@mertasan/tailwindcss-variables

Tailwind CSS Variables

This package provides an easy way to define CSS variables for your Tailwind CSS project. You can use this package to create custom variables within your Tailwind configuration. This makes it easier to maintain consistency across your CSS, reduces repetition, allows you to configure variables based on various conditions, and eliminates the need to work directly with your CSS files to determine variables.

Similar to the tailwindcss configurations you are used to. It is also possible to define a different group of variables for Dark Mode. Alternatively, it has an API that you can use for your own plugins.

Highlights

• Variables are as easy as defining tailwindcss colors...
• You can designate the variables to :root, :host or custom CSS selectors.
• Variables can be formed through using nested object notation.
• Different variables can be composed for the Dark Mode.
• Dark Mode variables are set automatically through the class or media modes on your configuration.
• Dark Mode custom selector is inherited from Tailwind configuration
• It allows you to add custom themes while creating your own plugin via the plugin API.
• Prefix can be defined for variables. (It is useful when using the plugin API)
• You can configure your own needs such as multi-themes without needing an additional plugin!

Documentation

Language	Documentation link
English	Documentation
Turkish	Dökümantasyon

Version Compatibility

Tailwind CSS	Package
2.x	1.x
3.x	2.x

Installation

npm install -D @mertasan/tailwindcss-variables

Playground

Simple example: https://play.tailwindcss.com/hCpcvnGsPx?file=config

Usage

// tailwind.config.js

module.exports = {
  theme: {
    colors: {
        red: {
            50: 'var(--colors-red-50)'
        }
    },
    variables: {
      DEFAULT: {
        sizes: {
          small: '1rem',
          button: {
            size: '2rem'
          }
        },
        colors: {
          red: {
            50: '#ff3232',
          },
        },
      },
      '.container': {
        sizes: {
          medium: '1.5rem',
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')
  ]
}

Output:

:root {
  --sizes-small: 1rem;
  --sizes-button-size: 2rem;
  --colors-red-50: #ff3232
}

.container {
  --sizes-medium: 1.5rem
}

Dark Mode

with the class mode

// tailwind.config.js

module.exports = {

  darkMode: 'class',

  theme: {
    variables: {
      DEFAULT: {
        sizes: {
          small: '1rem',
        },
        colors: {
          red: {
            50: 'red',
          },
        },
      },
      '.container': {
        colors: {
          red: {
            50: 'indigo',
          },
        },
      },
    },
    darkVariables: {
      DEFAULT: {
        colors: {
          red: {
            50: 'blue',
          },
        },
      },
      '.container': {
        colors: {
          red: {
            50: 'green',
          },
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')
  ]
}

Output:

:root {
  --sizes-small: 1rem;
  --colors-red-50: red
}

.container {
  --colors-red-50: indigo
}

:root.dark {
  --colors-red-50: blue
}

:root.dark .container {
  --colors-red-50: green
}

Custom dark selector

Note that the plugin will use your custom selector if enabled in your Tailwind configuration.

// tailwind.config.js

module.exports = {

  darkMode: ['class', '.custom-dark-selector'],

  theme: {
    variables: {
      DEFAULT: {
        colors: {
          red: {
            50: 'red',
          },
        },
      },
    },
    darkVariables: {
      DEFAULT: {
        colors: {
          red: {
            50: 'blue',
          },
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')
  ]
}

Output:

:root {
  --colors-red-50: red
}

:root.custom-dark-selector {
  --colors-red-50: blue
}

with the darkToRoot configuration

If the darkMode configuration is set as 'class' in your tailwindcss configuration, you can change and customize the darkToRoot setting.

