Best of JS • Tokenami

Tokenami

Atomic CSS-in-JS, in the style attribute.

Type-safe static styles with theming, responsive variant support, and no bundler integration.

Why another CSS library?

CSS-in-JS solutions that rely on style injection won't be recommended by the React team going forward, and instead they suggest the following:

Our preferred solution is to use <link rel="stylesheet"> for statically extracted styles and plain inline styles for dynamic values. E.g. <div style={{...}}>

In other words—write CSS like we used to. But what about the benefits that CSS-in-JS gave us?

There are CSS-in-JS solutions that extract static rules from your template files into external .css files, however, these approaches often require bundler integration and come with build-time limitations.

The learning curve can be intimidating but developers invest regardless so they can have type errors and intellisense for their design system tokens as well as style deduping, critical path CSS, scoping, and composition.

Tailwind CSS adopts a different strategy to achieve these goals:

We can style inline to prototype quickly
Editor extensions for intellisense based on your theme
Statically generated styles with a simple CLI script, no bundler integration
Atomic CSS so styles have a cap on how large they can grow

On the flip side:

Removing values from your theme won't flag redundant references
We must memorise Tailwind's custom class names which spawns things like the Tailwind Cheatsheet
Specificity issues when composing unless we use third-party packages like tailwind-merge
Styling inline can be unpleasant to maintain, resulting in third-party packages like cva
Classes must exist as complete unbroken strings
Debugging in dev tools is tricky because styles are spread across atomic classes

Introducing Tokenami

Tokenami aims to improve some of these areas by using CSS variables instead of CSS properties in the style attribute, and bringing all necessary tools under one roof. It features:

Simple naming convention—use the CSS properties you already know, prefixed with double-dash
Smaller stylesheet made possible by atomic CSS variables
Config file for defining your theme
Feature-rich intellisense when authoring styles
A tiny css utility with variants, and responsive variants support
Seamless composition across component boundaries using the css utility
Runtime style support e.g. style={css({ '--color': props.color })}
Aliasable properties e.g. style={css({ '--p': 4 })} for padding
Custom selector support enabling sibling or descendant selectors
Improved debugging experience in dev tools
Statically generated styles
No bundler integration

Warning

This is a pre-alpha version of tokenami so there will be bugs, breaking changes, and missing features. Please check the existing issues for planned features/known bugs before creating new ones.

Demo

tokenami-demo.mp4

Getting started

Tokenami offers a CLI tool for generating static styles, a ~3kb CSS utility for authoring your styles, and a TypeScript plugin to enhance the developer experience.

Installation

Install using your package manager of choice. For example:

npm install @tokenami/dev @tokenami/ts-plugin -D
npm install @tokenami/css

And then initialise your tokenami project:

npx tokenami init

Configure TypeScript

Add Tokenami to include and plugins in your tsconfig.json or jsconfig.json.

{
  "include": [".tokenami/tokenami.env.d.ts", "**/*.ts", "**/*.tsx"],
  "compilerOptions": {
    "plugins": [{ "name": "@tokenami/ts-plugin" }]
  }
}

Make sure your editor is configured to use the project's version of TypeScript. You can find instructions for various editors in their documentation, such as for VSCode here.

Start the CLI watch script

Run the CLI tool to scan your template files for tokenami properties and build your CSS. This would usually exist as a script in your package.json.

npx tokenami --output ./public/styles.css --watch

Make sure to adjust the output path to your desired location for styles. It will use ./public/tokenami.css by default if omitted.

Use Tokenami

Reference your output CSS file in the <head> of your document, and start styling inline with Tokenami properties:

import { css } from '@tokenami/css';

function Page() {
  return <h1 style={css({ '--margin-top': 0, '--margin-bottom': 5 })}>Hello, World!</h1>;
}

Core concepts

Theming

Tokenami relies on your theme to provide design system constraints. There isn't a predefined theme so you must add your own to the .tokenami/tokenami.config. For example:

module.exports = createConfig({
  // ...
  responsive: {
    medium: '@media (min-width: 700px)',
    large: '@media (min-width: 1024px)',
  },
  theme: {
    color: {
      'slate-100': '#f1f5f9',
      'slate-700': '#334155',
      'sky-500': '#0ea5e9',
    },
    radii: {
      rounded: '10px',
      circle: '9999px',
      none: 'none',
    },
  },
});

The keys in your responsive and theme objects can be anything you wish. These keys will be used to name your tokens (more on this later).

Multiple themes

Use the modes key to set up multiple themes if preferred. The names of your modes can be anything you like:

module.exports = createConfig({
  theme: {
    modes: {
      light: {
        color: {
          primary: '#f1f5f9',
          secondary: '#334155',
        },
      },
      dark: {
        color: {
          primary: '#0ea5e9',
          secondary: '#f1f5f9',
        },
      },
    },
  },
});

By default this will apply the CSS variables to .theme-${mode} classes. Add the classes to an element on your page to apply the relevant theme.

