Guides

Using Panda in a Component Library

When creating a component library that uses Panda which can be used in a variety of different projects, you have four options:

1. Ship a Panda preset
2. Ship a static CSS file
3. Use Panda as external package, and ship the src files
4. Use Panda as external package, and ship the build info file

Recommendations

• If your library code shouldn't be published on npm and App code uses Panda, use ship build info approach
• If your app code doesn't use Panda, use the static css file approach
• If your app code lives in a monorepo, use the include src files approach
• If your library code doesn't ship components but only ships tokens, patterns or recipes, use the ship preset approach

Ship a Panda Preset

This is the simplest approach. You can include the token, semantic tokens, text styles, etc. within a preset and consume them in your projects.

Library code

import { definePreset } from '@pandacss/dev'
 
export const acmePreset = definePreset({
  theme: {
    extend: {
      tokens: {
        colors: { primary: { value: 'blue.500' } }
      }
    }
  }
})

Build the preset code

pnpm tsup src/index.ts

App code

import { acmePreset } from '@acme-org/panda-preset'
import { defineConfig } from '@pandacss/dev'
 
export default defineConfig({
  //...
  presets: ['@pandacss/dev/presets', acmePreset]
})

Ship a Static CSS File

This approach involves extracting the static css of your library at build time. Then you can import the CSS file in your app code.

Library code

import { css } from '../styled-system/css'
 
export function Button({ children }) {
  return (
    <button type="button" className={css({ bg: 'red.300', px: '2', py: '3' })}>
      {children}
    </button>
  )
}

Then you can build the library code and generate the static CSS file:

# build the library code
tsup src/index.tsx
 
# generate the static CSS file
panda cssgen --outfile dist/styles.css

Finally, don't forget to include the cascade layers as well in your app code:

App code

import { Button } from '@acme-org/design-system'
import './main.css'
 
export function App() {
  return <Button>Click me</Button>
}

main.css

@layer reset, base, tokens, recipes, utilities;
@import url('@acme-org/design-system/dist/styles.css');
 
/* Your own styles here */

This approach comes with a few downsides:

• You can't customize the styles since the css is already generated

• You might need add the prefix option to avoid className conflicts

  import { defineConfig } from '@pandacss/dev'
   
  export default defineConfig({
    //...
    prefix: 'acme'
  })

• You might have duplicate CSS classes when using multiple atomic css libraries

Use Panda as external package

Summary

• create a Panda preset so that you (and your users) can share the same design system tokens
• create a workspace package for your outdir (@acme-org/styled-system) and use that package name as the importMap in your app code
• have your component library (@acme-org/components) use the @acme-org/styled-system package as external

Let's make a dedicated workspace package for your outdir:

1. Create a new directory packages/styled-system (or any other name)
2. Install @pandacss/dev as a dev dependency
3. Run the panda init command in there to generate a panda.config.ts file, don't forget to set the jsxFramework if needed
4. [optional] you might want to install and import your preset in this panda.config.ts file as well
5. Run the panda emit-pkg command to set the entrypoints in exports (opens in a new tab)

This should look similar to this:

{
  "name": "@acme-org/styled-system",
  "version": "1.0.0",
  "devDependencies": {
    "@pandacss/dev": "^0.27.3"
  },
  "exports": {
    "./css": {
      "types": "./css/index.d.ts",
      "require": "./css/index.mjs",
      "import": "./css/index.mjs"
    },
    "./tokens": {
      "types": "./tokens/index.d.ts",
      "require": "./tokens/index.mjs",
      "import": "./tokens/index.mjs"
    },
    "./types": {
      "types": "./types/index.d.ts",
      "require": "./types/index.mjs",
      "import": "./types/index.mjs"
    },
    "./patterns": {
      "types": "./patterns/index.d.ts",
      "require": "./patterns/index.mjs",
      "import": "./patterns/index.mjs"
    },
    "./recipes": {
      "types": "./recipes/index.d.ts",
      "require": "./recipes/index.mjs",
      "import": "./recipes/index.mjs"
    },
    "./jsx": {
      "types": "./jsx/index.d.ts",
      "require": "./jsx/index.mjs",
      "import": "./jsx/index.mjs"
    },
    "./styles.css": "./styles.css"
  }
}

Going forward, you'll now import the functions from the @acme-org/styled-system monorepo package.

import { css } from '@acme-org/styled-system/css'
 
export function Button({ children }) {
  return (
    <button type="button" className={css({ bg: 'red.300', px: '2', py: '3' })}>
      {children}
    </button>
  )
}