// tailwind.config.js

module.exports = {

  darkMode: ['class', '.custom-dark-selector'],

  theme: {
    variables: {
      DEFAULT: {
        sizes: {
          small: '1rem',
        },
        colors: {
          red: {
            50: 'red',
          },
        },
      },
      '.container': {
        colors: {
          red: {
            50: 'indigo',
          },
        },
      },
    },
    darkVariables: {
      DEFAULT: {
        colors: {
          red: {
            50: 'blue',
          },
        },
      },
      '.container': {
        colors: {
          red: {
            50: 'green',
          },
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')({
      darkToRoot: false,
    })
  ]
}

Output:

:root {
    --sizes-small: 1rem;
    --colors-red-50: red
}

.container {
    --colors-red-50: indigo
}

.custom-dark-selector {
    --colors-red-50: blue
}

.custom-dark-selector .container {
    --colors-red-50: green
}

with the media mode

// tailwind.config.js

module.exports = {

  darkMode: 'media',

  theme: {
    variables: {
      DEFAULT: {
        sizes: {
          small: '1rem',
        },
        colors: {
          red: {
            50: 'red',
          },
        },
      },
      '.container': {
        colors: {
          red: {
            50: 'indigo',
          },
        },
      },
    },
    darkVariables: {
      DEFAULT: {
        colors: {
          red: {
            50: 'blue',
          },
        },
      },
      '.container': {
        colors: {
          red: {
            50: 'green',
          },
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')
  ]
}

Output:

:root {
  --sizes-small: 1rem;
  --colors-red-50: red
}

.container {
    --colors-red-50: indigo
}

@media (prefers-color-scheme: dark) {
  :root {
    --colors-red-50: blue
  }

  .container {
    --colors-red-50: green
  }
}

Prefix

// tailwind.config.js

module.exports = {
  theme: {
    variables: {
      DEFAULT: {
        sizes: {
          small: '1rem',
          button: {
            size: '2rem'
          }
        },
        colors: {
          red: {
            50: '#ff3232',
          },
        },
      },
      '.container': {
        sizes: {
          medium: '1.5rem',
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')({
      variablePrefix: 'admin'
    })
  ]
}

Output:

:root {
  --admin-sizes-small: 1rem;
  --admin-sizes-button-size: 2rem;
  --admin-colors-red-50: #ff3232
}

.container {
    --admin-sizes-medium: 1.5rem
}

Nested object notation

// tailwind.config.js

module.exports = {
  theme: {
    variables: {
      DEFAULT: {
        sizes: {
          DEFAULT: '1px',
          small: '1rem',
          admin: {
            DEFAULT: '2px',
            buttons: {
              colors: {
                red: {
                  DEFAULT: '#ffffff',
                  500: '#ff0000',
                  600: '#e60000',
                }
              }
            }
          }
        },
      }
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')
  ]
}

:root {
  --sizes: 1px;
  --sizes-small: 1rem;
  --sizes-admin: 2px;
  --sizes-admin-buttons-colors-red-500: #ff0000;
  --sizes-admin-buttons-colors-red-600: #e60000;
  --sizes-admin-buttons-colors-red: #ffffff
}

Rules for keys of variables

Variable keys can only include designated characters. Other characters will be automatically removed. Because using underscores (_) on objects is allowed, underscores will be transformed into middle dashes (-).

Rule:

/[^a-zA-Z0-9-.]+/gi

Before	After
hello[$&+,:;=?@#'<>-^*()%!]WORLD	hello-WORLD
hello__world	hello-world
css_variables_for-tailwindcss	css-variables-for-tailwindcss
foo-bar-1.0	foo-bar-1\.0

Here's an example:

// tailwind.config.js

module.exports = {
  theme: {
    variables: {
      DEFAULT: {
        colors: {
          'hello[$&+,:;=?@#|\'<>-^*()%!]WORLD': '100%',
          underscore_to_dash: '100%',
          'underscore_to_dash-with-dash': '100%',
          auto_dash: '100%',
        },
        sizes: {
          1.5: '1rem',
          xl: {
            '3.0': '2rem',
          },
        },
      },
      '[type=\'button\']': {
        'hello[$&+,:;=?@#|\'<>-^*()%!]WORLD': '100%',
        underscore_to_dash: '100%',
        'underscore_to_dash-with-dash': '100%',
        auto_dash: '100%',
        nested_auto_dash: {
          color_primary: '100%',
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')
  ]
}

Output:

