Listbox
A list of options that can be selected by the user.
Overview
The Listbox component provides users with a selectable list of options. It's designed to offer an enhanced selection experience with features like typeahead search, keyboard navigation, and customizable grouping. This component is particularly useful for scenarios where users need to choose from a predefined set of options, offering more functionality than a standard select element.
Key Features
- Typeahead Search: Users can quickly find options by typing
- Keyboard Navigation: Full support for keyboard interactions, allowing users to navigate through options using arrow keys, enter to select, and more.
- Grouped Options: Ability to organize options into logical groups, enhancing readability and organization of large option sets.
- Scroll Management: Includes scroll up/down buttons for easy navigation in long lists.
- Accessibility: Built-in ARIA attributes and keyboard support ensure compatibility with screen readers and adherence to accessibility standards.
- Portal Support: Option to render the listbox content in a portal, preventing layout issues in complex UI structures.
Architecture
The Listbox component is composed of several sub-components, each with a specific role:
- Root: The main container component that manages the state and context for the combobox.
- Trigger: The button or element that opens the dropdown list.
- Portal: Responsible for portalling the dropdown content to the body or a custom target.
- Group: A container for grouped items, used to group related items.
- GroupHeading: A heading for a group of items, providing a descriptive label for the group.
- Item: An individual item within the list.
- Separator: A visual separator between items.
- Content: The dropdown container that displays the items. It uses Floating UI to position the content relative to the trigger.
- ContentStatic (Optional): An alternative to the Content component, that enables you to opt-out of Floating UI and position the content yourself.
- Arrow: An arrow element that points to the trigger when using the
Combobox.Content
component.
Structure
Here's an overview of how the Listbox component is structured in code:
Reusable Components
As you can see from the structure above, there are a number of pieces that make up the Listbox
component. These pieces are provided to give you maximum flexibility and customization options, but can be a burden to write out everywhere you need to use a listbox in your application.
To ease this burden, it's recommended to create your own reusable listbox component that wraps the primitives and provides a more convenient API for your use cases.
Here's an example of how you might create a reusable MyListbox
component that receives a list of options and renders each of them as an item.
You can then use the MyListbox
component throughout your application like so:
Managing Value State
Bits UI offers several approaches to manage and synchronize the Listbox's value state, catering to different levels of control and integration needs.
1. Two-Way Binding
For seamless state synchronization, use Svelte's bind:value
directive. This method automatically keeps your local state in sync with the component's internal state.
Key Benefits
- Simplifies state management
- Automatically updates
myValue
when the internal state changes (e.g., via clicking on an item) - Allows external control (e.g., selecting an item via a separate button)
2. Change Handler
For more granular control or to perform additional logic on state changes, use the onValueChange
prop. This approach is useful when you need to execute custom logic alongside state updates.
Use Cases
- Implementing custom behaviors on value change
- Integrating with external state management solutions
- Triggering side effects (e.g., logging, data fetching)
3. Fully Controlled
For complete control over the component's value state, use the controlledValue
prop. This approach requires you to manually manage the value state, giving you full control over when and how the component responds to value change events.
To implement controlled state:
- Set the
controlledValue
prop totrue
on theListbox.Root
component. - Provide a
value
prop toListbox.Root
, which should be a variable holding the current state. - Implement an
onValueChange
handler to update the state when the internal state changes.
When to Use
- Implementing complex open/close logic
- Coordinating multiple UI elements
- Debugging state-related issues
Note
While powerful, fully controlled state should be used judiciously as it increases complexity and can cause unexpected behaviors if not handled carefully.
For more in-depth information on controlled components and advanced state management techniques, refer to our Controlled State documentation.
Managing Open State
Bits UI offers several approaches to manage and synchronize the Listbox's open state, catering to different levels of control and integration needs.
1. Two-Way Binding
For seamless state synchronization, use Svelte's bind:open
directive. This method automatically keeps your local state in sync with the component's internal state.
Key Benefits
- Simplifies state management
- Automatically updates
myOpen
when the internal state changes (e.g., via clicking on the trigger/input) - Allows external control (e.g., opening via a separate button)
2. Change Handler
For more granular control or to perform additional logic on state changes, use the onOpenChange
prop. This approach is useful when you need to execute custom logic alongside state updates.
Use Cases
- Implementing custom behaviors on open change
- Integrating with external state management solutions
- Triggering side effects (e.g., logging, data fetching)
3. Fully Controlled
For complete control over the component's value state, use the controlledOpen
prop. This approach requires you to manually manage the value state, giving you full control over when and how the component responds to value change events.