Custom theme selector

To customise the theme selector, update the themeSelector config.

module.exports = createConfig({
  themeSelector: (mode) => (mode === 'root' ? ':root' : `.theme-${mode}`),
});

Styling

With your theme set up, there are only a few rules to remember:

A Tokenami property is any CSS property prefixed with double dash, e.g. --font-size. Use --- (triple dash) to add custom CSS variables to an element.
A Tokenami token is any theme key followed by a value identifier, separated by an underscore. For example, a color object in theme with a red-100 entry maps to var(--color_red-100).
Properties can include selectors like media queries, pseudo-classes, and pseudo-elements separated with an underscore. For instance, --hover_background-color, --md_hover_background-color.

Grid values

Tokenami uses a grid value for spacing. Properties like padding and margin are multiples of this when passed a numeric value. For example, with a grid set to 4px, using --padding: 2 adds 8px of padding to your element.

By default, Tokenami sets the grid to 0.25rem but you can override it:

module.exports = createConfig({
  // ...
  grid: '10px',
});

Arbitrary values

You can avoid TypeScript errors for one-off inline values by using a triple dash fallback. For instance, --padding: var(---, 20px) prevents errors and sets padding to 20px.

Tokenami intentionally adds friction to the developer experience here. This is to encourage sticking to your theme guidelines and to help you quickly spot values in your code that don't.

Responsive styles

Define responsive rules in the responsive object in your config. This can include @container queries:

module.exports = createConfig({
  // ...
  responsive: {
    medium: '@media (min-width: 1024px)',
    'medium-self': '@container (min-width: 400px)',
  },
});

Use by following the property spec:

<div style={css({ '--medium_padding': 4 })} />

Responsive rules can also be combined with selectors:

<div style={css({ '--medium_hover_padding': 4 })} />

For documentation on responsive variants, refer to the CSS compose section.

Animation

Add keyframes to your config and reference them in your theme:

module.exports = createConfig({
  // ...
  keyframes: {
    wiggle: {
      '0%, 100%': { transform: 'rotate(-3deg)' },
      '50%': { transform: 'rotate(3deg)' },
    },
  },
  theme: {
    anim: {
      wiggle: 'wiggle 1s ease-in-out infinite',
    },
  },
});

Use by following the token spec:

<div style={css({ '--animation': 'var(--anim_wiggle)' })} />

CSS utility

Tokenami provides a CSS utility to author your styles and correctly merge them across component boundaries.

Usage

The css utility accepts your base styles as the first parameter, and then any number of overrides as additional parameters.

function Button({ size, style, ...props }) {
  return <button {...props} style={css({ '--padding': 4 }, props.style)} />;
}

In the above example, we're passing props.style as an override to ensure composed styles will merge correctly across component boundaries.

Overrides

Overrides can be applied conditionally and last override wins. They are applied as additional parameters to the css utility.

function Button({ style, ...props }) {
  const disabled = props.disabled && { '--opacity': 0.5 };
  return <button {...props} style={css({ '--p': 4 }, disabled, style)} />;
}

CSS compose

Use the css.compose API to author variants.

Variants

const button = css.compose({
  '--padding': 4,

  variants: {
    size: {
      small: { '--padding': 2 },
      large: { '--padding': 6 },
    },
  },
});

function Button({ size, style, ...props }) {
  return <button {...props} style={button({ size }, style)} />;
}

The function returned by css.compose accepts your chosen variants as the first parameter, and then any number of overrides as additional parameters.

Responsive variants

Responsive variants allow you to prefix the variant name with a responsive key from your configuration. For example, the following button will apply the large size variant at the medium breakpoint:

function Button() {
  return <button style={button({ medium_size: 'large' })} />;
}

To enable it, rename the variants property to responsiveVariants. This will generate the atomic CSS for the responsive variants regardless of whether they're used, so it is purposefully opt-in to allow greater control.

const button = css.compose({
  '--padding': 4,

-  variants: {
+  responsiveVariants: {
    size: {
      small: { '--padding': 2 },
      large: { '--padding': 6 },
    },
  },
});

TypeScript

Variants

Use the Variants type to extend your component prop types:

import { type Variants } from '@tokenami/css';

type ButtonElementProps = React.ComponentPropsWithoutRef<'button'>;
interface ButtonProps extends ButtonElementProps, Variants<typeof button> {}

TokenamiStyle

Use TokenamiStyle to accept the css utility as a value for the style prop. This prevents errors when props.style is used for overrides.

import { type TokenamiStyle, css } from '@tokenami/css';

interface ButtonProps extends TokenamiStyle<React.ComponentProps<'button'>> {}

function Button(props: ButtonProps) {
  return <button {...props} style={css({}, props.style)} />;
}

Advanced

Selectors

Tokenami provides some common default selectors for you but you can define your own custom selectors in the selectors object of your config.