:root {
  --colors-hello-WORLD: 100%;
  --colors-underscore-to-dash: 100%;
  --colors-underscore-to-dash-with-dash: 100%;
  --colors-auto-dash: 100%;
  --sizes-1\.5: 1rem;
  --sizes-xl-3\.0: 2rem
}

[type='button'] {
  --hello-WORLD: 100%;
  --underscore-to-dash: 100%;
  --underscore-to-dash-with-dash: 100%;
  --auto-dash: 100%;
  --nested-auto-dash-color-primary: 100%
}

Helpers

colorVariable()

You can use the colorVariable helper to add text-opacity or bg-opacity to the variables for which colors are defined.

// tailwind.config.js

const colorVariable = require('@mertasan/tailwindcss-variables/colorVariable')

module.exports = {
  theme: {
    screens: false,
    colors: {
      primary: colorVariable('--colors-primary'), // HEX (3 digits)
      secondary: colorVariable('var(--colors-secondary)'), // HEX (6 digits)
      white: '#ffffff', // no variable
      blue: colorVariable('var(--colors-blue)'), // RGB
      red: {
        400: colorVariable('var(--colors-red-400)'), // RGBA
        500: colorVariable('var(--colors-red-500)'), // RGBA
        600: 'var(--colors-red-500)', // RGBA (without using colorVariable() helper)
      },
      gray: 'var(--colors-gray)', // HEX (6 digits) (without using colorVariable() helper)
      green: 'var(--colors-green)', // RGB (without using colorVariable() helper)
    },
    variables: {
      DEFAULT: {
        colors: {
          primary: '#ff0',
          secondary: '#000000',
          gray: '#6B7280',
          blue: 'rgb(0,0,254)',
          red: {
            400: 'rgba(254,0,0,0.5)',
            500: 'rgba(254,0,0,1)',
          },
          green: 'rgb(0,255,0)',
        },
        sizes: {
          small: '10px',
          medium: '2rem',
          large: '100%',
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')({
      colorVariables: true
    })
  ]
}

Purge:

<div class="text-opacity-50 text-primary"></div>
<div class="bg-opacity-50 bg-secondary"></div>
<div class="bg-opacity-50 bg-gray"></div>
<div class="text-opacity-50 text-blue"></div>
<div class="bg-red-400"></div>
<div class="bg-red-500"></div>
<div class="bg-red-600"></div>
<div class="bg-opacity-50 bg-green"></div>
<div class="bg-white bg-opacity-50"></div>

Output:

:root {
  --colors-primary: #ff0;
  --colors-secondary: #000000;
  --colors-gray: #6B7280;
  --colors-blue: rgb(0,0,254);
  --colors-red-400: rgba(254,0,0,0.5);
  --colors-red-500: rgba(254,0,0,1);
  --colors-red-400-rgb: 254,0,0;
  --colors-red-500-rgb: 254,0,0;
  --colors-green: rgb(0,255,0);
  --colors-primary-rgb: 255,255,0;
  --colors-secondary-rgb: 0,0,0;
  --colors-gray-rgb: 107,114,128;
  --colors-blue-rgb: 0,0,254;
  --colors-green-rgb: 0,255,0;
  --sizes-small: 10px;
  --sizes-medium: 2rem;
  --sizes-large: 100%
}

.text-primary {
 --tw-text-opacity: 1;
 color: rgba(var(--colors-primary-rgb), var(--tw-text-opacity))
}

.text-blue {
 --tw-text-opacity: 1;
 color: rgba(var(--colors-blue-rgb), var(--tw-text-opacity))
}

.text-opacity-50 {
 --tw-text-opacity: 0.5
}

.bg-secondary {
 --tw-bg-opacity: 1;
 background-color: rgba(var(--colors-secondary-rgb), var(--tw-bg-opacity))
}

.bg-white {
 --tw-bg-opacity: 1;
 background-color: rgba(255, 255, 255, var(--tw-bg-opacity))
}

.bg-red-400 {
 --tw-bg-opacity: 1;
 background-color: rgba(var(--colors-red-400-rgb), var(--tw-bg-opacity))
}

.bg-red-500 {
 --tw-bg-opacity: 1;
 background-color: rgba(var(--colors-red-500-rgb), var(--tw-bg-opacity))
}

.bg-red-600 {
  background-color: var(--colors-red-500)
}

.bg-gray {
 background-color: var(--colors-gray)
}

.bg-green {
 background-color: var(--colors-green)
}

.bg-opacity-50 {
 --tw-bg-opacity: 0.5
}

forceRGB

If forceRGB is set to true, no additional variables are created.

