Composition & layoutExplore · Adapt · Compose
cn Utility
cn combines clsx for conditional class lists with tailwind-merge to resolve conflicting Tailwind utilities. Build a clear hierarchy with reusable structure, consistent spacing and semantic surfaces. Keep layout decisions close to the content they organize. Explore the live examples, inspect their source and choose the composition that fits your interface before connecting it to your application's data.
The examples use @kamod-ch/ui/utils in a Preact project. Follow the live result and its source together: compare supported options in the API reference, refine presentation with the component styles guide, and use shared theme tokens for consistent colors and surfaces. Preserve keyboard behavior and meaningful labels as you replace the sample content.
In this guide 7 sections
Installation
cn ships with @kamod-ch/ui — no separate package or install step. Add @kamod-ch/ui once and import cn from @kamod-ch/ui/utils. You can also import it from the package root: import { cn } from "@kamod-ch/ui".
pnpm add @kamod-ch/uiThe @/components/kamod-ui/… imports in these examples refer to local source files. Configure that alias when copying source, or use the corresponding exports from @kamod-ch/ui when installing the package. Connect the global theme CSS and Tailwind source detection before your first render.
Usage
Pass base classes first, then conditional values, arrays, or object maps. Put consumer class props last so callers can override defaults. clsx handles falsy values; tailwind-merge keeps the last conflicting utility (for example px-4 wins over px-2).
import { cn } from "@kamod-ch/ui/utils";cn("rounded-lg border bg-background p-4", className)Component examples & variants
Explore cn Utility in different contexts, from the starting pattern to the compositions below. Begin with Basic classes, then compare the examples that match your content, state and layout. These are working patterns to adapt, not a list of interchangeable variant values: check the API reference before using a prop or combining behaviors. Look at the surrounding labels, supporting text and spacing as well as the component itself.
Read the result and its implementation together. Use each showcase’s Code view to inspect imports and composition, or its Prompt view to prepare a setup or adaptation brief. Try the narrow preview and local theme controls before connecting real data, and use Reset to return an example to its initial state. Keep layout changes in class utilities where appropriate; follow the component styles guide for hierarchy and the theming guide for shared surfaces and colors. The accessibility notes explain what to preserve when making those changes.
Basic classes
Join static Tailwind classes into one string.
import { cn } from "@kamod-ch/ui/utils";
cn("rounded-lg border bg-background p-4");Conditional classes
clsx-style conditionals omit falsy values — booleans, null, and undefined are ignored.
Arrays and objects
Arrays and object maps follow clsx semantics: object keys are included when their value is truthy.
Overriding defaults
tailwind-merge resolves conflicting utilities so later inputs win — useful when defaults meet consumer overrides.
Preact component
Kamod UI components accept class (not className). Pass consumer classes last in cn() so props override built-in styles.
With tailwind-variants
Library components use cn(variantFn({ ... }), className) so variant classes and consumer overrides compose safely.
clsx vs cn
clsx concatenates class names but keeps every token. cn runs clsx first, then tailwind-merge removes conflicting utilities from the result.
Props and data
Configure cn Utility using the contracts below. Read the documented options alongside the source definitions to understand which values your application supplies and which details the component owns. Start with a prop or helper, then follow its type link to inspect the declaration without leaving the page.
Props, slots and variants for this component.
TypeScript source at build time. Props inherited through HTMLAttributes, Omit or variant helpers remain references in those declarations; their fields are not flattened here. Match the reference to your installed version, and check a package’s exports before writing an import type. A type exported by a source file is not necessarily re-exported by @kamod-ch/ui.TypeScriptComponent props
? means a field can be omitted; it does not promise a fallback value. Existing documented defaults remain alongside the descriptions. For callbacks, check the argument and return types before connecting your own state or services.cn Utility
cn Utility component props and accepted values.
| Prop / type | Description |
|---|---|
...inputs | Documented ...inputs option for cn Utility. Check its type alongside the usage examples before supplying a value. Documented default |
returns | Documented returns option for cn Utility. Check its type alongside the usage examples before supplying a value. Documented default |
Data type reference
Expand a card to inspect and copy the exact declaration. The code header identifies its repository file; follow imported or inherited types in the implementation source when you need the complete dependency chain. Required-field summaries cover fields declared directly in that type. Source-only helpers and inferred schema outputs describe the local implementation, not additional props you can pass to every component.
This implementation does not declare a separate props or data type in its component folder. Follow the source reference and documented signatures above; no extra type is implied by the examples.
Accessibility
Build the complete interaction, including the parts outside cn Utility. The notes below distinguish the current implementation from the labels, content and behavior your application supplies. Start with the live preview, check the props and data reference, and test the finished composition with real content rather than assuming that an unchanged visual example covers every use case.
Built-in behavior and defaults
cn combines class names and has no DOM, roles, focus behavior or accessible name. Its accessibility impact comes from the styles you compose on actual controls and content.
