Linting your CSS to limit yourself to a defined subset of values.

CSS can get unweildy sometimes, as new features are added and new people join the team. It's hard to be consistent, and that's why utility/functional CSS libraries like Tailwind are growing in popularity. SubsetCSS helps aleviate this problem by enforcing your CSS to a predefined amount of values, keeping everyone on the same page as a project evolves.

Note: in development

yarn add -D subsetcss stylelint

Add a stylelint.config.js file with the following config:

let config = require('./.subsetcss');

module.exports = {
  plugins: ['subsetcss'],
  rules: {
    'subsetcss/config': [true, config],
  },
};

Create a .subsetcss.js file with content like:

module.exports = {
  subsets: {
    'font-size': [
      '.75rem', // 12px
      '.875rem', // 14px
      '1rem', // 16px
      '1.125rem', // 18px
      '1.25rem', // 20px
      '1.5rem', // 24px
      '1.875rem', // 30px
      '2.25rem', // 36px
      '3rem', // 48px
    ],
    'border-width': (key, value) => ['0', '1px', '2px', '3px'],
    'border-color': [
      'transparent',
      '#22292f',
      '#3d4852',
      '#606f7b',
      '#8795a1',
      '#b8c2cc',
    ],
    'border-style': ['solid'],
  },
  '@media': [
    {
      // optional
      type: 'print',
      // optional
      params: {
        'max-width': ['400px', '768px'],
      },
      subsets: {
        'font-size': [
          '1rem', // 16px
          '1.125rem', // 18px
          '1.25rem', // 20px
          '1.5rem', // 24px
          '1.875rem', // 30px
        ],
      },
    },
  ],
};

Here's an example config based on TailwindCSS styles https://gist.github.com/knownasilya/0ceb5fe6c02d558f2e908516dc1551bd

You can run with yarn stylelint "src/styles/*.css". Feel free to add to your npm scripts or setup with any intermediate tools.

• css variables: 'font-color': ['var(--text-color, black)']
• sass variables: 'font-color': ['$text-color']
• less variables: 'font-color': ['@text-color']

Use https://polished.js.org/docs/#modularscale or something similar.

'font-size': Array.from({ length: 5 }, (_v, index) => polished.modularScale(index)),

First value is the step, second the starting value (defaults to '1em') and third is the modular scale, which can be one of the values defined here: https://polished.js.org/docs/#modularscaleratio

You can preview modular scales here: https://www.modularscale.com/

Use https://github.com/TypeCtrl/tinycolor#color-combinations or something similar.

const colors = new TinyColor('#f00').polyad(4);
// later
'color': colors.map(t => t.toHexString())

Have a look at https://github.com/subsetcss/config-helpers for official helper functions to help build out your config.

See the Contributing guide.