To implement controlled state:
- Set the
controlledOpen
prop totrue
on theListbox.Root
component. - Provide an
open
prop toListbox.Root
, which should be a variable holding the current state. - Implement an
onOpenChange
handler to update the state when the internal state changes.
When to Use
- Implementing complex open/close logic
- Coordinating multiple UI elements
- Debugging state-related issues
Note
While powerful, fully controlled state should be used judiciously as it increases complexity and can cause unexpected behaviors if not handled carefully.
For more in-depth information on controlled components and advanced state management techniques, refer to our Controlled State documentation.
Opt-out of Floating UI
When you use the Listbox.Content
component, Bits UI uses Floating UI to position the content relative to the trigger, similar to other popover-like components.
You can opt-out of this behavior by instead using the Listbox.ContentStatic
component.
When using this component, you'll need to handle the positioning of the content yourself. Keep in mind that using Listbox.Portal
alongside Listbox.ContentStatic
may result in some unexpected positioning behavior, feel free to not use the portal or work around it.
Custom Anchor
By default, the Listbox.Content
is anchored to the Listbox.Trigger
component, which determines where the content is positioned.
If you wish to instead anchor the content to a different element, you can pass either a selector string or an HTMLElement
to the customAnchor
prop of the Listbox.Content
component.
What is the Viewport?
The Listbox.Viewport
component is used to determine the size of the content in order to determine whether or not the scroll up and down buttons should be rendered.
If you wish to set a minimum/maximum height for the select content, you should apply it to the Listbox.Viewport
component.
Scroll Up/Down Buttons
The Listbox.ScrollUpButton
and Listbox.ScrollDownButton
components are used to render the scroll up and down buttons when the select content is larger than the viewport.
You must use the Listbox.Viewport
component when using the scroll buttons.
Native Scrolling/Overflow
If you don't want to use the scroll buttons and prefer to use the standard scrollbar/overflow behavior, you can omit the Listbox.Scroll[Up|Down]Button
components and the Listbox.Viewport
component.
You'll need to set a height on the Listbox.Content
component and appropriate overflow
styles to enable scrolling.
Scroll Lock
By default, when a user opens the listbox, scrolling outside the content will be disabled. You can override this behavior by setting the preventScroll
prop to false
.
Highlighted Items
The Listbox component follows the WAI-ARIA descendant pattern for highlighting items. This means that the Listbox.Trigger
retains focus the entire time, even when navigating with the keyboard, and items are highlighted as the user navigates them.
Styling Highlighted Items
You can use the data-highlighted
attribute on the Listbox.Item
component to style the item differently when it is highlighted.
onHighlight / onUnhighlight
To trigger side effects when an item is highlighted or unhighlighted, you can use the onHighlight
and onUnhighlight
props.
API Reference
The root listbox component which manages & scopes the state of the listbox.
Property | Type | Description |
---|---|---|
type required | enum | The type of selection to use for the listbox. Default: undefined |
value $bindable | union | The value of the listbox. When the type is Default: undefined |
onValueChange | function | A callback that is fired when the listbox value changes. When the type is Default: undefined |
controlledValue | boolean | Whether or not the value is controlled or not. If Default: false |
open $bindable | boolean | The open state of the listbox menu. Default: false |
onOpenChange | function | A callback that is fired when the listbox menu's open state changes. Default: undefined |
controlledOpen | boolean | Whether or not the open state is controlled or not. If Default: false |
disabled | boolean | Whether or not the listbox component is disabled. Default: false |
name | string | The name to apply to the hidden input element for form submission. If provided, a hidden input element will be rendered to submit the value of the listbox. Default: undefined |
required | boolean | Whether or not the listbox menu is required. Default: false |
scrollAlignment | enum | The alignment of the highlighted item when scrolling. Default: 'nearest' |
loop | boolean | Whether or not the listbox menu should loop through items. Default: false |
children | Snippet | The children content to render. Default: undefined |
A button which toggles the listbox's open state.
Property | Type | Description |
---|---|---|
ref $bindable | HTMLButtonElement | The underlying DOM element being rendered. You can bind to this to get a reference to the element. Default: undefined |
children | Snippet | The children content to render. Default: undefined |
child | Snippet | Use render delegation to render your own element. See delegation docs for more information. Default: undefined |
Data Attribute | Value | Description |
---|---|---|
data-state | enum | The listbox's open state. |
data-disabled | '' | Present when the listbox is disabled. |
data-listbox-trigger | '' | Present on the trigger element. |
The element which contains the listbox's items.
