eslint-plugin-vanilla-extract/README.md

# @antebudimir/eslint-plugin-vanilla-extract

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An ESLint plugin for enforcing best practices in [vanilla-extract](https://github.com/vanilla-extract-css/vanilla-extract) CSS styles, including CSS property ordering and additional linting rules. Available presets are for alphabetical and [concentric](https://rhodesmill.org/brandon/2011/concentric-css/) CSS ordering. The plugin also supports a custom group ordering option based on groups available in [concentric CSS](src/css-rules/concentric-order/concentric-groups.ts).

## Demo

![Plugin Demo](https://github.com/user-attachments/assets/93ba118d-84df-4da0-ac68-fdb429e581d6)

## Features

- Enforces CSS property ordering in vanilla-extract style objects with two available presets:
  - Alphabetical ordering for clean, predictable style organization
  - Concentric ordering for logical, outside-in property arrangement
- Custom group ordering option for more fine-grained control
- Built for ESLint 9 flat config system
- Provides auto-fix capability to automatically sort properties
- Handles multiple vanilla-extract APIs (style, styleVariants, recipe, globalStyle, etc.)
- Handles complex cases like nested objects, arrays of styles, and pseudo selectors
- Works with camelCase properties as used in vanilla-extract
- Additional linting rules for enhanced code quality (see roadmap for upcoming features)

## Requirements

- ESLint 9.0.0 or higher
- Node.js 18.18.0 or higher
- ESM (ECMAScript Modules) only

## Installation

```bash
# Using npm
npm install --save-dev @antebudimir/eslint-plugin-vanilla-extract

# Using yarn
yarn add --dev @antebudimir/eslint-plugin-vanilla-extract

# Using pnpm
pnpm add -D @antebudimir/eslint-plugin-vanilla-extract
```

## Usage

**Note: This plugin is ESM-only.** It must be used with ESM configurations and can't be used with CommonJS `require()`.

### ESLint Flat Config (ESLint 9+)

Create or update your `eslint.config.js` or `eslint.config.mjs` file:

```typescript
import vanillaExtract from '@antebudimir/eslint-plugin-vanilla-extract';

export default [
  {
    files: ['**/*.css.ts'],
    ignores: ['src/**/theme-contract.css.ts'],
    plugins: {
      'vanilla-extract': vanillaExtract,
    },
    rules: {
      // 'vanilla-extract/alphabetical-order': 'warn',
      // OR
      // 'vanilla-extract/concentric-order': 'warn',
      // OR
      'vanilla-extract/custom-order': [
        'warn',
        {
          groupOrder: ['font', 'dimensions', 'margin', 'padding', 'position', 'border'], // example group order
          // optional
          sortRemainingProperties: 'concentric', // 'alphabetical' is default
        },
      ],
    },
  },
];
```

## Rules

### vanilla-extract/alphabetical-order

This rule enforces that CSS properties in vanilla-extract style objects follow alphabetical ordering.

```typescript
// ❌ Incorrect
import { style } from '@vanilla-extract/css';

export const myStyle = style({
  display: 'flex',
  justifyContent: 'center',
  alignItems: 'center',
  height: 19,
  marginBottom: 1,
  marginLeft: 2,
});

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

export const myStyle = style({
  alignItems: 'center',
  display: 'flex',
  height: 19,
  justifyContent: 'center',
  marginBottom: 1,
  marginLeft: 2,
});
```

### vanilla-extract/concentric-order

This rule enforces that CSS properties in vanilla-extract style objects follow the concentric CSS ordering pattern,
which organizes properties from outside to inside.

```typescript
// ❌ Incorrect
import { style } from '@vanilla-extract/css';

export const myStyle = style({
  color: 'red',
  display: 'flex',
  position: 'relative',
  padding: '10px',
  margin: '20px',
});

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

export const myStyle = style({
  position: 'relative',
  display: 'flex',
  margin: '20px',
  padding: '10px',
  color: 'red',
});
```

### vanilla-extract/custom-order

The `vanilla-extract/custom-order` rule enables you to enforce a custom ordering of CSS properties in your vanilla-extract styles. You can specify an array of property groups in your preferred order, and the rule will ensure that properties within these groups are sorted according to their position in the concentric CSS model.

Key features of this rule include:

1. Custom group ordering: Define your preferred order of CSS property groups.
2. Handling of unspecified groups: All groups not included in the custom array will have their properties sorted after the last specified group.
3. Flexible sorting options: You can choose to sort remaining properties either alphabetically or following the concentric CSS order by setting the `sortRemainingProperties` option to 'alphabetical' or 'concentric' respectively.