Use the ampersand (&) to specify where the current element's selector should be injected:

const { createConfig, defaultConfig } = require('@tokenami/css');

module.exports = createConfig({
  // ...
  selectors: {
    ...defaultConfig.selectors,
    'parent-hover': '.parent:hover > &',
  },
});

Use by following the property spec:

<div className="parent">
  <img src="..." alt="" />
  <button style={css({ '--parent-hover_font-weight': 'bold' })} />
</div>

Selectors can also be combined with responsive rules:

<button style={css({ '--medium_parent-hover_font-weight': 'bold' })} />

Nested selectors

Use an array value for custom selectors to generate nested rules:

module.exports = createConfig({
  // ...
  selectors: {
    ...defaultConfig.selectors,
    hover: ['@media (hover: hover) and (pointer: fine)', '&:hover'],
  },
});

This example will apply hover styles for users with a precise pointing device, such as a mouse, when --hover_{property} is used.

Aliases

Aliases allow you to create shorthand names for properties. When using custom aliases, the css utility must be configured to ensure aliased properties are merged correctly across component boundaries.

Configure utility

Create a file in your project to configure the utility. You can name this file however you like, e.g. css.ts:

// css.ts
import { createCss } from '@tokenami/css';
import config from '../.tokenami/tokenami.config';

export const css = createCss(config);

Use the css utility exported from the file you created and it will handle aliases correctly.

Create aliases

The configuration expects the name of your new alias followed by an array of properties it maps to.

module.exports = createConfig({
  // ...
  aliases: {
    p: ['padding'],
    px: ['padding-left', 'padding-right'],
    py: ['padding-top', 'padding-bottom'],
    pt: ['padding-top'],
    pr: ['padding-right'],
    pb: ['padding-bottom'],
    pl: ['padding-left'],
    size: ['width', 'height'],
  },
});

With the above config, px is shorthand for padding-left and padding-right. This allows the css utility to apply padding on the left and right when --px is used.

Mapping properties to theme

Tokenami provides sensible defaults to restrict which values can be passed to properties based on your theme. For instance, --border-color will only accept tokens from your color object in theme, --padding allows multiples of your grid, and --height expects tokens from a size key or multiples of your grid.

You can customise the default configuration by overriding the properties object:

const { createConfig, defaultConfig } = require('@tokenami/css');

module.exports = createConfig({
  theme: {
    container: {
      half: '50%',
    },
    pet: {
      cat: '"🐱"',
      dog: '"🐶"',
    },
  },
  properties: {
    ...defaultConfig.properties,
    width: ['grid', 'container'],
    height: ['grid', 'container'],
    content: ['pet'],
  },
});

With this configuration, using '--content': 'var(--container_half)' would error because container does not exist in the property config for content, but '--content': 'var(--pet_dog)' would be allowed:

<div
  style={css({
    '--width': 75 /*  300px with a 4px grid */,
    '--height': 'var(--container_half)',
    '--after_content': 'var(--pet_cat)',
  })}
/>

Browserslist

Tokenami only supports browserslist in your package.json. You can use it to add autoprefixing to your CSS properties in the generated CSS file. However, it currently doesn't support vendor-prefixed values, which is being tracked in this issue.

Note

Tokenami does not support browsers below the listed supported browser versions.

Continuous Integration

To improve performance during development, Tokenami widens its types and uses the TypeScript plugin for completions. Using tsc in the command line defaults to these widened types so it will not highlight errors for your properties or tokens. To get accurate types for CI, do the following:

Create a CI project config

Create a file named tsconfig.ci.json or jsconfig.ci.json. It should extend your original config and include the CI-specific Tokenami types:

{
  "extends": "./tsconfig.json",
  "include": [".tokenami/tokenami.env.ci.d.ts", "**/*.ts", "**/*.tsx"]
}

Reference CI project config

For CI, use tsc with your new configuration:

tsc --noEmit --project tsconfig.ci.json

Design systems with Tokenami

Integrating a design system built with Tokenami is straightforward. Include the tokenami.config.js file and corresponding stylesheet from the design system in your project:

import designSystemConfig from '@acme/design-system';
import { createConfig } from '@tokenami/css';

export default createConfig({
  ...designSystemConfig,
  include: ['./app/**/*.{ts,tsx}', 'node_modules/@acme/design-system/tokenami.css'],
});

Tokenami will automatically generate styles and merge them correctly across component boundaries. See the example design system project and Remix project for a demo.

Support

Before raising a bug, please double-check that it isn't already in my todo list. Some common pitfalls are listed below. If you need additional support or encounter any issues, please don't hesitate to join the Tokenami discord server.

Supported frameworks

Tokenami is in early stages of development and currently only supports applications built using React or SolidJS.

