Stylelint Design System Rules

Stylelint design system rules enforce CSS standards and design token usage through automated style linting. These rules detect hardcoded values, forbidden properties, and non-compliant patterns in stylesheets and CSS-in-JS code. Integrating Stylelint with design system rules catches style drift during development.

What Are Stylelint Design System Rules

Stylelint design system rules are configurations and custom rules that extend Stylelint to check design system compliance in CSS, Sass, Less, and CSS-in-JS code. While Stylelint includes rules for general CSS quality, design system rules focus on organizational standards: token usage, allowed values, property restrictions, and naming conventions.

Stylelint rules operate on CSS regardless of where it appears. Rules can check standalone CSS files, Sass or Less files, CSS modules, styled-components, Emotion, and other CSS-in-JS approaches. This comprehensive coverage ensures style compliance across different styling methodologies.

How Stylelint Design System Rules Work

Built-in rules provide significant design system value with configuration. The declaration-property-value-allowed-list rule restricts which values are allowed for specific properties, enabling token enforcement. The color-no-hex rule disallows hex colors, requiring color tokens. The unit-allowed-list rule restricts units to those used in the token system. Configuration of built-in rules addresses many common needs.

Custom rules extend Stylelint for organization-specific needs. Custom rules use Stylelint’s PostCSS-based API to traverse and analyze CSS ASTs. Rules can check complex patterns that built-in rules cannot express, such as validating that custom property names follow naming conventions or that component selectors match expected patterns.

Plugin packages bundle related rules for distribution. Design system teams can create Stylelint plugins containing their custom rules and recommended configurations. Published plugins enable consistent enforcement across all projects consuming the design system.

Configuration files specify which rules apply and how. Stylelint configurations can extend from plugin-provided presets and override specific rules. Configuration hierarchies allow organization-wide base configurations with project-specific adjustments. This flexibility accommodates varying needs across teams and projects.

Integration mirrors other linters. IDE extensions display violations during editing. Git hooks catch violations before commits. CI pipelines enforce compliance. Consistent integration ensures violations are caught regardless of developer tooling choices.

Key Considerations

• CSS-in-JS support requires appropriate Stylelint syntax parsers
• Some design token patterns are difficult to express as Stylelint rules
• Performance matters for large stylesheets; rules should be efficient
• False positives from overly strict rules frustrate developers
• Rule severity should match violation importance

Common Questions

What Stylelint rules are most valuable for design system compliance?

Several rule categories provide significant value. Color restrictions using color-no-hex, color-named, or declaration-property-value-allowed-list enforce color token usage. Unit restrictions using unit-allowed-list limit measurements to token-compatible units. Property restrictions using declaration-property-value-allowed-list can require specific properties use only certain value patterns. Selector restrictions using selector-class-pattern enforce naming conventions that indicate design system alignment. Custom property rules using custom-property-pattern validate that CSS variables follow expected naming. Scale restrictions can ensure values like font sizes and spacing use only approved values from design scales.

How should organizations implement Stylelint for design systems?

Implementation typically follows a progression. Start by auditing current stylesheets to understand prevalent patterns and common violations. Enable rules gradually, beginning with uncontroversial checks and expanding as teams adapt. Use warnings before errors for new rules to provide adjustment time. Create clear documentation explaining what rules enforce and why. Provide guidance on addressing common violations. Establish feedback channels for developers to report problematic rules or request exceptions. Monitor violation metrics to track compliance improvement over time. Maintain rules as design systems evolve; rule changes should accompany standard changes.

Summary

Stylelint design system rules enforce CSS standards and token usage through built-in rules with design-system-focused configuration and custom rules for organization-specific needs. Rules can check CSS in all forms including preprocessors and CSS-in-JS through appropriate syntax parsers. Valuable rules address color restrictions, unit limitations, property value constraints, selector patterns, and custom property naming. Implementation should progress gradually with clear documentation, developer feedback channels, and ongoing maintenance as standards evolve.