Before

// tailwind.config.js

const colorVariable = require('@mertasan/tailwindcss-variables/colorVariable')

module.exports = {
  theme: {
    screens: false,
    colors: {
      green: colorVariable('var(--colors-green)'),
    },
    variables: {
      DEFAULT: {
        colors: {
          green: '#11ff00',
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')({
      colorVariables: true,
    })
  ]
}

Output:

:root {
  --colors-green: #11ff00;
  --colors-green-rgb: 17,255,0
}

.text-green {
  --tw-text-opacity: 1;
  color: rgba(var(--colors-green-rgb), var(--tw-text-opacity))
}

After

// tailwind.config.js

const colorVariable = require('@mertasan/tailwindcss-variables/colorVariable')

module.exports = {
  theme: {
    screens: false,
    colors: {
      green: colorVariable('var(--colors-green)', true),
    },
    variables: {
      DEFAULT: {
        colors: {
          green: '#11ff00',
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')({
      colorVariables: true,
      forceRGB: true,
    })
  ]
}

Output:

:root {
  --colors-green: 17,255,0;
}

.text-green {
  --tw-text-opacity: 1;
  color: rgba(var(--colors-green), var(--tw-text-opacity))
}

useHost

If useHost is set to true, :host is used instead of :root for variables injection.

Config

// tailwind.config.js

module.exports = {
  theme: {
    variables: {
      DEFAULT: {
        colors: {
          green: '#11ff00',
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')({
      useHost: true,
    })
  ]
}

Output:

:host {
  --colors-green: #11ff00;
}

extendColors for colorVariable

Instead of using each of the colors between the variables as colorVariable('var(--colors-red)'), You can define colors in the extendColors option.

Example:

// tailwind.config.js

module.exports = {
  theme: {
    screens: false,
    colors: {
      white: '#fff',
      green: 'var(--colors-green)',
    },
    variables: {
      DEFAULT: {
        colors: {
          blue: '#0065ff',
          red: '#ff0000',
          green: '#11ff00',
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')({
      colorVariables: true,
      extendColors: {
        blue: 'var(--colors-blue)',
        red: 'var(--colors-red)',
      }
    })
  ]
}

Output:

:root {
  --colors-blue: #0065ff;
  --colors-red: #ff0000;
  --colors-green: #11ff00;
  --colors-blue-rgb: 0,101,255;
  --colors-red-rgb: 255,0,0;
  --colors-green-rgb: 17,255,0
}

.text-white {
  --tw-text-opacity: 1;
  color: rgba(255, 255, 255, var(--tw-text-opacity))
}

.text-green {
  color: var(--colors-green)
}

.text-blue {
  --tw-text-opacity: 1;
  color: rgba(var(--colors-blue-rgb), var(--tw-text-opacity))
}

.text-red {
  --tw-text-opacity: 1;
  color: rgba(var(--colors-red-rgb), var(--tw-text-opacity))
}

.text-opacity-50 {
  --tw-text-opacity: 0.5
}

Example 2 - Using with forceRGB:

// tailwind.config.js

module.exports = {
  theme: {
    screens: false,
    colors: {
      white: '#fff',
      green: 'var(--colors-green)',
    },
    variables: {
      DEFAULT: {
        colors: {
          blue: '#0065ff',
          red: '#ff0000',
          green: '#11ff00',
        },
      },
    },
  },
  plugins: [
    require('@mertasan/tailwindcss-variables')({
      colorVariables: true,
      forceRGB: true,
      extendColors: {
        blue: 'var(--colors-blue)',
        red: 'var(--colors-red)',
      }
    })
  ]
}