Labels and relationships
Keep labels and ARIA attributes on the rendered element; a class-name helper cannot create their relationships. Make state classes follow the same state value used by semantic attributes so visual and announced behavior do not disagree.
Keyboard and focus
Preserve focus-visible styles when merging overrides and keep disabled styling aligned with actual disabled behavior. Use the helper to express conditional presentation without replacing native interaction with click-only wrappers.
States and integration details
A later class can hide content, suppress a focus ring or remove a useful contrast treatment. Review the final computed styles rather than assuming all source classes remain effective after merging.
Verify the complete interaction
Check behavior as well as markup. Work through these scenarios in the application where the component will be used. Automated checks can help find structural problems; also review the reading experience with a screen reader, keyboard focus and the actual feedback from your application.
- Inspect the final focused, disabled and invalid control after class overrides.
- Compare visual state against checked, pressed, expanded or invalid semantics as applicable.
- Test light/dark themes and reduced motion with the fully composed class list.
Recheck the result after changing theme tokens, translations or class overrides. Include text enlargement, narrow layouts and reduced-motion settings where animation is present. Inspect the component source when a behavior differs from your expectation; a role or state attribute does not implement keyboard interaction by itself.
For background, read the WAI-ARIA authoring guidance and keyboard interface guidance. These explain the patterns; verify browser and assistive-technology behavior for the implementation and audience you actually support.
Build it into your interface
Use the cn Utility examples as a starting point, then review the behavior in the context of your own screen. Layout, state and content should work together.
Connect the behavior
Start from the smallest example that expresses your intent. Keep document order meaningful, use native semantics for headings and landmarks, and let the parent layout own page-level spacing. Avoid nesting interactive elements just to match a visual treatment.
Copy the composition, then connect its intent. Replace sample records and callbacks with your own data flow. For options such as value, defaultValue, open or onChange, use only those documented in this component's API; different components expose different contracts.
Give each piece of state one owner. Keep a temporary selection inside the interface when nothing else needs it; lift shared values into a parent when other controls depend on them. Read the prop reference before combining controlled values with defaults. A default normally initializes a control; it is not a substitute for updating its current value.
Connect requests in an event handler or your application’s data layer, never as a side effect of rendering. Keep pending, completed and failed outcomes distinct, preserve useful input after an error, and offer a clear recovery action. If the integration subscribes to an external source, remove that subscription when its owner unmounts; cancel or ignore obsolete requests so an earlier response cannot replace newer results.
Start with the live preview, then exercise the same interaction with your actual data. The type definitions describe accepted values; they do not implement persistence, navigation or server-side validation for you. Keep those responsibilities in the application that composes the UI.
Refine the presentation
Let a parent own the surrounding spacing. Keep related elements together with gap and use semantic surface/foreground pairs so the composition follows the active theme. The wrapper below changes the surrounding layout without assuming extra props on cn Utility.
import type { ComponentChildren } from "preact";
export function ExampleSurface({ children }: { children: ComponentChildren }) {
return (
<div class="grid min-w-0 gap-4 rounded-lg border border-border bg-card p-4 text-card-foreground sm:p-6">
{children}
</div>
);
}Put the chosen example inside ExampleSurface, then refine supported variants and sizes using the API above. For application-wide changes, adjust theme tokens instead of repeating fixed colors. See Component styles for hierarchy, density and focus treatments.
Review the complete interaction
- Review long content, empty content and narrow containers without relying on a fixed height.
- Check text zoom, visible focus and contrast in light and dark appearances.
- Use documented extension points and verify class overrides do not erase essential interaction styles.
The preview's narrow control changes its container width. Also resize the browser when checking viewport-based Tailwind utilities such as sm: and md:, and test overlays in the full page where their portals render.
Compose a complete interface
cn Utility is one part of the interaction. Choose companion components for the information or actions that still need a place on the screen. The references below are suggestions to compose deliberately, not extra dependencies you must add to every example.
Keep one source of truth for the operation and let each component communicate a different part of it. For example, waiting, no results and failure need different explanations. Avoid showing contradictory states together, and keep recovery actions close to the message that explains them.
Start with the smallest composition that explains the task. Browse the component library for individual controls or the block collections for complete layouts. Reuse shared theme tokens so these pieces feel consistent in light and dark mode.
Sources & design references
Follow cn Utility from its implementation to the ideas behind your own composition. Start with the local API, explore a visual direction, then bring the result back to your app’s shared styles.
Bring it back to your app
A reference becomes useful when it fits your real content. Work through these decisions in order:
- Keep the behavior grounded. Start with the interactive examples, then connect your data and callbacks using the integration guidance. Preserve labels, keyboard access and disabled states as you change the presentation.
- Make the styling repeatable. Use the styles guide for local
classadjustments and theming documentation for shared color decisions. Keep semantic surface and foreground pairs together in both light and dark mode. - Check the complete screen. See how components combine in the block collections, then try long labels, loading states and narrow layouts in your own composition. The Theme Toggle guide helps you expose a scheme switch in the finished interface.