuntimeStyles';

Configuration

identifiers

Different formatting of identifiers (e.g. class names, keyframes, CSS Vars, etc) can be configured by selecting from the following options:

• short identifiers are a 7+ character hash. e.g. hnw5tz3
• debug identifiers contain human readable prefixes representing the owning filename and a potential rule level debug name. e.g. myfile_mystyle_hnw5tz3

Each integration will set a default value based on the configuration options passed to the bundler.

esbuildOptions

Only for esbuild, vite and rollup plugins

esbuild is used internally to compile .css.ts files before evaluating them to extract styles. You can pass additional options here to customize that process. Accepts a subset of esbuild build options (plugins, external, define and loader), see https://esbuild.github.io/api/#build-api.

---

Styling API

🍬 If you're a treat user, check out our migration guide.

style

Creates styles attached to a locally scoped class name.

import { style } from '@vanilla-extract/css';

export const className = style({
  display: 'flex'
});

CSS Variables, simple pseudos, selectors and media/feature queries are all supported.

import { style } from '@vanilla-extract/css';
import { vars } from './vars.css.ts';

export const className = style({
  display: 'flex',
  vars: {
    [vars.localVar]: 'green',
    '--global-variable': 'purple'
  },
  ':hover': {
    color: 'red'
  },
  selectors: {
    '&:nth-child(2n)': {
      background: '#fafafa'
    }
  },
  '@media': {
    'screen and (min-width: 768px)': {
      padding: 10
    }
  },
  '@supports': {
    '(display: grid)': {
      display: 'grid'
    }
  }
});

Selectors can also contain references to other scoped class names.

import { style } from '@vanilla-extract/css';

export const parentClass = style({});

export const childClass = style({
  selectors: {
    [`${parentClass}:focus &`]: {
      background: '#fafafa'
    }
  },
});

💡 To improve maintainability, each style block can only target a single element. To enforce this, all selectors must target the “&” character which is a reference to the current element.

For example, '&:hover:not(:active)' and [`${parentClass} &`] are considered valid, while '& a[href]' and [`& ${childClass}`] are not.

If you want to target another scoped class then it should be defined within the style block of that class instead.

For example, [`& ${childClass}`] is invalid since it doesn’t target “&”, so it should instead be defined in the style block for childClass.

If you want to globally target child nodes within the current element (e.g. '& a[href]'), you should use globalStyle instead.

For fallback styles you may simply pass an array of properties instead of a single prop.

export const exampleStyle = style({
  // in Firefox and IE the "overflow: overlay" will be ignored and the "overflow: auto" will be applied
  overflow: ['auto', 'overlay'],
});

Multiple styles can be composed into a single rule by providing an array of styles.

import { style } from '@vanilla-extract/css';

const base = style({ padding: 12 });

export const primary = style([
  base,
  { background: 'blue' }
]);

export const secondary = style([
  base,
  { background: 'aqua' }
]);

When composed styles are used in selectors, they are assigned an additional class if required so they can be uniquely identified. When selectors are processed internally, the composed classes are removed, only leaving behind the unique identifier classes. This allows you to treat them as if they were a single class within vanilla-extract selectors.

import {
  style,
  globalStyle,
} from '@vanilla-extract/css';

const background = style({ background: 'mintcream' });
const padding = style({ padding: 12 });

export const container = style([background, padding]);

globalStyle(`${container} *`, {
  boxSizing: 'border-box'
});

styleVariants

Creates a collection of named style variants.

import { styleVariants } from '@vanilla-extract/css';

export const variant = styleVariants({
  primary: { background: 'blue' },
  secondary: { background: 'aqua' },
});

💡 This is useful for mapping component props to styles, e.g. <button className={styles.variant[props.variant]}>

Multiple styles can be composed into a single rule by providing an array of styles.

import { styleVariants } from '@vanilla-extract/css';

const base = style({ padding: 12 });

export const variant = styleVariants({
  primary: [base, { background: 'blue' }],
  secondary: [base, { background: 'aqua' }],
});

You can also transform the values by providing a map function as the second argument.