Supported browsers

Tokenami relies on cascade layers so only supports browsers with @layer support.

Edge	Firefox	Chrome	Safari	iOS Safari	Opera
99+	97+	99+	15.4+	15.4+	86+

HMR not working as expected in Remix

When adding the stylesheet to the links export, make sure to import it instead of referencing a path in the href property:

import styles from '~/tokenami.css';

export const links: LinksFunction = () => [{ rel: 'stylesheet', href: styles }];

If your stylesheet is outside the remix app directory, update remix.config.js to include it in watchPaths and update the import path appropriately.

Contributors

Paweł Błaszczyk (@pawelblaszczyk_)

Credits

A big thanks to:

Tailwind CSS for inspiring most of the features in Tokenami
Stitches for variants and responsive variants inspiration
CSS Hooks for custom selectors inspiration
Lightning CSS for generating the Tokenami stylesheet

Please do take the time to check these projects out if you feel Tokenami isn't quite right for you.

module.exports = createConfig({ // ... responsive: { medium: '@media (min-width: 700px)', large: '@media (min-width: 1024px)', }, theme: { color: { 'slate-100': '#f1f5f9', 'slate-700': '#334155', 'sky-500': '#0ea5e9', }, radii: { rounded: '10px', circle: '9999px', none: 'none', }, }, });

module.exports = createConfig({ theme: { modes: { light: { color: { primary: '#f1f5f9', secondary: '#334155', }, }, dark: { color: { primary: '#0ea5e9', secondary: '#f1f5f9', }, }, }, }, });

module.exports = createConfig({ // ... keyframes: { wiggle: { '0%, 100%': { transform: 'rotate(-3deg)' }, '50%': { transform: 'rotate(3deg)' }, }, }, theme: { anim: { wiggle: 'wiggle 1s ease-in-out infinite', }, }, });

const button = css.compose({ '--padding': 4, variants: { size: { small: { '--padding': 2 }, large: { '--padding': 6 }, }, }, }); function Button({ size, style, ...props }) { return <button {...props} style={button({ size }, style)} />; }

import { type TokenamiStyle, css } from '@tokenami/css'; interface ButtonProps extends TokenamiStyle<React.ComponentProps<'button'>> {} function Button(props: ButtonProps) { return <button {...props} style={css({}, props.style)} />; }

const { createConfig, defaultConfig } = require('@tokenami/css'); module.exports = createConfig({ // ... selectors: { ...defaultConfig.selectors, 'parent-hover': '.parent:hover > &', }, });

module.exports = createConfig({ // ... aliases: { p: ['padding'], px: ['padding-left', 'padding-right'], py: ['padding-top', 'padding-bottom'], pt: ['padding-top'], pr: ['padding-right'], pb: ['padding-bottom'], pl: ['padding-left'], size: ['width', 'height'], }, });

const { createConfig, defaultConfig } = require('@tokenami/css'); module.exports = createConfig({ theme: { container: { half: '50%', }, pet: { cat: '"🐱"', dog: '"🐶"', }, }, properties: { ...defaultConfig.properties, width: ['grid', 'container'], height: ['grid', 'container'], content: ['pet'], }, });

import designSystemConfig from '@acme/design-system'; import { createConfig } from '@tokenami/css'; export default createConfig({ ...designSystemConfig, include: ['./app/**/*.{ts,tsx}', 'node_modules/@acme/design-system/tokenami.css'], });

Edge

Firefox

Chrome

Safari

iOS Safari

Opera

99+

97+

99+

15.4+

86+

Tokenami

Tokenami

Why another CSS library?

Introducing Tokenami

Demo

Contents

Getting started

Installation

Configure TypeScript

Start the CLI watch script

Use Tokenami

Core concepts

Theming

Multiple themes

Custom theme selector

Styling

Grid values

Arbitrary values

Responsive styles

Animation

CSS utility

Usage

Overrides

CSS compose

Variants

Responsive variants

TypeScript

Variants

TokenamiStyle

Advanced

Selectors

Nested selectors

Aliases

Configure utility

Create aliases

Mapping properties to theme

Browserslist

Continuous Integration

Create a CI project config

Reference CI project config

Design systems with Tokenami

Support

Supported frameworks

Supported browsers

HMR not working as expected in Remix

Contributors

Credits

Tokenami

Why another CSS library?

Introducing Tokenami

Demo

Contents

Getting started

Installation

Configure TypeScript

Start the CLI watch script

Use Tokenami

Core concepts

Theming

Multiple themes

Custom theme selector

Styling

Grid values

Arbitrary values

Responsive styles

Animation

CSS utility

Usage

Overrides

CSS compose

Variants

Responsive variants

TypeScript

Variants

TokenamiStyle

Advanced

Selectors

Nested selectors

Aliases

Configure utility