Default behavior:

- If not set, `sortRemainingProperties` defaults to 'alphabetical'.
- If no `groupOrder` is specified or an empty array is provided, the rule will default to sorting all properties alphabetically, and `sortRemainingProperties` will be ignored even if set.

To configure the rule, add it to your ESLint configuration file with your desired options. You can customize the `groups` array to include any number of available CSS property groups you want to enforce, with a minimum of one group required.

```typescript
// ❌ Incorrect (Unordered)
import { style } from '@vanilla-extract/css';

export const myStyle = style({
  color: 'blue',
  padding: '10px',
  fontFamily: 'Arial, sans-serif',
  margin: '20px',
  width: '200px',
  border: '1px solid black',
  display: 'flex',
});

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

export const myStyle = style({
  // font group
  fontFamily: 'Arial, sans-serif',
  color: 'blue',

  // dimensions group
  width: '200px',

  // margin group
  margin: '20px',

  // padding group
  padding: '10px',

  // display group
  display: 'flex',

  // border group
  border: '1px solid black',
});
```

### vanilla-extract/no-empty-style-blocks

This rule detects and prevents empty style blocks in vanilla-extract stylesheets. It helps maintain cleaner codebases by eliminating empty style definitions that often result from incomplete refactoring or forgotten implementations.

```typescript
// ❌ Incorrect
import { style } from '@vanilla-extract/css';

export const emptyStyle = style({});

export const nestedEmpty = style({
  color: 'blue',

  ':hover': {},
  '@media': {
    '(min-width: 768px)': {},
  },
});

export const recipeWithEmptyVariants = recipe({
  base: { color: 'black' },
  variants: {},
});

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

export const nestedEmpty = style({
  color: 'blue',
});

export const recipeWithEmptyVariants = recipe({
  base: { color: 'black' },
});
```

## Font Face Declarations

For `fontFace` and `globalFontFace` API calls, all three ordering rules (alphabetical, concentric, and custom) enforce the same special ordering:

1. The `src` property always appears first
2. All remaining properties are sorted alphabetically

This special handling is applied because:

- The `src` property is the most critical property in font face declarations
- Consistent ordering improves readability for these specific APIs
- Font-related properties are specialized and benefit from standardized ordering

```typescript
// ✅ Correct ordering for font faces
export const theFont = fontFace({
  src: ['url("/fonts/MyFont.woff2") format("woff2")', 'url("/fonts/MyFont.woff") format("woff")'],
  ascentOverride: '90%',
  descentOverride: '10%',
  fontDisplay: 'swap',
  fontFeatureSettings: '"liga" 1',
  fontStretch: 'normal',
  // ...other properties in alphabetical order
});
```

Opinionated, but it is what it is. If someone has a suggestion for a better ordering, let me know!

## Concentric CSS Model

Here's a list of all available groups from the provided [concentricGroups](src/css-rules/concentric-order/concentric-groups.ts) array:

1. boxSizing
2. position
3. display
4. flex
5. grid
6. alignment
7. columns
8. transform
9. transitions
10. visibility
11. shape
12. margin
13. outline
14. border
15. boxShadow
16. background
17. cursor
18. padding
19. dimensions
20. overflow
21. listStyle
22. tables
23. animation
24. text
25. textSpacing
26. font
27. content
28. counters
29. breaks

These groups represent different categories of CSS properties, organized in a concentric order from outside to inside. Each group contains related CSS properties that affect specific aspects of an element's styling and layout.

## Roadmap

The roadmap outlines the project's current status and future plans:

### Completed Milestones

- Initial release with support for alphabetical, concentric, and custom group CSS ordering.
- Auto-fix capability integrated into ESLint.
- Support for multiple vanilla-extract APIs (e.g., `style`, `styleVariants`, `recipe`, `globalStyle`, `fontFace`, etc.).
- `no-empty-style-blocks` rule to disallow empty blocks.
- Comprehensive rule testing.

### Current Work

- Setting up recommended ESLint configuration for the plugin.

### Upcoming Features

- `no-unknown-units` rule to disallow unknown units.
- `no-number-trailing-zeros` rule to disallow trailing zeros in numbers.
- `no-zero-unit` rule to disallow units when the value is zero.
- `no-px-unit` rule to disallow use of `px` units with configurable whitelist.
- `prefer-logical-properties` rule to enforce use of logical properties.
- `prefer-theme-tokens` rule to enforce use of theme tokens instead of hard-coded values when available.
- `no-global-style` rule to disallow use of `globalStyle` function.
- Option to sort properties within user-defined concentric groups alphabetically instead of following the concentric order. **Note**: This feature will only be implemented if there's sufficient interest from the community.

## Contributing

All well-intentioned contributions are welcome, of course! Please feel free to submit a Pull Request or get in touch via
GitHub issues.

## License

This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.