import { styleVariants } from '@vanilla-extract/css';

const base = style({ padding: 12 });

const backgrounds = {
  primary: 'blue',
  secondary: 'aqua'
} as const;

export const variant = styleVariants(
  backgrounds,
  (background) => [base, { background }]
);

globalStyle

Creates styles attached to a global selector.

import { globalStyle } from '@vanilla-extract/css';

globalStyle('html, body', {
  margin: 0
});

Global selectors can also contain references to other scoped class names.

import { style, globalStyle } from '@vanilla-extract/css';

export const parentClass = style({});

globalStyle(`${parentClass} > a`, {
  color: 'pink'
});

createTheme

Creates a locally scoped theme class and a theme contract which can be consumed within your styles.

Ensure this function is called within a .css.ts context, otherwise variable names will be mismatched between files.

// theme.css.ts

import { createTheme } from '@vanilla-extract/css';

export const [themeClass, vars] = createTheme({
  color: {
    brand: 'blue'
  },
  font: {
    body: 'arial'
  }
});

You can create theme variants by passing a theme contract as the first argument to createTheme.

// themes.css.ts

import { createTheme } from '@vanilla-extract/css';

export const [themeA, vars] = createTheme({
  color: {
    brand: 'blue'
  },
  font: {
    body: 'arial'
  }
});

export const themeB = createTheme(vars, {
  color: {
    brand: 'pink'
  },
  font: {
    body: 'comic sans ms'
  }
});

💡 All theme values must be provided or it’s a type error.

createGlobalTheme

Creates a theme attached to a global selector, but with locally scoped variable names.

Ensure this function is called within a .css.ts context, otherwise variable names will be mismatched between files.

// theme.css.ts

import { createGlobalTheme } from '@vanilla-extract/css';

export const vars = createGlobalTheme(':root', {
  color: {
    brand: 'blue'
  },
  font: {
    body: 'arial'
  }
});

💡 All theme values must be provided or it’s a type error.

If you want to implement an existing theme contract, you can pass it as the second argument.

// theme.css.ts

import {
  createThemeContract,
  createGlobalTheme
} from '@vanilla-extract/css';

export const vars = createThemeContract({
  color: {
    brand: null
  },
  font: {
    body: null
  }
});

createGlobalTheme(':root', vars, {
  color: {
    brand: 'blue'
  },
  font: {
    body: 'arial'
  }
});

createThemeContract

Creates a contract of locally scoped variable names for themes to implement.

Ensure this function is called within a .css.ts context, otherwise variable names will be mismatched between files.

💡 This is useful if you want to split your themes into different bundles. In this case, your themes would be defined in separate files, but we'll keep this example simple.

// themes.css.ts

import {
  createThemeContract,
  createTheme
} from '@vanilla-extract/css';

export const vars = createThemeContract({
  color: {
    brand: null
  },
  font: {
    body: null
  }
});

export const themeA = createTheme(vars, {
  color: {
    brand: 'blue'
  },
  font: {
    body: 'arial'
  }
});

export const themeB = createTheme(vars, {
  color: {
    brand: 'pink'
  },
  font: {
    body: 'comic sans ms'
  }
});

createGlobalThemeContract

Creates a contract of globally scoped variable names for themes to implement.

💡 This is useful if you want to make your theme contract available to non-JavaScript environments.

// themes.css.ts

import {
  createGlobalThemeContract,
  createGlobalTheme
} from '@vanilla-extract/css';

export const vars = createGlobalThemeContract({
  color: {
    brand: 'color-brand'
  },
  font: {
    body: 'font-body'
  }
});

createGlobalTheme(':root', vars, {
  color: {
    brand: 'blue'
  },
  font: {
    body: 'arial'
  }
});

You can also provide a map function as the second argument which has access to the value and the object path.

For example, you can automatically prefix all variable names.

// themes.css.ts

import { createGlobalThemeContract } from '@vanilla-extract/css';

export const vars = createGlobalThemeContract({
  color: {
    brand: 'color-brand'
  },
  font: {
    body: 'font-body'
  }
}, (value) => `prefix-${value}`);

You can also use the map function to automatically generate names from the object path, joining keys with a hyphen.