Property | Type | Description |
---|---|---|
side | enum | The preferred side of the anchor to render the floating element against when open. Will be reversed when collisions occur. Default: bottom |
sideOffset | number | The distance in pixels from the anchor to the floating element. Default: 0 |
align | enum | The preferred alignment of the anchor to render the floating element against when open. This may change when collisions occur. Default: start |
alignOffset | number | The distance in pixels from the anchor to the floating element. Default: 0 |
arrowPadding | number | The amount in pixels of virtual padding around the viewport edges to check for overflow which will cause a collision. Default: 0 |
avoidCollisions | boolean | When Default: true |
collisionBoundary | union | A boundary element or array of elements to check for collisions against. Default: undefined |
collisionPadding | union | The amount in pixels of virtual padding around the viewport edges to check for overflow which will cause a collision. Default: 0 |
sticky | enum | The sticky behavior on the align axis. Default: partial |
hideWhenDetached | boolean | When Default: true |
updatePositionStrategy | enum | The strategy to use when updating the position of the content. When Default: optimized |
strategy | enum | The positioning strategy to use for the floating element. When Default: fixed |
preventScroll | boolean | When Default: false |
customAnchor | union | Use an element other than the trigger to anchor the content to. If provided, the content will be anchored to the provided element instead of the trigger. Default: null |
onEscapeKeydown | function | Callback fired when an escape keydown event occurs in the floating content. You can call Default: undefined |
escapeKeydownBehavior | enum | The behavior to use when an escape keydown event occurs in the floating content. Default: close |
onInteractOutside | function | Callback fired when an outside interaction event completes, which is either a Default: undefined |
onFocusOutside | function | Callback fired when focus leaves the dismissible layer. You can call Default: undefined |
interactOutsideBehavior | enum | The behavior to use when an interaction occurs outside of the floating content. Default: close |
onCloseAutoFocus | function | Event handler called when auto-focusing the content as it is closed. Can be prevented. Default: undefined |
preventOverflowTextSelection | boolean | When Default: true |
dir | enum | The reading direction of the app. Default: ltr |
loop | boolean | Whether or not the listbox should loop through items when reaching the end. Default: false |
forceMount | boolean | Whether or not to forcefully mount the content. This is useful if you want to use Svelte transitions or another animation library for the content. Default: false |
ref $bindable | HTMLDivElement | The underlying DOM element being rendered. You can bind to this to get a reference to the element. Default: undefined |
children | Snippet | The children content to render. Default: undefined |
child | Snippet | Use render delegation to render your own element. See delegation docs for more information. Default: undefined |
Data Attribute | Value | Description |
---|---|---|
data-state | enum | The listbox's open state. |
data-listbox-content | '' | Present on the content element. |
CSS Variable | Description |
---|---|
--bits-listbox-content-transform-origin | The transform origin of the listbox content element. |
--bits-listbox-content-available-width | The available width of the listbox content element. |
--bits-listbox-content-available-height | The available height of the listbox content element. |
--bits-listbox-anchor-width | The width of the listbox trigger element. |
--bits-listbox-anchor-height | The height of the listbox trigger element. |
The element which contains the listbox's items. (Static/No Floating UI)
Property | Type | Description |
---|---|---|
onEscapeKeydown | function | Callback fired when an escape keydown event occurs in the floating content. You can call Default: undefined |
escapeKeydownBehavior | enum | The behavior to use when an escape keydown event occurs in the floating content. Default: close |
onInteractOutside | function | Callback fired when an outside interaction event completes, which is either a Default: undefined |
onFocusOutside | function | Callback fired when focus leaves the dismissible layer. You can call Default: undefined |
interactOutsideBehavior | enum | The behavior to use when an interaction occurs outside of the floating content. Default: close |
onOpenAutoFocus | function | Event handler called when auto-focusing the content as it is opened. Can be prevented. Default: undefined |
onCloseAutoFocus | function | Event handler called when auto-focusing the content as it is closed. Can be prevented. Default: undefined |
trapFocus | boolean | Whether or not to trap the focus within the content when open. Default: true |
preventScroll | boolean | When Default: true |
preventOverflowTextSelection | boolean | When Default: true |
dir | enum | The reading direction of the app. Default: ltr |
loop | boolean | Whether or not the listbox should loop through items when reaching the end. Default: false |
forceMount | boolean | Whether or not to forcefully mount the content. This is useful if you want to use Svelte transitions or another animation library for the content. Default: false |
ref $bindable | HTMLDivElement | The underlying DOM element being rendered. You can bind to this to get a reference to the element. Default: undefined |
children | Snippet | The children content to render. Default: undefined |
child | Snippet | Use render delegation to render your own element. See delegation docs for more information. Default: undefined |
Data Attribute | Value | Description |
---|---|---|
data-state | enum | The listbox's open state. |
data-listbox-content | '' | Present on the content element. |
A listbox item, which must be a child of the Listbox.Content
component.
