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Collapsible

A collapsible is a component which expands and collapses a panel.

Properties

Features

  • Can be controlled or uncontrolled.
  • Works for width and height collapsibles.

Installation

To use the collapsible machine in your project, run the following command in your command line:

npm install @zag-js/collapsible @zag-js/react
# or
yarn add @zag-js/collapsible @zag-js/react

This command will install the framework agnostic collapsible logic and the reactive utilities for your framework of choice.

Usage

First, import the collapsible package into your project

import * as collapsible from "@zag-js/collapsible"

The collapsible package exports two key functions:

  • machine — The state machine logic for the collapsible widget.
  • connect — The function that translates the machine's state to JSX attributes and event handlers.

You'll also need to provide a unique id to the useMachine hook. This is used to ensure that every part has a unique identifier.

Next, import the required hooks and functions for your framework and use the collapsible machine in your project 🔥

import * as collapsible from "@zag-js/collapsible"
import { normalizeProps, useMachine } from "@zag-js/react"
import { useId } from "react"

function Collapsible() {
  const [state, send] = useMachine(collapsible.machine({ id: useId() }))

  const api = collapsible.connect(state, send, normalizeProps)

  return (
    <div {...api.rootProps}>
      <button {...api.triggerProps}>Collapse Trigger</button>
      <div {...api.contentProps}>Collape Content</div>
    </div>
  )
}

Listening for changes

When the collapsible state changes, the onOpenChange callback is invoked.

const [state, send] = useMachine(
  collapsible.machine({
    onOpenChange(details) {
      // details => { open: boolean }
      console.log("collapsible open:", details.open)
    },
  }),
)

Disabling the collapsible

Set the disabled machine context property to true to disable the collapsible.

const [state, send] = useMachine(
  collapsible.machine({
    disabled: true,
  }),
)

Animating the collapsible

Use CSS animations to animate the collapsible when it expands and collapses. The --height and --width custom properties are attached to the content part.

@keyframes expand {
  from {
    height: 0;
  }
  to {
    height: var(--height);
  }
}

@keyframes collapse {
  from {
    height: var(--height);
  }
  to {
    height: 0;
  }
}

[data-scope="collapsible"][data-part="content"] {
  overflow: hidden;
  max-width: 400px;
}

[data-scope="collapsible"][data-part="content"][data-state="open"] {
  animation: expand 110ms cubic-bezier(0, 0, 0.38, 0.9);
}

[data-scope="collapsible"][data-part="content"][data-state="closed"] {
  animation: collapse 110ms cubic-bezier(0, 0, 0.38, 0.9);
}

Styling guide

Earlier, we mentioned that each collapsible part has a data-part attribute added to them to select and style them in the DOM.

Open and closed state

When a collapsible is expanded or collapsed, a data-state attribute is set on the root, trigger and content elements. This attribute is removed when it is closed.

[data-part="root"][data-state="open|closed"] {
  /* styles for the collapsible is open or closed state */
}

[data-part="trigger"][data-state="open|closed"] {
  /* styles for the collapsible is open or closed state */
}

[data-part="content"][data-state="open|closed"] {
  /* styles for the collapsible is open or closed state */
}

Focused state

When a collapsible's trigger is focused, a data-focused attribute is set on the root, trigger and content.

[data-part="root"][data-focus] {
  /* styles for the item's focus state */
}

[data-part="trigger"][data-focus] {
  /* styles for the content's focus state */
}

[data-part="content"][data-focus] {
  /* styles for the content's focus state */
}

Methods and Properties

The collapsible's api exposes the following methods and properties:

Machine Context

The collapsible machine exposes the following context properties:

  • idsPartial<{ root: string; content: string; trigger: string; }>The ids of the elements in the collapsible. Useful for composition.
  • onExitComplete() => voidFunction called when the animation ends in the closed state.
  • onOpenChange(details: OpenChangeDetails) => voidFunction called when the popup is opened
  • openbooleanWhether the collapsible is open
  • disabledbooleanWhether the collapsible is disabled
  • open.controlledbooleanWhether the collapsible open state is controlled by the user
  • dir"ltr" | "rtl"The document's text/writing direction.
  • idstringThe unique identifier of the machine.
  • getRootNode() => ShadowRoot | Node | DocumentA root node to correctly resolve document in custom environments. E.x.: Iframes, Electron.

Machine API

The collapsible api exposes the following methods:

  • isOpenbooleanWhether the collapsible is open.
  • isVisiblebooleanWhether the collapsible is visible (open or closing)
  • isDisabledbooleanWhether the collapsible is disabled
  • open() => voidFunction to open the collapsible.
  • close() => voidFunction to close the collapsible.

Accessibility

Adheres to the Disclosure WAI-ARIA design pattern.

Keyboard Interactions

  • Space
    Opens/closes the collapsible.
  • Enter
    Opens/closes the collapsible.

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