// themes.css.ts

import { createGlobalThemeContract } from '@vanilla-extract/css';

export const vars = createGlobalThemeContract({
  color: {
    brand: null
  },
  font: {
    body: null
  }
}, (_value, path) => `prefix-${path.join('-')}`);

assignVars

Assigns a collection of CSS Variables anywhere within a style block.

💡 This is useful for creating responsive themes since it can be used within @media blocks.

import { createThemeContract, style, assignVars } from '@vanilla-extract/css';

export const vars = createThemeContract({
  space: {
    small: null,
    medium: null,
    large: null
  }
});

export const responsiveSpaceTheme = style({
  vars: assignVars(vars.space, {
    small: '4px',
    medium: '8px',
    large: '16px'
  }),
  '@media': {
    'screen and (min-width: 1024px)': {
      vars: assignVars(vars.space, {
        small: '8px',
        medium: '16px',
        large: '32px'
      })
    }
  }
});

💡 All variables passed into this function must be assigned or it’s a type error.

createVar

Creates a single CSS Variable.

import { createVar, style } from '@vanilla-extract/css';

export const colorVar = createVar();

export const exampleStyle = style({
  color: colorVar
});

Scoped variables can be set using the vars key.

import { createVar, style } from '@vanilla-extract/css';
import { colorVar } from './vars.css.ts';

export const parentStyle = style({
  vars: {
    [colorVar]: 'blue'
  }
});

fallbackVar

Provides fallback values when consuming variables.

import { createVar, fallbackVar, style } from '@vanilla-extract/css';

export const colorVar = createVar();

export const exampleStyle = style({
  color: fallbackVar(colorVar, 'blue'),
});

Multiple fallbacks are also supported.

import { createVar, fallbackVar, style } from '@vanilla-extract/css';

export const primaryColorVar = createVar();
export const secondaryColorVar = createVar();

export const exampleStyle = style({
  color: fallbackVar(primaryColorVar, secondaryColorVar, 'blue'),
});

fontFace

Creates a custom font attached to a locally scoped font name.

import { fontFace, style } from '@vanilla-extract/css';

const myFont = fontFace({
  src: 'local("Comic Sans MS")'
});

export const text = style({
  fontFamily: myFont
});

globalFontFace

Creates a globally scoped custom font.

import {
  globalFontFace,
  style
} from '@vanilla-extract/css';

globalFontFace('MyGlobalFont', {
  src: 'local("Comic Sans MS")'
});

export const text = style({
  fontFamily: 'MyGlobalFont'
});

keyframes

Creates a locally scoped set of keyframes.

import { keyframes, style } from '@vanilla-extract/css';

const rotate = keyframes({
  '0%': { transform: 'rotate(0deg)' },
  '100%': { transform: 'rotate(360deg)' }
});

export const animated = style({
  animation: `3s infinite ${rotate}`,
});

globalKeyframes

Creates a globally scoped set of keyframes.

import { globalKeyframes, style } from '@vanilla-extract/css';

globalKeyframes('rotate', {
  '0%': { transform: 'rotate(0deg)' },
  '100%': { transform: 'rotate(360deg)' }
});

export const animated = style({
  animation: `3s infinite rotate`,
});

Recipes API

Create multi-variant styles with a type-safe runtime API, heavily inspired by Stitches.

As with the rest of vanilla-extract, all styles are generated at build time.

$ npm install @vanilla-extract/recipes

recipe

Creates a multi-variant style function that can be used at runtime or statically in .css.ts files.

Accepts an optional set of base styles, variants, compoundVariants and defaultVariants.

import { recipe } from '@vanilla-extract/recipes';

export const button = recipe({
  base: {
    borderRadius: 6
  },

  variants: {
    color: {
      neutral: { background: 'whitesmoke' },
      brand: { background: 'blueviolet' },
      accent: { background: 'slateblue' }
    },
    size: {
      small: { padding: 12 },
      medium: { padding: 16 },
      large: { padding: 24 }
    },
    rounded: {
      true: { borderRadius: 999 }
    }
  },

  // Applied when multiple variants are set at once
  compoundVariants: [
    {
      variants: {
        color: 'neutral',
        size: 'large'
      },
      style: {
        background: 'ghostwhite'
      }
    }
  ],

  defaultVariants: {
    color: 'accent',
    size: 'medium'
  }
});

With this recipe configured, you can now use it in your templates.

import { button } from './button.css.ts';

document.write(`
  <button class="${button({
    color: 'accent',
    size: 'large',
    rounded: true
  })}">
    Hello world
  </button>
`);

Your recipe configuration can also make use of existing variables, classes and styles.