Property | Type | Description |
---|---|---|
value required | string | The value of the item. Default: undefined |
label | string | The label of the item, which is what the list will be filtered by using typeahead behavior. Default: undefined |
disabled | boolean | Whether or not the listbox item is disabled. This will prevent interaction/selection. Default: false |
onHighlight | function | A callback that is fired when the item is highlighted. Default: undefined |
onUnhighlight | function | A callback that is fired when the item is unhighlighted. Default: undefined |
ref $bindable | HTMLDivElement | The underlying DOM element being rendered. You can bind to this to get a reference to the element. Default: undefined |
children | Snippet | The children content to render. Default: undefined |
child | Snippet | Use render delegation to render your own element. See delegation docs for more information. Default: undefined |
Data Attribute | Value | Description |
---|---|---|
data-value | string | The value of the listbox item. |
data-label | string | The label of the listbox item. |
data-disabled | '' | Present when the item is disabled. |
data-highlighted | '' | Present when the item is highlighted, which is either via keyboard navigation of the menu or hover. |
data-selected | '' | Present when the item is selected. |
data-listbox-item | '' | Present on the item element. |
An optional element to track the scroll position of the listbox for rendering the scroll up/down buttons.
Property | Type | Description |
---|---|---|
ref $bindable | HTMLDivElement | The underlying DOM element being rendered. You can bind to this to get a reference to the element. Default: undefined |
children | Snippet | The children content to render. Default: undefined |
child | Snippet | Use render delegation to render your own element. See delegation docs for more information. Default: undefined |
Data Attribute | Value | Description |
---|---|---|
data-listbox-viewport | '' | Present on the viewport element. |
An optional scroll up button element to improve the scroll experience within the listbox. Should be used in conjunction with the Listbox.Viewport
component.
Property | Type | Description |
---|---|---|
ref $bindable | HTMLDivElement | The underlying DOM element being rendered. You can bind to this to get a reference to the element. Default: undefined |
children | Snippet | The children content to render. Default: undefined |
child | Snippet | Use render delegation to render your own element. See delegation docs for more information. Default: undefined |
Data Attribute | Value | Description |
---|---|---|
data-listbox-scroll-up-button | '' | Present on the scroll up button element. |
An optional scroll down button element to improve the scroll experience within the listbox. Should be used in conjunction with the Listbox.Viewport
component.
Property | Type | Description |
---|---|---|
ref $bindable | HTMLDivElement | The underlying DOM element being rendered. You can bind to this to get a reference to the element. Default: undefined |
children | Snippet | The children content to render. Default: undefined |
child | Snippet | Use render delegation to render your own element. See delegation docs for more information. Default: undefined |
Data Attribute | Value | Description |
---|---|---|
data-listbox-scroll-down-button | '' | Present on the scroll down button element. |
A group of related listbox items.
Property | Type | Description |
---|---|---|
ref $bindable | HTMLDivElement | The underlying DOM element being rendered. You can bind to this to get a reference to the element. Default: undefined |
children | Snippet | The children content to render. Default: undefined |
child | Snippet | Use render delegation to render your own element. See delegation docs for more information. Default: undefined |
Data Attribute | Value | Description |
---|---|---|
data-listbox-group | '' | Present on the group element. |
A heading for the parent listbox group. This is used to describe a group of related listbox items.
Property | Type | Description |
---|---|---|
ref $bindable | HTMLDivElement | The underlying DOM element being rendered. You can bind to this to get a reference to the element. Default: undefined |
children | Snippet | The children content to render. Default: undefined |
child | Snippet | Use render delegation to render your own element. See delegation docs for more information. Default: undefined |
Data Attribute | Value | Description |
---|---|---|
data-listbox-group-heading | '' | Present on the group heading element. |
An optional arrow element which points to the content when open.
Property | Type | Description |
---|---|---|
width | number | The width of the arrow in pixels. Default: 8 |
height | number | The height of the arrow in pixels. Default: 8 |
ref $bindable | HTMLDivElement | The underlying DOM element being rendered. You can bind to this to get a reference to the element. Default: undefined |
children | Snippet | The children content to render. Default: undefined |
child | Snippet | Use render delegation to render your own element. See delegation docs for more information. Default: undefined |
Data Attribute | Value | Description |
---|---|---|
data-arrow | '' | Present on the arrow element. |