Output:

:root {
  --colors-blue: 0,101,255;
  --colors-red: 255,0,0;
  --colors-green: 17,255,0
}

.text-white {
  --tw-text-opacity: 1;
  color: rgba(255, 255, 255, var(--tw-text-opacity))
}

.text-green {
  color: var(--colors-green)
}

.text-blue {
  --tw-text-opacity: 1;
  color: rgba(var(--colors-blue), var(--tw-text-opacity))
}

.text-red {
  --tw-text-opacity: 1;
  color: rgba(var(--colors-red), var(--tw-text-opacity))
}

.text-opacity-50 {
  --tw-text-opacity: 0.5
}

toBase

By default, variables are added to @tailwind base; styles. If you don't include @tailwind base; styles in your css, set the toBase option to false. In this case, the variables will be added to the @tailwind components; styles.

//...
plugins: [
  require('@mertasan/tailwindcss-variables')({
    toBase: false, // default: true
  })
]
//...

• tailwindcss.com - Functions and directives

API example for your own plugins

• Detailed Explanation

// tailwind.config.js
const plugin = require('tailwindcss/plugin')
const variablesApi = require('@mertasan/tailwindcss-variables/api')

let variableOptions = {
  variablePrefix: 'myplugin'
}

const pluginVariables = {
  DEFAULT: {
    colors: {
      primary: 'black',
      secondary: 'white',
      warning: 'orange',
    },
  },
}

const pluginDarkVariables = {
  DEFAULT: {
    colors: {
      primary: 'red',
      secondary: 'yellow',
      warning: 'green',
    },
  },
}

module.exports = {
  plugins: [
    plugin(function({ addComponents, config }) {

      addComponents(variablesApi.variables(pluginVariables, variableOptions))

      addComponents(variablesApi.darkVariables(pluginDarkVariables, variableOptions, config('darkMode'))) // darkMode: class

    })
  ]
}

Output:

:root {
  --myplugin-colors-primary: black;
  --myplugin-colors-secondary: white;
  --myplugin-colors-warning: orange
}

:root.dark {
  --myplugin-colors-primary: red;
  --myplugin-colors-secondary: yellow;
  --myplugin-colors-warning: green
}

API component helper

You can also use tailwindcss-variables plugin API to register your components.

// tailwind.config.js
const plugin = require('tailwindcss/plugin')
const variablesApi = require('@mertasan/tailwindcss-variables/api')

let variableOptions = {
  variablePrefix: 'myplugin'
}

const pluginVariables = {
  DEFAULT: {
    colors: {
      primary: 'black',
      secondary: 'white',
      warning: 'orange',
    },
  },
}

const pluginDarkVariables = {
  DEFAULT: {
    colors: {
      primary: 'red',
      secondary: 'yellow',
      warning: 'green',
    },
  },
}

module.exports = {
  plugins: [
    plugin(function({ addComponents, config }) {
      const formComponents = {
        select: {
          DEFAULT: {
            backgroundColor: 'var(--myplugin-colors-primary)',
          },
          multi: {
            '&.default-multi': {
              backgroundColor: 'var(--myplugin-colors-secondary)',
            },
            '&.other-multi': {
              backgroundColor: 'var(--myplugin-colors-warning)',
            },
          },
        },
      }

      addComponents(variablesApi.variables(pluginVariables, variableOptions))

      addComponents(variablesApi.darkVariables(pluginDarkVariables, variableOptions, config('darkMode'))) // darkMode: class

      // Automatically register components via API.
      addComponents(variablesApi.getComponents('.form', formComponents))
    })
  ]
}

Output:

:root {
  --myplugin-colors-primary: black;
  --myplugin-colors-secondary: white;
  --myplugin-colors-warning: orange;
}

:root.dark {
  --myplugin-colors-primary: red;
  --myplugin-colors-secondary: yellow;
  --myplugin-colors-warning: green;
}

.form-select {
    background-color: var(--myplugin-colors-primary);
}

.form-select.default-multi {
    background-color: var(--myplugin-colors-secondary);
}

.form-select.other-multi {
    background-color: var(--myplugin-colors-warning);
}

Detailed example of the API

What are the advantages?