App code

Install the newly created @acme-org/styled-system package in your app code.

pnpm add @acme-org/styled-system

Configure the importMap in your panda.config.ts to match the name field of your outdir package.json. This will inform Panda which imports belong to the styled-system.

import { defineConfig } from '@pandacss/dev'
 
export default defineConfig({
  //...
  importMap: '@acme-org/styled-system',
  outdir: 'styled-system'
})

Mark the @acme-org/styled-system as an external package in your library build tool. This ensures that the generated JS runtime code is imported only once, avoiding duplication.

tsup src/index.tsx --external @acme-org/styled-system

Include the src files

Include the src directory from the library code in the panda config.

import { defineConfig } from '@pandacss/dev'
 
export default defineConfig({
  //...
  include: ['../@acme-org/design-system/src/**/*.tsx', './src/**/*.{ts,tsx}'],
  importMap: '@acme-org/styled-system',
  outdir: 'styled-system'
})

Ship the build info file

This approach is similar to the previous one, but instead of shipping the source code, you ship the Panda build info file. This will have the exact same end-result as adding the sources files in the include, but it will allow you not to ship the source code.

The build info file is a JSON file that only contains the information about the static extraction result, you still need to ship your app build/dist by yourself. It can be used by Panda to generate CSS classes without the need for parsing the source code.

Generate the build info file:

panda ship --outfile dist/panda.buildinfo.json

App code

Install the newly created @acme-org/styled-system package in your app code.

pnpm add @acme-org/styled-system

Configure the importMap in your panda.config.ts to match the name field of your outdir package.json. This will inform Panda which imports belong to the styled-system.

import { defineConfig } from '@pandacss/dev'
 
export default defineConfig({
  //...
  importMap: '@acme-org/styled-system',
  outdir: 'styled-system'
})

Will allow imports like:

import { css } from '@acme-org/styled-system/css'
import { button } from '@acme-org/styled-system/recipes'

Next, you need to include the build info file from the library code in the panda config.

import { defineConfig } from '@pandacss/dev'
 
export default defineConfig({
  //...
  include: [
    './node_modules/@acme-org/design-system/dist/panda.buildinfo.json',
    './src/**/*.{ts,tsx}'
  ],
  importMap: '@acme-org/styled-system',
  outdir: 'styled-system'
})

FAQ

Why should my component library use an external package styled-system?

By de-coupling the component library from the styled-system, your users can share the same runtime code between your library and their app code.

import { css } from '@acme-org/styled-system/css'
 
export function Button({ children, css: cssProp }) {
  return (
    <button
      type="button"
      className={css({ bg: 'red.300', px: '2', py: '3' }, cssProp)}
    >
      {children}
    </button>
  )
}

import { Button } from '@acme-org/design-system'
import { css } from '@acme-org/styled-system/css'
 
export function App() {
  return <Button css={{ color: 'white' }}>Click me</Button>
}

Marking the styled-system as an external package in your build tool means that the generated JS runtime code (the css function is the example above) is imported only once, avoiding duplication.

How do I use the @acme-org/styled-system package ?

You can use your monorepo workspace package @acme-org/styled-system just like any other dependency in your app or component library code.

pnpm add @acme-org/styled-system

Set the importMap in your panda.config.ts to that same package name. This will inform Panda which imports belong to the styled-system.

import { defineConfig } from '@pandacss/dev'
 
export default defineConfig({
  //...
  importMap: '@acme-org/styled-system'
})

Then you can import the functions from the @acme-org/styled-system monorepo package.

import { css } from '@acme-org/styled-system/css'
 
export function Button({ children }) {
  return (
    <button type="button" className={css({ bg: 'red.300', px: '2', py: '3' })}>
      {children}
    </button>
  )
}

How to override tokens used by the @acme-org/styled-system package?

You can override the tokens used by the @acme-org/styled-system package by extending the theme in your panda.config.ts file.

import { defineConfig } from '@pandacss/dev'
 
export default defineConfig({
  //...
  presets: ['@acme-org/preset']
  theme: {
    extend: {
      tokens: {
        colors: { primary: { value: 'blue.500' } }
      }
    }
  }
})

Troubleshooting

• When using tsup or any other build tool for your component library, if you run into a module resolution error that looks similar to ERROR: Could not resolve "../styled-system/xxx". Consider setting the outExtensionin the panda config tojs

• If you use Yarn PnP, you might need to set the nodeLinker: node-modules in the .yarnrc.yml file.