For example, you can pass in the result of your sprinkles function directly.

import { recipe } from '@vanilla-extract/recipes';
import { reset } from './reset.css.ts';
import { sprinkles } from './sprinkles.css.ts';

export const button = recipe({
  base: [reset, sprinkles({ borderRadius: 'round' })],

  variants: {
    color: {
      neutral: sprinkles({ background: 'neutral' }),
      brand: sprinkles({ background: 'brand' }),
      accent: sprinkles({ background: 'accent' })
    },
    size: {
      small: sprinkles({ padding: 'small' }),
      medium: sprinkles({ padding: 'medium' }),
      large: sprinkles({ padding: 'large' })
    }
  },

  defaultVariants: {
    color: 'accent',
    size: 'medium'
  }
});

Dynamic API

Dynamically update theme variables at runtime.

npm install @vanilla-extract/dynamic

assignInlineVars

Assigns CSS Variables as inline styles.

// app.tsx

import { assignInlineVars } from '@vanilla-extract/dynamic';
import { vars } from './vars.css.ts';

const MyComponent = () => (
  <section
    style={assignInlineVars({
      [vars.colors.brand]: 'pink',
      [vars.colors.accent]: 'green'
    })}
  >
    ...
  </section>
);

You can also assign collections of variables by passing a theme contract as the first argument. All variables must be assigned or it’s a type error.

// app.tsx

import { assignInlineVars } from '@vanilla-extract/dynamic';
import { vars } from './vars.css.ts';

const MyComponent = () => (
  <section
    style={assignInlineVars(vars.colors, {
      brand: 'pink',
      accent: 'green'
    })}
  >
    ...
  </section>
);

Even though this function returns an object of inline styles, its toString method returns a valid style attribute value so that it can be used in string templates.

// app.ts

import { assignInlineVars } from '@vanilla-extract/dynamic';
import { vars } from './vars.css.ts';

document.write(`
  <section style="${assignInlineVars({
    [vars.colors.brand]: 'pink',
    [vars.colors.accent]: 'green'
  })}">
    ...
  </section>
`);

setElementVars

Sets CSS Variables on a DOM element.

// app.ts

import { setElementVars } from '@vanilla-extract/dynamic';
import { vars } from './styles.css.ts';

const el = document.getElementById('myElement');

setElementVars(el, {
  [vars.colors.brand]: 'pink',
  [vars.colors.accent]: 'green'
});

You can also set collections of variables by passing a theme contract as the second argument. All variables must be set or it’s a type error.

// app.ts

import { setElementVars } from '@vanilla-extract/dynamic';
import { vars } from './styles.css.ts';

const el = document.getElementById('myElement');

setElementVars(el, vars.colors, {
  brand: 'pink',
  accent: 'green'
});

Utility functions

We also provide a standalone package of optional utility functions to make it easier to work with CSS in TypeScript.

💡 This package can be used with any CSS-in-JS library.

npm install @vanilla-extract/css-utils

calc

Streamlines the creation of CSS calc expressions.

import { calc } from '@vanilla-extract/css-utils';

const styles = {
  height: calc.multiply('var(--grid-unit)', 2)
};

The following functions are available.

• calc.add
• calc.subtract
• calc.multiply
• calc.divide
• calc.negate

The calc export is also a function, providing a chainable API for complex calc expressions.

import { calc } from '@vanilla-extract/css-utils';

const styles = {
  marginTop: calc('var(--space-large)')
    .divide(2)
    .negate()
    .toString()
};

---

Thanks

• Nathan Nam Tran for creating css-in-js-loader, which served as the initial starting point for treat, the precursor to this library.
• Stitches for getting us excited about CSS-Variables-in-JS.
• SEEK for giving us the space to do interesting work.

License

MIT.