Imagine you are creating a form builder (PHP) package for Laravel. In this case, I am sure there will be a lot of styles to customize. Nonetheless, one of the most necessary things is the colors! You'll develop the components with the colors you pick out. Of course these colors can be customized with the vendor:publish command but you can make it simpler for everyone. Users can customize the colors for their own likings and if they wish they can also configure your plugin for the dark mode as well. This way, users don't have to alter the .css or .blade.php files for some small and simple customizations. Thus, they can use your package with up to date components and can adapt to future version updates. If you have read this statement, it means that now you know why this plugin came about. :)

What are the disadvantages?

If you have any ideas, please don't refrain to send a PR.

Resources on this example:

• Source
• test

Your own plugin themes:

// myplugin/themes.js
module.exports = (theme) => ({
  themes: {
    DEFAULT: {
      colors: {
        primary: 'black',
        secondary: 'white',
        warning: 'orange',
      },
    }
  }
})

Your own plugin components:

// myplugin/components.js
module.exports = (theme) => ({
  select: {
    DEFAULT: {
      backgroundColor: 'var(--forms-colors-primary)',
    },
    multi: {
      '.default-multi': {
        backgroundColor: 'var(--forms-colors-secondary)',
      },
      '.other-multi': {
        backgroundColor: 'var(--forms-colors-warning)',
      },
    },
  },
})

Your own plugin source:

// myplugin/index.js
const plugin = require('tailwindcss/plugin')
const _ = require('lodash')
const variablesApi = require('@mertasan/tailwindcss-variables/api')
const pluginComponents = require('./components')
const pluginThemes = require('./themes')

module.exports = plugin.withOptions(
  function (options) {
    return function ({addComponents, theme, config}) {

      let variableOptions = {
        variablePrefix: theme('myPlugin.prefix', 'forms')
      };

      addComponents(variablesApi.variables(_.merge(pluginThemes(theme).themes, {DEFAULT: theme('myPlugin.options', {})}), variableOptions))

      let darkVariables = theme('myPlugin.darkOptions', {});
      if (!_.isEmpty(darkVariables)) {
        addComponents(variablesApi.darkVariables(darkVariables, variableOptions, config('darkMode')))
      }

      // Automatically register components via API.
      addComponents(variablesApi.getComponents('.form', pluginComponents(theme)))

    }
  }
)

User config: (tailwind.config.js)

// tailwind.config.js
module.exports = {
  theme: {
    myPlugin: {
      options: {
        colors: {
          primary: 'indigo', // custom color instead of default color
        }
      }
    },
  },
  plugins: [require('my-plugin')],
}

Output:

:root {
  --forms-colors-primary: indigo; /* <<< default color changed via root configuration */
  --forms-colors-secondary: white;
  --forms-colors-warning: orange;
}

.form-select {
    background-color: var(--forms-colors-primary);
}

.form-select .default-multi {
    background-color: var(--forms-colors-secondary);
}

.form-select .other-multi {
    background-color: var(--forms-colors-warning);
}

Based on these examples, it won't be necessary to publish extra .css files for your plugin styles and also, it won't be necessary for the users to sort out your style files to compile your packages.

Examples and tests

I have prepared examples on both helping with the usage and for testing all of the features that's being offered to make sure it works just fine.

Source	State
Examples
Plugin API Examples
Tests

Documents on examples and tests are re-organized on pull-request, push, release and etc. events. For this reason, file paths like require(../index) have been used on the example files. If you were to use the examples, you need to change the relevant lines as require('@mertasan/tailwindcss-variables').

If You Need Help

Please send any questions and issues through GitHub issues. I will try my best to help you.

Contribution

If you are to improve or/and add new features, please feel free to send pull-requests.

License

The MIT License (MIT). Please see License File for more information.