Stable in React

Collapsible

A collapsible panel controlled by a button.

Loading React 19.3.1…

Hover a part or use it. The code follows. · Loading React…

177Tests passing in React · 0 failing

9.3 KiBSize

1.30 msOpen

0.60 msClose

0.45 MiBMemory

productdevbook and 18 upstream authors12 commits · last Nov 4

Install#

One package per framework. Collapsible's parts come from it; the anatomy tab at the top shows how they nest.

bun add @▢▢▢▢/react

Three parts. The example uses three of them; the data does not say which are required.

Collapsible.RootGroups all parts of the collapsible.
Collapsible.TriggerA button that opens and closes the collapsible panel.
Collapsible.PanelA panel with the collapsible contents.

Examples#

The demo at the top is the one example this component has so far.

Styling and accessibility#

The parts ship no styles. Style their states with these attributes; the CSS tab at the top has a sheet. The same CSS works in all five frameworks.

[data-open]Present when the collapsible is open. On Root, Panel.
[data-closed]Present when the collapsible is closed. On Root, Panel.
[data-starting-style]Present when the collapsible begins animating in. On Root, Panel.
[data-ending-style]Present when the collapsible is animating out. On Root, Panel.
[data-panel-open]Present when the collapsible panel is open. On Trigger.
[data-disabled]Present when the trigger or the collapsible is disabled. On Trigger.
--collapsible-panel-heightThe collapsible panel's height. On Panel.
--collapsible-panel-widthThe collapsible panel's width. On Panel.

Keyboard

EnterSpaceOpens or closes the panel On Trigger.
EnterSpaceDoes nothing while the collapsible is disabled On Trigger.

Set for you

aria-expanded, aria-controls to the panel while opena screen reader says whether the section is open and where it isTrigger
hidden="until-found" with hiddenUntilFoundfind in page reaches text in the closed panel and opens itPanel

API reference#

7 props across 3 parts, in React syntax, and className, style, render once for every part. Open a row to try it.

Filter props

Collapsible · all parts

Shared propsEvery part that renders an element takes these.

classNameCSS class applied to the element, or a function that returns a class based on the component's state.string | ((state: State) => string | undefined)

styleStyle applied to the element, or a function that returns a style object based on the component's state.React.CSSProperties | ((state: State) => React.CSSProperties | undefined)

renderAllows you to replace the component's HTML element with a different tag, or compose it with another component.React.ReactElement<unknown, string | React.JSXElementConstructor<any>> | ComponentRenderFn<HTMLProps, State>

Use it in React#

What differs from the React API. Switch the framework at the top of the page.

@▢▢▢▢/react is the React 19 package. Its parts, props, data attributes and error messages are upstream Base UI's, and upstream's own tests run against it.

Parts
Each component is its own entry point and exports one namespace named after it.
```
import { Switch } from '@base-ui-next/react/switch'

export function Example() {
  return (
    <Switch.Root>
      <Switch.Thumb />
    </Switch.Root>
  )
}
```
A part renders the element its API reference names, such as a <span> for Switch.Root.
Props and events
Props and callbacks have upstream's names and signatures: onCheckedChange(checked, details), onOpenChange(open, details), onValueChange(value, details). details carries reason, event, cancel() and allowPropagation(). Native handlers are React's (onClick, onKeyDown), and event.preventBaseUIHandler() stops a part's own handler.
Styling
className takes a string or a function (state) => string; style takes an object or a function (state) => object. The state's data-* attributes are on the element for CSS.
render
render takes an element (render={<a href="/docs" />}) or a function (props, state) => element that spreads props on what it returns.
Refs
ref reaches the part's element. Imperative handles are ref props, as upstream: inputRef, and actionsRef ({ validate } on Field and Form, { unmount, close } on Dialog).
Binding
A part is controlled when its value prop (checked, open, value) is set, and uncontrolled with the default form (defaultChecked, defaultOpen, defaultValue). React has no two-way binding: pair the value with its change callback.
From @base-ui/react
Change the import from @base-ui/react/<component> to @▢▢▢▢/react/<component>.
From @base-ui/react
Nothing else changes: props, parts, data attributes and errors are the same.