Overlays & actionsExplore · Adapt · Compose
Dropdown
Context menu from a trigger — dismiss layer, positioning, asChild trigger, submenus, shortcuts, checkbox and radio items (shadcn Dropdown Menu pattern). Reveal the right amount of context without losing the user's place in the interface. Keep the trigger, content and dismissal behavior working as one interaction. 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 @/components/kamod-ui/dropdown 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
Import Dropdown primitives from @/components/kamod-ui/dropdown.
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
Use DropdownTrigger to toggle, DropdownContent for the panel (side, align, sideOffset). Optional DropdownSub / DropdownSubTrigger / DropdownSubContent for nested menus; DropdownSubContent supports side="inline-end" (default) or side="inline-start" to open toward the inline end or start (use inline-start when the trigger is near the viewport edge to avoid horizontal page scroll). Checkbox and radio items do not use DropdownItem’s auto-close behavior where noted.
import { Dropdown } from "@/components/kamod-ui/dropdown";Choose a complete composition from the examples below; required child components and props vary by pattern.
Component examples & variants
Explore Dropdown in different contexts, from the starting pattern to the compositions below. Begin with Basic, 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
Default trigger styling and menu items.
import { Dropdown, DropdownContent, DropdownItem, DropdownTrigger } from "@/components/kamod-ui/dropdown";
export const Example = () => (
<Dropdown>
<DropdownTrigger>Open menu</DropdownTrigger>
<DropdownContent>
<DropdownItem>Profile</DropdownItem>
<DropdownItem>Settings</DropdownItem>
</DropdownContent>
</Dropdown>
);Trigger asChild
Use a Button (or other element) as the trigger.
Groups, shortcuts, icons
Labels, separators, keyboard hints, and leading icons.
Checkbox items
Toggle state without closing the root menu.
Radio group
Single selection; menu closes after choosing (DropdownRadioItem).
Positioning
side, align, and sideOffset on DropdownContent.
Props and data
Configure Dropdown 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.Dropdown
Dropdown component props and accepted values.
| Prop / type | Description |
|---|---|
defaultOpen | Documented defaultOpen option for Dropdown. Check its type alongside the usage examples before supplying a value. Documented default |
DropdownTrigger asChild | Documented DropdownTrigger asChild option for Dropdown. Check its type alongside the usage examples before supplying a value. Documented default |
DropdownContent forceMount | Documented DropdownContent forceMount option for Dropdown. Check its type alongside the usage examples before supplying a value. Documented default |
DropdownContent side | Documented DropdownContent side option for Dropdown. Check its type alongside the usage examples before supplying a value. Documented default |
DropdownContent align | Documented DropdownContent align option for Dropdown. Check its type alongside the usage examples before supplying a value. Documented default |
DropdownContent sideOffset | Documented DropdownContent sideOffset option for Dropdown. Check its type alongside the usage examples before supplying a value. Documented default |
DropdownItem variant | Documented DropdownItem variant option for Dropdown. Check its type alongside the usage examples before supplying a value. Documented default |
DropdownItem inset | Documented DropdownItem inset option for Dropdown. Check its type alongside the usage examples before supplying a value. Documented default |
DropdownLabel inset | Documented DropdownLabel inset option for Dropdown. 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.
DropdownContextValueopen, setOpen, triggerId, contentId, rootRef, triggerRef, contentRefDropdownPropsDropdownCheckboxItemPropsDropdownContentPropsDropdownGroupPropsDropdownItemSharedPropsDropdownItemPropsDropdownLabelPropsDropdownPortalPropsDropdownRadioGroupPropsDropdownRadioItemPropsvalueDropdownSeparatorPropsDropdownShortcutPropsDropdownSubPropsDropdownSubContentPropsDropdownSubTriggerPropsDropdownTriggerPropsDropdownRadioContextValuevalue, setValueDropdownSubContextValueopen, setOpenAccessibility
Build the complete interaction, including the parts outside Dropdown. 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
DropdownTrigger exposes aria-haspopup="menu", expanded state and the controlled content ID. Content and items use menu roles, including checked states for checkbox and radio items. Escape closes the menu and returns to its trigger.
Labels and relationships
Name the trigger by its action scope, such as Invoice actions, and use specific item text. Keep shortcuts supplementary: the item name must describe the action even when the keyboard hint is omitted.
Keyboard and focus
Exercise the shipped menu keyboard behavior with enabled, disabled and nested items. Reuse its item components and focus handling rather than installing a second document-level listener. Verify the complete path through a submenu and back to its parent.
States and integration details
Menu roles promise more than a visually positioned list. Test arrow-key behavior and screen-reader output in the exact composition rather than assuming parity with another library. For ordinary site destinations, consider navigation links instead of application-menu semantics.
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.
- Open, choose an action and dismiss without a pointer; confirm return focus.
- Check selected/checked menu items and disabled actions with assistive technology.
- Traverse nested menus and long localized labels without losing focus or triggering the wrong action.
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 Dropdown 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
Keep trigger and content within the component's documented composition. Give destructive actions a clear consequence and an explicit confirmation. Let the primitive manage focus and dismissal instead of adding a second document-level keyboard handler.
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 Dropdown.
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
- Open with the keyboard, move through the content and verify focus returns to a sensible trigger when closed.
- Test Escape, outside interaction and nested overlays according to the component's documented behavior.
- Check long titles and content on a small screen; the important action must remain reachable without clipping.
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
Dropdown 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 Dropdown 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.